Oral Communications

The potential of MXenes for catalyzing dissociation reactions

José R. B. Gomesa, José D. Gouveiaa, Á. Morales-Garcíab, Francesc Viñesb, Francesc Illasb

aCICECO-Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal. bDepartment of Materials Science and Physical Chemistry, University of Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain. E-mail: jrgomes@ua.pt

This communication focuses on the potential of two-dimensional pristine carbide or nitride MXenes (Figure 1) for dissociating water1, nitrogen2 and carbon dioxide3. The data arising from a multiscale modeling approach, coupling calculations carried out in the framework of density functional theory, microkinetic modelling and kinetic phase diagrams, suggest that bare MXenes can be highly active catalytic materials for industrial and societal relevant processes as the water gas shift reaction, ammonia production or carbon capture and usage.

Figure 1. MXene bare surface models analyzed in our computational studies.

References

[1] Gouveia, J. D.; Morales-García, Á.; Viñes, F.; Illas, F.; Gomes, J. R. B.; Appl. Catal. B.: Environ., 2020, 260, 118191. [2] Gouveia, J. D.; Morales-García, Á.; Viñes, F.; Gomes, J. R. B.; Illas, F.; ACS Catal., 2020, 10, 5049. [3] Morales-Salvador, R.; Gouveia, J. D.; Morales-García, Á.; Viñes, F.; Gomes, J. R. B.; Illas, F.; ACS Catal., 2021, 11, 11248.

Acknowledgments: The research carried out at the University of Aveiro was developed within the scope of the project CICECO-Aveiro Institute of Materials, Refs. UIDB/50011/2020 and UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology (FCT, MCTES). The research carried out at the University of Barcelona has been supported by the Spanish MINECO/FEDER CTQ2015-64618-R, MICIUN/FEDER RTI2018-095460B-I00 and María de Maeztu MDM-2017-0767 grant and, in part, by Generalitat de Catalunya 2017SGR13 and XRQTC grants. J.D.G. is thankful to project SILVIA, with references PTDC/QUI-QFI/31002/2017 and CENTRO-01-0145-FEDER31002, and also to Project HPC-EUROPA3 (INFRAIA-2016-1-730897), with the support of the EC Research Innovation Action under the H2020 Programme. A.M.-G. thanks the Spanish MICIUN for the Juan de la Cierva postdoctoral grant (IJCI-2017-31979), F. V. is thankful to Ministerio de Economía y Competitividad (MEC) for his Ramón y Cajal (RYC2012-10129) research contract, and F.I. acknowledges additional support from the 2015 ICREA Academia Award for Excellence in University Research. J.R.B.G. and J.D.G. thank FCT for granting access to national computing resources through project Ref. CPCA/A2/6817/2020. All authors are thankful to Red Española de Supercomputación (RES) for the supercomputing time in Marenostrum IV (QS-2019-2-0019), and to COST Action CA18234.

Covalent organic frameworks for the capture of water pollutants

Laura M. Salonen

International Iberian Nanotechnology Laboratory (INL), Av. Mestre José Veiga, Braga 4715-330, Portugal. E-mail: laura.salonen@inl.int

The increasing occurrence of organic contaminants, such as pharmaceutical and pesticides, in water matrices is a major environmental concern. Due to their uniform pore size, high surface area, and tunable pore surface, covalent organic frameworks (COFs) are receiving increasing interest as adsorbents. In this communication, key aspects on the design and synthesis of COFs for contaminant capture will be discussed. The use of COFs for the capture of pharmaceuticals1 and marine biotoxins2 from water will be presented. The adsorption efficiency is further boosted by the preparation of magnetic COF composites.3,4 Additionally, the effect of COF pore surface functionalization on the adsorption of toxins will be discussed.5 Finally, COFs are shown to capture pharmaceuticals efficiently also from natural water samples from the Tagus estuary.6

References

[1] A. Mellah, S. P. S. Fernandes, R. Rodríguez, J. Otero, J. Paz, J. Cruces, D. D. Medina, H. Djamila, B. Espiña, L. M. Salonen, Chem. Eur. J. 2018, 24, 10601-10605. [2] L. M. Salonen, S. R. Pinela, S. P. S. Fernandes, J. Louçano, E. Carbó-Argibay, M. P. Sárria, C. Rodríguez-Abreu, J. Peixoto, B. Espiña, J. Chromatogr. A 2017, 1525, 17-22. [3] V. Romero, S. P. S. Fernandes, L. Rodriguez-Lorenzo, Y. V. Kolen´ko, B. Espiña, L. M. Salonen, Nanoscale 2019, 11, 6072-6079. [4] V. Romero, S. P. S. Fernandes, P. Kovář, M. Pšenička, Y. V. Kolen’ko, L. M. Salonen, B. Espiña, Microporous Mesoporous Mater. 2020, 307, 110523. [5] S. P. S. Fernandes, P. Kovář, M. Pšenička, A. M. S. Silva, L. M. Salonen, B. Espiña, ACS Appl. Mater. Interfaces 2021, 13, 15053-15063. [6] S. P. S. Fernandes, V. F. Fonseca, V. Romero, I. A. Duarte, A. Freitas, J. Barbosa, P. Reis-Santos, L. M. Salonen, B. Espiña, Chemosphere 2021, 278, 130364.

Acknowledgments: This work received funding from BLUEBIO ERA-NET COFUND DIGIRAS (BLUEBIO/0002/2019).

Building a bridge from bulk materials to catalytic membranes for desulfurization processes

Salete S. Balulaa, Rui G. Fariaa, Catarina Diasa, Fátima Mirantea, Ricardo F. Mendesb , Filipe A. A. Pazb, Luís Cunha-Silvaa

aLAQV REQUIMTE, Department of Chemistry, University of Porto, 4169-007 Porto, Portugal. bCICECOAveiro Institute of Materials, Department of Chemistry, University of Aveiro, Campus University of Aveiro, 3810-193 Aveiro, Portugal. E-mail:sbalula@fc.up.pt

The fossil fuels are still the major source of energy applied for many purposes in which we rely upon, as it is transportation, thus much attention has to be and is being given to fossil fuel consumption but also to its production and processing, answering the calls for the evergrowing need of sustainable development.1 One of the most relevant issues related to the combustion of oil fuels is the emission of sulfur-derived products to the atmosphere, such as various sulfur oxides and particulate metal sulfates, which stem from the different sulfurcontaining compounds (SCC) that make up part of the original composition of crude oil. If these SCC are not discarded from the fuel matrix before the combustion, their emission can be the cause of many environmental problems linked to acid rains and associated with several public health issues.2 To mitigate these serious problems, the petrochemical industry must abide by international legislative regulation over the sulfur content present in processed fossil fuels, resorting to desulfurization processes. Alternative technologies have been encouraged to treat more viscose and heavy fuel oils (HFO). Oxidative desulfurization has been viewed as a promising technology to treat HFO.3,4 Most of the success reported studies used bulk catalytic materials. However, these systems are normally associated to catalyst mass loss, frequently occurred during recycling. To mitigate this problem and also to increase bulk catalysts stability, the bulk catalysts can be incorporated in polymeric membranes.5 The application of these catalytic membrane promoted an effective catalyst separation and recycling.

References

[1] N. Abas, A. Kalair and N. Khan, Futures, 2015, 69, 31-49. [2] A. Samokhvalov, Catalysis Reviews, 2012, 54, 281-343. [3] R. Javadli, A. de Klerk, Energy Fuels, 2012, 26, 594-602. [4] S. C. Fernandes, A. M. Viana, B. de Castro, L. Cunha-Silva, S. S. Balula, Sustain. Energy Fuels, 2021, 5, 4032-4040. [5] F. Mirante, R. F. Mendes, R. G. Faria, L. Cunha-Silva, F. A. A. Paz, S. S. Balula, Molecules, 2021, 26, 2404.

Acknowledgments: This research work received financial support from Portuguese national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through the strategic project UIDB/50006/2020 (for LAQV-REQUIMTE). The work was also funded by the European Union (FEDER funds through COMPETE POCI-01-0145-FEDER-031983) and FCT/MCTES by National Funds to the R&D project GlyGold (PTDC/CTM-CTM/31983/2017). LCS and SSB thank FCT/MCTES for funding through the Individual Call to Scientific Employment Stimulus (Ref. CEECIND/00793/2018 and Ref. CEECIND/03877/2018, respectively). RGF thanks FCT and LAQV-REQUIMTE for his PhD grant (Ref. UI/BD/151277/2021).

POMs, MOFs & Carbon materials: the quest for efficient O2 electrocatalysts

Diana M. Fernandes

LAQV@REQUIMTE, Department of Chemistry and Biochemistry, Faculty of sciences, University of Porto, 4169-007 Porto, Portugal. E-mail: diana.fernandes@fc.up.pt

The current global energy crisis, reflected in the depletion of fossil fuels and growth of the environmental pollution has stimulated the development of novel renewable energy storage and conversion technologies. Electrocatalysis plays a central role in clean energy conversion, enabling a number of sustainable processes for future technologies. The oxygen reduction and evolution reactions (ORR and OER) are crucial energy-related processes that take place in fuel cell/electrolyser systems.1 For this reason, regarding the real implementation of these devices, efficient electrocatalysis of these processes is required, stimulating the quest for new, non-expensive, and highly active electrocatalysts during the last years. In this context, polyoxometalates (POMs), metal-organic frameworks (MOFs), and carbon materials (CMs) have attracted a lot of attention due to their remarkable and complementary structural and electrochemical properties.1-3 In this talk a few examples of composite materials based on POMs, MOFs and carbon materials will be presented as electrocatalysts in the oxygen electrochemical reactions.

POMs, MOFs & Carbon Materials

POMs

MOFs CMs

Electrocatalysis

ORR

OER

Scheme 1. Schematic illustration of POMs, MOFs and carbon materials application in ORR and OER reactions.

References

[1] Freire, C.; Fernandes, D.M.; Nunes, M.; Abdelkader, V.K.; ChemCatChem, 2018, 10, 1703-1730. [2] Abdelkader, V.K.; Fernandes, D.M.; Balula, S. S.; Cunha-Silva, L.; Freire, C.; J. Mater. Chem. A, 2020, 8, 13509-13521. [3] Abdelkader, V.K.; Fernandes, D.M.; Balula, S. S.; Cunha-Silva, L.; Freire, C.; ACS Appl. Energy Mater. 2020, 3, 2925−2934.

Acknowledgments: This work received financial support from PT national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through the project UIDB/50006/2020 | UIDP/50006/2020. Acknowledgments are also due to the FCT project FOAM4NER (PTDC/QUI-ELT/28299/2017). DMF also thanks FCT (Fundação para a Ciência e Tecnologia) for funding through program DL 57/2016 – Norma transitória.

Ni-based catalysts supported over activated carbon for CO2 hydrogenation to CH4: The use of cork waste as precursor

Filipe Mateus, Carmen Bacariza, Paula Teixeira, José M. Lopes, Carlos Henriques

CQE-IST, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal. E-mail: carmen.rey@tecnico.ulisboa.pt

CO2 methanation is a key catalytic reaction that can contribute to carbon dioxide emissions abatement and allows storing the temporary surplus of renewable electricity in the natural gas grid (Power-to-Gas). Supported catalysts containing transition (Ni, Co, Fe) and noble (Ru, Rh) metals have been applied in this reaction.1 Among them, the catalytic systems containing Ni are the most promising due to their high catalytic activity, methane selectivity and economic viability. In terms of supports, Al2O3, SiO2, CeO2, ZrO2, hydrotalcites, carbons or zeolites have been reported, being concluded that its nature has a significant impact on catalysts’ properties and performances.1 The use of activated carbon (AC) as support for CO2 methanation catalysts has not been widely studied in the literature yet, but promising results were reported so far.1,2 Indeed, it was suggested that the high surface area of AC allows storing high quantities of both H2 and CO2, turning Ni/AC into an active catalyst for this reaction. Furthermore, the use of waste materials as AC precursors constitutes an interesting strategy which deserves more studies.1 Consequently, in this work cork waste was used as AC precursor for the synthesis of Ni and Ni-Ce catalysts towards CO2 methanation. AC was prepared by physical activation3 and metals were incorporated by incipient wetness impregnation. Samples were characterized by N2 adsorption, CO2 adsorption, XRD and TGA, being finally tested under CO2 methanation conditions (1 bar, 86100 ml h-1 g -1, PCO2 = 0.16 bar). Among all, the synthesized AC presented high textural properties (Figure 1) and the bimetallic catalyst presented the smallest Ni0 crystallites size. The prepared samples exhibited promising results, confirming the interest of cork waste utilization as a support precursor.

References

[1] Bacariza, M.C.; Spataru, D.; Karam, L.; Lopes, J.M.; Henriques, C.; Processes, 2020, 8, 1646. [2] Cam, L.; Ha, N; Khu, L.; Ha, N.; Brown, T.; Aust. J. Chem, 2019, 72, 969-977. [3] Mestre, A.; Pires, R.; Aroso, I.; Fernandes, E.; Pinto, M.; Reis, R.; Andrade, M.; Pires, J.; Silva, S.; Carvalho, A.; Chem. Eng. J., 2014, 253, 408-417.

Acknowledgments: Authors thank FCT (UIDB/00100/2020 and UIDP/00100/2020) for funding.

TiO2/carbon quantum dots composites: a tool for the removal of antibiotics from aquaculture effluents through photodegradation

Valentina Silvaa,b, Carla Patrícia Silvaa, Marta Oterob , Valdemar Estevesa, Diana Limaa

aCESAM & Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal. bCESAM & Department of Environment and Planning, University of Aveiro, 3810-193 Aveiro, Portugal. E-mail: valentinagsilva@ua.pt

The industry of aquaculture has remarkably developed to satisfy the world’s demand for fish and seafood. However, like in all zootechnics, aquacultures use antibiotics, such as oxolinic acid (OXA) and sulfadiazine (SDZ), for disease treatment and prevention2. Since a large part of these antibiotics stays in the aquaculture recirculating water systems, as well as in effluents, ending up in the surrounding water, this constitutes a problem. The presence of antibiotics in the aquatic environment promotes the increase of antimicrobial resistance, so the development of sustainable treatments for antibiotics’ removal is crucial. Among them, photodegradation under natural irradiation may be a promising alternative if a proper efficiency is achieved. Semiconductor photocatalysts, like titanium dioxide (TiO2), and the versatile carbon quantum dots (CQDs) have risen great interest in the scientific community since they are solar driven photocatalysts, cheap to produce and easy to use. This work aimed at verifying the solar driven photocatalytic efficiency of TiO2/CQDs composites in the removal of OXA and SDZ from different water matrices. Two types of CQDs were synthesized under hydrothermal treatment: (i) using citric acid and urea (CQDs-CAU); or (ii) using only citric acid (CQDs-CA). Through a hydrothermal-calcination method, composites were produced by incorporating different percentages ((4%, 5%, 6% or 8%) (w/w)) of CQDs in commercial TiO2 (P25). Solutions of OXA and SDZ (10 mg/L) with pH adjusted to 8.6 were prepared either in 0.001 mol/L phosphate buffer (PB), 30 g/L of synthetic sea salts (SSS) or aquaculture effluent. Then, photodegradation studies were carried out under laboratory-controlled conditions using a solar simulator (Solarbox 1500; Co.fo.me.gra). When compared with the absence of any photocatalyst, 500 mg/L of TiO2/CQDs-CA 4% (w/w) allowed for an OXA half-life time (t1/2) 10.7 times decrease in PB, while 1000 mg/L of TiO2/CQDs-CA 4% (w/w) allowed for 4.7 and 6.6 times decrease of OXA t1/2 in SSS and aquaculture effluent, respectively. In the case of SDZ, 500 mg/L of TiO2/CQDs-CA 4% (w/w) provided a t1/2 decrease of 67.9 times in PB, while 500 mg/L of CQDs-CAUC allowed for 14.5 and 116 times decrease, respectively, in SSS and aquaculture effluent. After irradiation, the antibacterial activity of OXA and SDZ solutions decreased drastically and totally, respectively. The results herein reported indicate that the utilization of the synthesized solar driven photocatalysts may constitute a green solution to remove both OXA and SDZ from aquaculture effluents.

Acknowledgments: This work was funded by FEDER through CENTRO 2020 and by national funds through FCT within the research project REM-AQUA (PTDC/ASP-PES/29021/2017). Diana Lima was funded by national funds (OE), through FCT, in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. Marta Otero and Valentina Silva thank the support by FCT Investigator Program (IF/00314/2015). Also, thanks are due to FCT/MCTES through national funds for the financial support to CESAM (UIDB/50017/2020+UIDP/50017/2020).

Hierarchical zeolites for one step catalytic production of liquid hydrocarbons from syngas

Daniel P. Costaa, Auguste Fernandesa, Eduardo Falabella S.-Aguiarb , José C.B. Lopesc , Bruno F. Machadoc, M. Filipa Ribeiroa

aCentro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, Lisboa 1049-001, Portugal. bDepartment of Organic Processes, School of Chemistry, UFRJ – CT, Bloco E, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ 21941-909, Brazil. cCoLAB Net4CO2 - Network for a Sustainable CO2 Economy, Rua Dr. Júlio de Matos 828-882, 4200-355 Porto, Portugal. E-mail: daniel.pereira.costa@tecnico.ulisboa.pt

Decreasing CO2 emissions is one of the biggest challenges of the current generation in order to achieve a sustainable future. XtL technologies can play an important role in the solution, using the Fischer-Tropsch (FT) reaction to transform syngas (H2 and CO) produced from biomass sources into liquid fuels1. In recent years, bifunctional catalysts comprising acid and metal functionalities have attracted a lot of interest to avoid the final upgrading step and decrease both operational and capital costs. Hierarchical zeolites have been applied successfully in this field but determining how their catalytic performance is affected by differences in the structure and acid properties still needs additional investigation.2 In this work, HZSM-5 hierarchical zeolites with different Si/Al ratios and pore-directing agents (Scheme 1) were prepared and the effect of their acid properties and mesopore size was assessed using the FT reaction (fixed-bed reactor). The bifunctional hybrid catalysts were prepared by physical mixture of zeolite samples with Pt-Al2O3 catalyst and a cobaltbased catalyst for FT synthesis. Before the reaction, 500 mg of catalyst was reduced in situ at 350 ºC with H2 during 10 h. The reaction conditions used in the tests were T = 220 ºC, P = 20 bar, GHSV = 5 L∙gcat –1∙h–1 and H2/CO = 2. XRD characterization results showed a high crystallinity degree for all samples. The N2 adsorption isotherm at –196ºC and thermogravimetric analysis confirmed the successful formation of mesopores with different pore size distributions Differences in acid strength and number of Brønsted sites were detected and quantified using both NH3 and pyridine adsorption. The introduction of the zeolite increased the liquid product yield and changed the product distribution. These changes will be correlated with the acid and structural properties of each zeolite.

Scheme 1. Synthesis diagram of the hierarchical zeolites.

References

[1] Martínez-Vargas, D. X.; Sandoval-Rangel, L.; Campuzano-Calderon, O.; Romero-Flores, M.; Lozano, F.; Ningam, K.D.P.; Mendoza, A.; Montesinos-Castelanos, A.; Ind. Eng. Chem. Res., 2019, 58, 15872-15901. [2] Adeleke, A. A.; Liu, X.; Lu, X.; Moyo, M.; Hildebrandt, D.; Rev. Chem. Eng., 2020, 36, 437-457.

Acknowledgments: DPC thanks CoLAB Net4CO2 for funding and UFRJ for the cobalt based-catalyst and also CQE and FCT for financial funding through project UIDB/00100/2020.

Development of amide functionalized coordination polymers for heterogeneous catalytic applications

Anirban Karmakara, Armando J. L. Pombeiroa,b

aCentro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049–001, Lisbon, Portugal. bРeoples’ Friendship University of Russia (RUDN University), Research Institute of Chemistry, 6 Miklukho-Maklaya Street, Moscow, 117198, Russia. Email:anirbanchem@gmail.com

Coordination polymers (CPs) are crystalline coordination networks consisting of metal ions or clusters and multidentate organic ligands. 1 This area of research is currently undergoing a rapid growth due to their potential applications as functional materials in heterogeneous catalysts, magnetism, nonlinear optics, gas storage and separation, etc. 2 Moreover, CPs constructed from amide based linkers have attracted considerable attention due to their interesting topologies as well as catalytic properties. 3 Thus, we have synthesized various amide functionalized multifunctional carboxylate ligands and employed them for the construction of CPs having different dimensionality. Solvothermal/ hydrothermal reactions of different transition metals with these ligands in presence or absence of an auxiliary ligand give rise to a series of 1D, 2D and 3D CPs. We have characterized them by X‐ray single crystal diffraction, elemental microanalysis, IR spectroscopy, thermogravimetric analysis and powder X-ray diffraction analysis. These CPs act as effective heterogeneous catalysts for various organic transformations, for example Knoevenagel condensation, Henry, transesterification, oxidation and cascade type reactions under mild conditions and can be recycled without losing activity.

Figure 1. Representative example of a 2D coordination polymer obtained by the reaction of an amidoisophthalic acid linker and a Zn(II) salt.

References

[1] Karmakar, A.; Titi, H. M.; Goldberg, I.; Cryst. Growth Des., 2011, 11, 2621–2636. [2] Karmakar, A.; Pombeiro, A. J. L.; Coord Chem Rev., 2019, 395, 86-129. [3] Karmakar, A.; Guedes da Silva, M. F. C.; Pombeiro, A. J. L.; Dalton Trans., 2014, 43, 7795–7810.

Acknowledgments: This work has been supported by the Foundation for Science and Technology (FCT), Portugal (project UIDB/00100/2020 of Centro de Química Estrutural) and by the RUDN University Strategic Academic Leadership Program. AK also thanks the Instituto Superior Técnico and FCT for Scientific Employment contract (Contrato No: ISTID/107/2018) under Decree-Law no. 57/2016, of August 29.

Iron tris(pyrazolyl)methane catalysts in diazo amination reactions

Vasco F. Batista, Diana C. G. A. Pinto, Artur M. S. Silva

LAQV-REQUIMTE & Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal. E-mail: vfb@ua.pt

Carbene insertion reactions, particularly those involving α-diazo esters, are unmatched in their ability to promptly build complex molecules from common accessible reagents.1 While Rhodium, Silver, Iridium and other rare-earth metals are the catalysts of choice in these reactions, Copper(I) and Iron(II) metal ions combined with complex organic ligands are promising alternatives.2 Nevertheless, the high complexity of the ligands and the use of airand water-sensitive Fe(II) and Cu(I) triflate salts discourages their industrial use. Iron(II) tris(pyrazolyl)methanes have been previously synthesized, characterized and applied solely on the oxidation of alcohols.3 However, they remain one of few air-stable Iron(II)-organic complexes. In this work we explored Iron(II) tris(pyrazolyl)methane as a suitable catalyst for diazo insertion reactions. In the presence of NaBArF, FeCH(pz)3Cl2 could perform the difficult amination of α-(diazo)phenylacetate esters with aniline derivatives in 24h and at mild temperatures. This reaction tolerated different substituents in both rings with overall good yields. The analogue FeCH(pz)3Cl3 catalyst was also used to investigate the influence of the metal’s oxidation state in the reaction. A DFT analysis allowed us to propose a viable mechanism for this reaction, through the formation of an intermediate metal carbene species. This stands perhaps as the first example of an air-stable Iron(II) catalyst in diazo insertion reactions. As so, it stands as inspiration for the development of asymmetric variants - using chiral tris(pyrazolyl)methanes - and of “in water” or heterogeneous reactions - through the already reported functionalization of the ligand’s methine group.4

Scheme 1. Iron(II) tris(pyrazolyl)methane-catalysed diazo amination reaction.

References

[1] A. Ford, H. Miel, A. Ring, C.N. Slattery, A. Maguire, M. McKervey, Chem. Rev., 2015, 115, 9981. [2] V. Batista, D. Pinto, A. Silva, ACS Catal., 2020, 10, 10096. [3] A. Ribeiro, I. Matias, E. Alegria, A. Ferraria, A. Rego, A. Pombeiro, L. Martins, Catalysts, 2018, 8, 69. [4] A. Mahmoud, L. Martins, M. Silva, A. Pombeiro, Catalysts, 2019, 9, 611.

Acknowledgments: This work received financial support from PT national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through the project UIDB/50006/2020. Thanks are due to the Portuguese NMR Network. Vasco F. Batista also thanks FCT for his PhD grant (PD/BD/135099/2017).

Climateric fruits ripening mitigation - Ag-based zeolites as efficient sorbents for the removal of ethylene

Ricardo F. Ferreiraa , Auguste Fernandesa, João P. Lourençoa,b, João M. Silvaa,c, Filipa Ribeiroa

aCentro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049001, Lisboa, Portugal, bFaculdade de Ciências e Tecnologia, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal, cADEQ, Instituto Superior de Engenharia de Lisboa, IPL, R. Conselheiro Emídio Navarro, 1959-007, Lisboa, Portugal. E-mail: ricardoferreira@tecnico.ulisboa.pt

Most fresh products that are found in UE come from Mediterranean zone. However, most of them are perishables, leading to waste and losses in profit. In fact, climacteric fruits (apples, pears, tomatoes, avocados, ...) suffer from continuous postharvest ripening, a result of respiration gases, since Volatile organic compounds (VOCs) like ethylene, a natural ripening hormone,1 are easily produced. Removing ethylene by adsorption has the advantage to be very cheap, when compared with oxidative KMnO4 method.2 Zeolites present as a natural solution due to their characteristics to be good sorbents. They can be used as acid catalysts and are suitable for stabilizing small metal clusters (e.g. Ag).3 This work consists of comparing ethylene capacity of silver-based zeolites with two different structures (MFI and BEA) and Si/Al ratios. Ethylene breakthrough curves experiments, with the following mixture: C2H4 (50 ppm), He (10 % vol.) and N2, were performed. The results are presented in Figure 1, for BEA (Si/Al= 12.5 and 32.5) and MFI (Si/Al= 15 and 25). In each case, protonic zeolites are compared with Ag-loaded zeolites. Independently of the structure, one can see that the presence of Ag greatly enhances the adsorption ethylene capacity. Protonic forms do not adsorb, or just adsorb small amounts of ethylene. When Ag is present, the maximum ethylene capacity greatly increases. C2H4 adsorption capacity also increases when the zeolite Si/Al ratio decreases. UV-Vis DRS studies combined with TPR experiments were used to define in detail the nature of the different Ag species present. Results show that cationic Ag species (Ag+, Agnd+ ) are probably responsible for the excellent performance of those Ag-based zeolite sorbents.

Figure 1. Ethylene adsorption breakthrough curves for zeolites a) ZSM-5 and b) BEA.

References

[1] Tripathi K., Pandey S., Malik M., Kaul T., J. Environ. Appl. Bioresearch, 2016, 4, 27–34. [2] Pathak N., Mahajan P., Ref. Modul. Food Sci., 2017, Elsevier. [3] Cisneros L., Gao F., Corma A., Microporous Mesoporous Mater., 2019, 283, 25–30.

Acknowledgments: Nano4fresh/ PRIMA/0015/2019 and also CQE and FCT for financial funding through project UIDB/00100/2020.

Hybrid magnetic carbon nanocomposites for environmental catalytic applications

Rui S. Ribeiroa,b, Adrián M.T. Silvaa,b, Joaquim L. Fariaa,b, Helder T. Gomesc

aLaboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. bALiCE – Associate Laboratory in Chemical Engineering, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. cCentro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia , 5300-253 Bragança, Portugal. E-mail: rsribeiro@fe.up.pt

Meeting current quality requirements for wastewater reuse is a great challenge, in which materials science and catalysis hold great potential. Bearing this in mind, our work has been focused on developing highly active and stable hybrid magnetic carbon nanocomposites for environmental catalytic applications, such as catalytic wet peroxide oxidation (CWPO) and activated persulfate oxidation. A detailed catalyst design (Figure 1), based on the understanding of the surface reactions and interactions involved in the CWPO process,1,2 has allowed us to develop a high performance ferromagnetic graphitic nanocomposite (CoFe2O4/MGNC).3 CoFe2O4/MGNC was then employed in CWPO, activated persulfate oxidation4 and used to develop a new application –coined as magnetically activated catalytic wet peroxide oxidation (MA-CWPO). 5 This communication reports the main findings obtained throughout these steps.

Figure 1. Steps taken to develop a high-performance catalyst for environmental applications.

References

[1] Ribeiro, R.S.; Silva, A.M.T.; Figueiredo, J.L.; Faria, J.L.; Gomes, H.T.; Catal. Today, 2017, 296, 66-75. [2] Ribeiro, R.S.; Silva, A.M.T.; Tavares, P.B.; Figueiredo, J.L.; Faria, J.L.; Gomes, H.T.; Catal. Today, 2017, 280, 184-191. [3] Ribeiro, R.S.; Rodrigues, R.O.; Silva, A.M.T.; Tavares, P.B.; Carvalho, A.M.C.; Figueiredo, J.L.; Faria, J.L.; Gomes, H.T.; Appl. Catal. B, 2017, 219, 645-657. [4] Ribeiro, R.S.; Frontistis, Z.; Mantzavinos, D.; Silva, A.M.T.; Faria, J.L.; Gomes, H.T.; J. Chem. Technol. Biotechnol., 2019, 94, 24252432. [5] Ribeiro, R.S.; Gallo, J.; Bañobre-López, M.; Silva, A.M.T.; Faria, J.L.; Gomes, H.T.; Chem. Eng. J., 2019, 376, 120012. Acknowledgments: This work was financially supported by project NORTE-01-0145-FEDER-031049 (InSpeCt) funded by FEDER funds through NORTE 2020 - Programa Operacional Regional do NORTE, and by national funds (PIDDAC) through FCT/MCTES. We would also like to thank the scientific collaboration under Base-UIDB/50020/2020 and Programmatic-UIDP/50020/2020 Funding of LSRE-LCM - funded by national funds through FCT/MCTES (PIDDAC), and Base Funding UIDB/00690/2020 of the Centro de Investigação de Montanha (CIMO) - funded by national funds through FCT/MCTES (PIDDAC). R.S. Ribeiro also thanks SPQ – Sociedade Portuguesa de Química, for the Ramôa Ribeiro Best PhD Thesis Award, and the invitation to deliver this oral communication.

Characterization of the surface chemistry of carbon materials by TPD: An assessment

Raquel P. Rocha, Manuel Fernando R. Pereira, José L. Figueiredo

Laboratory of Separation and Reaction Engineering—Laboratory of Catalysis and Materials (LSRE-LCM), Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. E-mail: rprocha@fe.up.pt

The increasing role assumed by carbon materials in technological applications is intrinsically linked to a better understanding of the carbon surface chemistry as a result of reliable methods of analysis. X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD) techniques allow to obtain qualitative and quantitative information on individual functional groups on the carbon surface. In this context, TPD has established itself as an alternative technique to Boehm titration or XPS,1 being especially adequate for the characterization of oxygen functional groups on carbon materials with extended porosity.2 This work aims to recover the basic principles required to perform an adequate TPD-MS analysis, allowing for the correct assessment (qualitatively and quantitatively) of the oxygenated groups on the surface of carbon materials. The relevance of the information obtained through the technique in order to correlate the properties of carbon materials with their performance in practical applications will also be highlighted, using examples from the literature.

Figure 1. Oxygen, nitrogen and sulfur surface groups incorporated on carbon materials and techniques for their identification/quantification (reprinted from 3).

References

[1] Figueiredo, J.L.; Pereira, M.F.R.; Freitas, M.M.A.; Órfão, J.J.M. Carbon, 1999, 37, 1379-1389. [2] Figueiredo, J.L.; Pereira, M.F.R. Catal. Today, 2010, 150, 2-7. [3] Rocha, R.P.; Soares, O.S.G.P.; Figueiredo, J.L.; Pereira, M.F.R. C-J. Carbon Res., 2016, 2, 17.

Acknowledgments: This work was financially supported by Base (UIDB/50020/2020) and Programmatic (UIDP/50020/2020) Funding of the Associate Laboratory LSRE-LCM—funded by national funds through FCT/MCTES (PIDDAC), by NORTE-01-0145-FEDER-000054 funded by CCDR-N (Norte2020) and by the project BiCat4Energy (PTDC/EQU‐EQU/1707/2020).

Atomic-level description of 31P-bearing NMR probe molecules adsorbed on zeolites

Carlos Bornesa, Michael Fischerb, Jeffrey A. Amelsea, Carlos F. G. C. Geraldesc, João Rochaa, Luís Mafraa

aCICECO, Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal. bFaculty of Geosciences, University of Bremen; MAPEX Center for Materials and Processes, University of Bremen, 28359 Bremen, Germany. cDepartment of Life Sciences and Coimbra Chemistry Center, Faculty of Science and Technology, University of Coimbra; CIBIT-Coimbra Institute for Biomedical Imaging and Translational Research, 3000-548 Coimbra, Portugal. E-mail: cbornes@ua.pt

Providing an accurate description of the nature, strength, and siting of acid sites in zeolites is fundamental to fathom their reactivity and catalytic behavior, and despite decades of research, this endeavor remains a major challenge. Trimethylphosphine oxide (TMPO) has been proposed as a reliable probe molecule to study the acid properties of solid acid catalysts, allowing the identification of Brønsted acid sites with distinct acid strengths. Recently, doubts have been raised regarding the assignment of the 31P NMR resonances of TMPOloaded zeolites.1 Herein we show that a judicious control of TMPO loading combined with 2D 1H31P HETCOR solid-state NMR, DFT, and ab initio molecular dynamics modeling provides an unprecedented atomistic description of the host−guest and guest−guest interactions of TMPO molecules confined onto HZSM-5 pores. 31P NMR resonances usually assigned to TMPO molecules interacting with Brønsted sites with distinct acid strength, arise instead from changes in the probe molecule confinement promoted by different acid site siting. This work overhauls the current interpretation of NMR spectra, raising important concerns about the widely accepted use of probe molecules for studying acid sites in zeolites.2

Scheme 1. Structure and calculated 31P chemical shifts of TMPO interaction with distinct Brønsted acid sites.

References

[1] Bornes, C.; Sardo, M.; Lin, Z.; Amelse, J.; Fernandes, A.; Ribeiro, M. F.; Geraldes, C.; Rocha, J.; Mafra, L. Chem. Commun., 2019, 55, 12635–12638. [2] Bornes, C.; Fischer, M.; Amelse, J. A.; Geraldes, C. F. G. C.; Rocha, J.; Mafra, L. J. Am. Chem. Soc., 2021, 143, 13616–13623.

Acknowledgments: C.B. acknowledges FCT for Doctoral Fellowship PD/BD/142849/2018 integrated in the Ph.D. program in NMR applied to chemistry, materials, and biosciences (Grant PD/00065/ 2013). This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, Grants UIDB/ 50011/2020 and UIDP/50011/2020, financed by national funds through the FCT/MEC and when appropriate cofinanced by FEDER under the PT2020 Partnership Agreement. We also thank FCT for funding the project PTDC/QEQ-QAN/6373/2014. This work was supported by the North-German Supercomputing Alliance (HLRN).

Immobilized carbon-based semiconductor materials for organic synthesis using an innovative photoreactor: the NETmix

Dânia S. M. Constantino, Madalena M. Dias, Adrián M. T. Silva, Cláudia S. G. Silva, Joaquim L. Faria

Laboratory of Separation and Reaction Engineering – Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Email: daniasmc@fe.up.pt

Some recent studies have shown that light-emitting diodes (LEDs), which are high-effective light sources, leading to CO2 footprint reduction. 1 Integrating micro-structured reactors with visible light sources can be a good strategy to improve photocatalytic processes’ efficiency. Besides a larger surface area to reaction volume ratio, an higher spatial illumination homogeneity can be reached with better light penetration through the entire reactor when compared with conventional large-scale reactors. 2 Process intensification strategies have considered immobilized catalytic systems as a fundamental key for safer and cleaner processes by reducing capital and operating costs avoiding downstream units for catalyst recovery. In this work, a novel photocatalytic film (Figure 1) was prepared and placed into a micro-meso structured reactor irradiated by visible light-emitting diodes aiming to reach a high-performance photocatalytic system. The material was duly characterized and its catalytic performance was evaluated to synthesize some aromatic aldehydes from the selective photocatalytic oxidation of different alcohols. All experimental runs were carried out under environmental-friendly conditions and very promising results were obtained regarding conversion and selectivity.

Figure 1. Carbon nitride-based polymeric film immobilized (left) in NETmix photoreactor (right).

References

[1] Dieleman, J., P. De Visser, and P. Vermeulen. Reducing the carbon footprint of greenhouse grown crops: Re-designing LED-based production systems. in VIII International Symposium on Light in Horticulture 1134, 2016. [2] Matsushita, Y., et al., Pure Appl. Chem., 2007, 79, 1959-1968.

Acknowledgments: This work was financed by UIDB/50020/2020 and UIDP/50020/2020 funding of LSRE-LCM through FCT/MCTES(PIDDAC) and by project POCI-01-0145-FEDER-031398 funded by ERDF and by FCT.

Electrodeposited metal foams: on the quest of improved catalysts for CO2 electroreduction

P. Arévalo-Cid, M.F. Montemor, A.P.C. Ribeiro, L.M.D.R.S. Martins

Centro de Química Estrutural, Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Av Rovisco Pais, 1049-001 Lisboa, Portugal. E-mail: pabloarevalo@tecnico.ulisboa.pt

Climatic change due to the excess of greenhouse gases (GHGs) in the atmosphere is a major concern for society. Since the reduction of the release of CO2, the main GHG in terms of quantity, is still insufficient, novel strategies have been proposed to minimize their effects. Carbon dioxide electrochemical reduction reaction (CO2ERR) is a route to convert unwanted CO2 into chemical products of interest (ethanol, methane…). The main challenge for implementing CO2ERR is by finding novel electrocatalysts with improved efficiency and selectivity. As the CO2ERR is a process taken at the surface of the electrocatalyst, elevated surface areas are required. In this sense, metal foams are potential candidates due to their 3D porous microstructure. The hydrogen bubbling dynamic template-electrodeposition (HBDT-ED) is a simple, inexpensive, scalable, flexible, and environmentally friendly synthesis method that allows variations on composition, morphology, structure, and porosity of the foams just by adjusting the synthesis conditions.1 Cu is a well-known base material for the preparation of CO2ERR catalysts due to its ability to favor C-C bonds formation.2 The HBDT-ED allows tuning copper foams structure to incorporate doping metals, that have been reported as efficiency enhancers.3 In this research, porous Cu metal foams doped with several metals are proposed as electrocatalysts for CO2ERR. Different experimental parameters (CO2 concentration, applied potential, electrode composition, microstructure,…) will be evaluated with the aim to optimize the system for CO2 conversion.

References

[1] Arévalo-Cid, P.; Adán-Más, A.; T.M.Silva, T.M.; Rodrigues, J.A.; Maçôas, E.; Vaz, M.F.; Montemor. M.F.; Mater. Charact., 2020, 169, 110598. [2] Zhu, Q.; Sun, X.; Yang, D.; Ma, J.; Kang, X.; Zheng, L.; Zhang, J.; Wu, Z.; Han, B.; Nat. Commun., 2019, 10, 3851. [3] Vasileff, A.; Xu, C.; Jiao, Y.; Zheng, Y.; Qiao, S-Z.; Chem, 2018, 4, 1809-1831.

Acknowledgments: The authors acknowledge the funding from Fundação para a Ciência e a Tecnologia. This work was funded by national funding from FCT – Fundação para a Ciência in the frame of the project PTDC/QUI-ELT/28299/2017, PO Lisboa 2020 and Portugal 2020, and UIDB/00100/2020 and 2021. P. Arévalo-Cid also would like to thank FCT for the founding through the contract CEECIND/01965/2018. A. P. C. Ribeiro thanks Instituto Superior Técnico for the Scientific Employment contract IST-ID/119/2018.

Biochar based catalysts for sustainable biomass valorisation

Andreia F. Peixoto, Ruben Ramos, Bruno Jarrais, Inês S. Marques, Renata Matos, Diana M. Fernandes, Cristina Freire

LAQV-REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade de Porto, 4169-007 Porto, Portugal. E-mail: andreia.peixoto@fc.up.pt

Biomass thermochemical processing is widely employed to produce syngas, bio-oils and platforms chemicals. A typical residue byproduct of these processes is biochar; an inexpensive, environmentally friendly and easily-produced carbonaceous material that can be further used for the preparation of novel catalysts.1 In this work, solid biochar materials has been produced from vineyard pruning wastes. The physicochemical properties were improved by an activation treatment. Then, the activated biochar was functionalized by: (i) the addition of -SO3H groups using different sulfonation agents to obtain BioC-SO3H;2 and (ii) incorporation of metal-nitrogen-doped phases (M-N/BioC) (M= Co, Cu, Ni, etc.). All the catalysts have been used in the conversion of Furfural (FUR) and 5hydroxymethylfurfural (HMF) to valued added derivatives, Scheme 1. Full HMF conversion together with outstanding ethyl levulinate (EL) yields (up to 84%) were achieved at 130 °C and after 6 h, Scheme 1a). 2 The catalytic activity of the M-N-Bioc has been tested for Catalytic transfer hydrogenation (CTH)3 of furfural (FUR), using formic acid as hydrogen donor at 150-170 °C and up to 10 h reaction time. High yields (up to 80%) towards FUR alcohol (industrially valuable biomass-derived intermediate for the preparation of new biopolymers) were observed, Scheme 1b), establishing a promising catalytic route to valorise a biomass platform molecule using 3d-transition metal-based catalysts in absence of molecular hydrogen. The efficiency of M-N-Bioc has been also evaluated in electrocatalytic O2 reactions.

a) b)

Scheme 1. a) Production of ethyl levulinate from HMF over BioC-SO3H; b) CTH of furfural over M-N-Bioc.

References

[1] Lee, J.; Kim, K.-H.; Kwon E. E.; Renew. Sust. Energ. Rev., 2017, 77, 70. [2] Peixoto, A.F.; Ramos, R.; Moreira, M.M.; Soares, O.S.G.P.; Ribeiro, L.S.; Pereira, M.F.R.; Delerue-Matos, C.; Freire C.; Fuel, 2021, 303, 121227. [3] Ramos, R.; Peixoto, A.F.; Arias‐Serrano, B.I.; Soares, O.S.G.P.; Pereira, M.F.R.; Kubička, D.; Freire, C.; ChemCatChem, 2020, 12, 1467.

Acknowledgments: This work was financial supported from PT national funds (FCT/MCTES) through the project UIDB/50006/2020 and by the FEDER—COMPETE and by National Funds through FCT within the scope of the project “PTDC/BII-BIO/30884/2017—POCI-01-0145-FEDER-030884”. AFP and DMF thank FCT for funding through program DL 57/2016 – Norma transitória.

Sustainable catalytic processes for the development of photosensitive polymeric materials

Andreia C. S. Gonzalez, Inês G. Cruz, Rafael T. Aroso, Iúri Tavares, Fábio M. S. Rodrigues, Rui M. B. Carrilho, Mariette M. Pereira

CQC, Departamento de Química Universidade de Coimbra, Rua Larga, 3004-535 Coimbra (Portugal) Email: andreacsgonzalez@gmail.com

Photosensitive polymers are prominent materials, widely used in electronic and medicinal applications.1,2 Among them, polyvinyl chloride (PVC)-based polymers are widely used in medicine, due their lightweight, durability, low cost and easy processability, which turn them useful candidates for manufacture of medical devices, such as endotracheal tubes and catheters. However, PVC presents several environmental issues, particularly regarding its obtention from non-renewable sources and its long-life, with consequent difficult biodegradability. On the other hand, polycarbonates are sustainable alternatives to PVCbased polymers, also with great potential in the medicine field, due to their optical clarity, heat resistance, high impact strength, dimensional stability, low water absorption, ease of sterilization, biocompatibility, as well as easier and less pollutant biodegradability.3 Advantageously, they can be easily obtained through catalytic copolymerization reactions between epoxides and carbon dioxide (CO2), which is a green, non-pollutant and high atom economy synthetic approach.4 In this communication, we present our recent achievements regarding the development of photosensitive polymeric materials, through two different approaches (Figure 1). The first approach consists of the adsorption of photosensitizer molecule in PVC, while the second consists of the one-pot synthesis of photosensitive green polycarbonate materials, 4 through catalytic CO2 addition reactions to epoxides. Antimicrobial in vitro photodynamic inactivation studies will be presented for the different photosensitive materials in order to assess and select the most promising for development of future photosensitive materials.

Figure 1. Approaches for preparation of photosensitive polymeric materials.

References

[1] Oyama T., Polym. J., 2018, 50, 419. [2] Zangirolami A. C., Dias L. D., Blanco K. C., Vinagreiro C. S., Inada N. M., Arnaut L. G., Pereira M. M., Bagnato V. S., Proc. Natl. Acad. Sci. U.S.A., 2020, 117, 22967. [3] Nimmagadda A.; Liu X.; Teng P.; Su M.; Li Y.; Qiao Q.; Khadka N. K.; Sun X.; Pan J.; Xu H.; Li Q.; Cai J. Biomacromolecules, 2017, 18, 87. [4] Carrilho R. M. B., Dias L. D., Rivas R., Pereira M. M., Claver C., Masdeu-Bultó A. M., Catalysts, 2017, 7, 210.

Acknowledgments: The authors acknowledge funding by FCT (Fundação para a Ciência e Tecnologia), QREN/FEDER (COMPETE Programa Operacional Factores de Competitividade) for projects UIDB/00313/2020 and PTDC/QUIOUT/27996/2017 (DUALPI). Andreia C. S. Gonzalez thanks FCT for PhD grant UI/BD/150804/2020. Rafael T. Aroso thanks FCT for PhD grant PD/BD/143123/2019. This work has been developed in the framework of “FOTOVID” project by LASERLEAP. Project supported by CENTRO 2020 of PT2020 through the European Regional Development Fund (ERDF).

Silica and metal nanoparticles for heterogeneous catalysis in alternative media

L. C. Branco, K. Zalewska, L. Filipe, C. Melo, A. Nunes, S. Gago

LAQV/REQUIMTE, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal. E-mail: l.branco@fct.unl.pt

Nowadays, the development of sustainable and recyclable catalytic reaction media for the preparation of different valuable organic products is highly required.1 The discovery of chiral organic molecules (e.g. L-proline) as innovative organocatalysts is one of the interests in modern catalysis and biological chemical applications.1 For other side, chemical reduction of CO₂ can produce various value-added products such as carbon monoxide, formic acid, methane, methanol, higher chain alkanes and others with potential to be used as fuels or as building blocks for fuel production.2 In last years, our group have been worked in the development of task-specific Ionic Liquids and catalytic systems for application in different organic transformation.3 Herein, we will present 1) Some examples of sustainable approaches for asymmetric organocatalysis including the use of mesoporous silica nanoparticles (MSNPs) based BioCILs as innovative catalysts will be reported. Some MSNPs based BioCILs have showed remarkable performance as chiral organocatalysis in asymmetric direct aldol and Michael addition reactions. For many cases, pure chiral products in good to excellent yields and significant enantiomeric excesses comparable or higher than conventional systems can be achieved. 2) Our recent achievements including the efficient carbon dioxide hydrogenation to

methane using Ruthenium nanoparticles (Ru-NPs) prepared in situ in ionic

liquid media. 4 Different fluorinate anions based ILs as reaction media exhibited a greater catalytic activity on the methane production. Also, the catalytic conversion of epoxides to cyclic carbonate in the presence of biphasic CO2/IL and Zn catalysts have been studied.5

References

[1] Xiang, S.-H., Tan, B. Nature Comm., 2020, 11, 3786. [2] Melo, C. I.; Szczepańska, A.; Bogel-Łukasik, E.; da Ponte, M. N.; Branco, L. C. ChemSusChem, 2016, 9, 1081. [3] Branco, L.C., Serbanovic, A., Ponte, M.N., Afonso, C.A.M., ACS Catal. 2011, 1, 1408. [4] Melo, C. I.; Rente, D.; Nunes Da Ponte, M.; Bogel-Łukasik, E.; Branco, L. C. ACS Sustainable Chem. Eng., 2019, 7, 11963. [5] Paninho, A. B., Forte, A., Zakrzewska, M. E., Mahmudov, K. T., Pombeiro, A. J. L., Guedes da Silva, M. F. C, da Ponte, M. N. Branco, L. C., Nunes, A. V. N. Mol. Catal., 2021, 499, 111292.

Acknowledgments: The authors thanks to Fundação para Ciência e Tecnologia for financial support in the projects PTDC/QUI-QOR/32406/2017, PEst-C/LA0006/2013, RECI/BBBBQB/0230/2012 as well as “SunStorage- Harvesting and storage of solar energy”, with reference POCI- 01-0145-FEDER-016387 and FCT-CAPES (2019-2020) The NMR spectrometers are part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project N◦ 022161 (co-financed by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC).This work was supported by the Associate Laboratory for Green Chemistry – LAQV which is financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020).

Carbon dots-composite materials: Synthesis, characterization, and photocatalytic activity

Gonçalo S. Catalãoa,b, Olinda C. Monteirob, José V. Prataa,c

aDepartamento de Engenharia Química, ISEL – Instituto Politécnico de Lisboa, Portugal. bCQE-FCUL,

Faculdade de Ciências, Universidade de Lisboa, Portugal.

cCentro de Química-Vila Real, Universidade de Trás-os-Montes e Alto Douro, Vila Real, Portugal. E-mail: a37085@alunos.isel.pt

The photocatalytic degradation of organic persistent water pollutants is a methodology extensively investigated in modern times to remediate the issues caused by these contaminants. In this work the preparation and characterization of several environmentally friendly composite photocatalysts based on harmless solid supports (e.g., silica and alumina) and carbon dots (Cdots) is described. These catalysts were used in the photodegradation of caffeine, a well-known model pollutant.1 The photocatalysts were prepared either by a one-pot hydrothermal synthesis using olive mill wastewaters as carbon precursors2 in conjunction with distinct amounts of the solid matrices (samples Cdots-1:SiO2 and Cdots-2:SiO2) or by mixing of the already synthesized Cdots with the same matrices, pristine and hydrothermally treated (samples Cdots/SiO2 and Cdots/SiO2-HT). The photocatalysts were structurally and morphologically characterized by FTIR, UV-Vis diffuse reflectance/absorption and photoluminescence spectroscopies, XRD, and SEM/TEM. The photodegradation of caffeine was carried out under UV-Vis radiation using a mercury lamp, and followed by UV-Vis spectroscopy (Figure 1). The Cdots-1:SiO2 composite, produced by the one-pot methodology using higher Cdots:SiO2 ratio, showed the best photocatalytic activity, reaching the total caffeine photodegradation within 1 h of irradiation (Figure 1). When no catalyst was used (photolysis), degradation of caffeine was not complete even after 2 h of irradiation. These results clearly demonstrate a significant improvement over the degradation of caffeine.

1,0

0,8

caffeine

0 C/C

0,6

0,4

0,2

0,0 PhotolysisPhotolysis SiO2 SiO2 SiO2-HTSiO2-HT Cdots/SiO2 Cdots/SiO2 Cdots/SiO2-HT Cdots/SiO2Cdots-1:SiO2 HT Cdots-2:SiO2 Cdots-1:SiO2

Cdots-2:SiO2

-15 0 15 30 45 60 75 90 105 120 time (min) Figure 2. Degradation profiles of a 20 ppm caffeine solution under UV-Vis radiation as a function of time, using the prepared samples as photocatalysts.

References

[1] Barrocas, B.T.; Conceição Oliveira, M.; Nogueira, H.I.S.; Fateixa, S.; Monteiro, O.C. ACS Appl. Nano Mater., 2019, 2, 1341-1349. [2] Sousa, D.A.; Costa, A.I.; Alexandre, M.R.; Prata, J.V. Sci. Total Environ, 2019, 647, 1097-1105.

Acknowledgments: Thanks are due to the Fundação para a Ciência e Tecnologia for financial support under the projects UIDB/00100/2021, UIDB/00616/2021 and UIDP/00616/2021.

Tuning the catalytic reduction of nitro-arenes using artificial intelligence

Filipe Teixeira, Edgar Silva-Santos, M. Natália D. S. Cordeiro

LAQV-REQUIMTE/Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal. E-mail: filipe.teixeira@fc.up.pt

The development and deployment of novel catalytic solutions is a complex task, dynamic, multi-scale endeavour. In particular, the development of new heterogeneous catalysts has been done mainly under a trial-and-error paradigm. Recently, however, the development of Machine Learning (ML) applications in the realm of chemistry uncovered a new paradigm, were data-driven ML models can guide chemists to attain the best possible performance from their existing catalysts, as well as further the chemical insights to guide future experiments.1 In this work, we report the performance of several ML models of varying complexity aiming at predicting the catalytic performance of certain materials towards the catalytic reduction of nitro-arenes. These models were trained using data from the scientific literature covering a diverse range of catalytic materials. Our results show that careful implementation of data pretreatment strategies leads to a dramatic increase in the accuracy of the resulting ML models, resulting in significant savings in computational cost. What is more, these faster and more accurate models were explored using Artificial Intelligence optimization algorithms for finding new optimal conditions of deploying a particular catalyst. Finally, we also present the current state of the art of using the ML models to find the most desirable catalyst characteristics for the reduction of a given substrate under predetermined conditions.

Scheme 1. General workflow.

References

[1] Toyao, T.; Maeno, Z.; Takakusagi, S.; Kamachi, T.; Takigawa, I.; Shimizu, K.; ACS Catal., 2020, 10, 22602297.

Acknowledgments: This work received financial support from FCT - Fundação para a Ciência e Tecnologia through funding for the project PTDC/QUI-QIN/30649/2017. The authors would like to thank also the FCT support to LAQVREQUIMTE (UID/QUI/50006/2020).