A bifunctional photoaminocatalyst for the alkylation of aldehydes: Design, analysis, and mechanistic studies

This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Catalysis, copyright ©2018 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/abs/10.1021/acscatal.8b01331A bifunctional photoaminocatalyst based on imidazolidinone and thioxanthone is presented. The preparation of these catalysts proceeds in a two-step synthesis that allows an easy tuning of the steric properties. The photophysical and electrochemical data of the imidazolidinone photocatalysts have been determined, indicating that the catalysts can work under visible light conditions. To corroborate the experimental observations, ground state geometry optimization and energy transition studies of thioxanthone and bifunctional catalyst 4c were optimized by time-dependent density functional theory (TD DFT) calculations. The alkylation of aldehydes with this photoaminocatalyst works with high enantioselectivities and yields due to the stereoelectronic properties of the catalyst. A rational mechanistic cycle based on different mechanistic experiments, TD DFT calculations, and laser flash photolysis is presentedThe Spanish Government (CTQ2015-64561-R) and the European Research Council (ERC-CG, Contract 647550) are acknowledge

Holy Water: Photo-Brightening in Quasi-2D Perovskite Films under Ambient Enables Highly Performing Light-Emitting Diodes

Quasi-2D perovskites provide new opportunities for lighting and display applications due to their high radiative recombination and excellent stability. However, seldom attention has been placed on their self-stability/working operation under ambient storage. Herein, quasi-2D perovskites/Polyethylene oxide (PEO) films are studied, showing an unforeseen photo-brightening effect under ambient storage (i.e., an increase of the photoluminescence quantum yield from 55% to 74% after 100 days). In stark contrast, those stored under a dark/inert atmosphere show a significant decrease down to 38%. This counterintuitive phenomenon responds to the increasing radiative recombination rate caused by the passivation of the surface Br vacancies in the presence of physically adsorbed water molecules, as corroborated by in situ/ex situ X-ray photoelectron spectroscopy and density functional theory calculations. Capitalizing on this surprising effect, stable light-emitting diodes (LEDs) using quasi-2D perovskites/PEO color filters are fabricated, realizing high stabilities of ≈400 h@10 mA under operating ambient conditions, representing a 20-fold enhancement compared to LEDs with 3D counter partners. Hence, this study reveals a unique insight into the impact of water passivation on the optical/structural properties of quasi-2D perovskite films, broadening their applications under operating ambient conditions.Y.D. thanks the financial support from the China Scholarship Council (CSC, no. 201808440326). Financial support has been received from AEI-MINECO/FEDER, UE through the Nympha Project (PID2019-106315RB-I00), the regional government of "Comunidad de Madrid" and the European Structural Funds through FotoArt-CM Project (S2018/NMT-4367). F.O. acknowledges funding from the Marie Skłodowska-Curie grant agreement no 754382. M.U.K. and G.N. thank ELI-ALPS, which is supported by the European Union and co-financed by the European Regional Development Fund (GI-NOP-2.3.6-15-2015-00001). This publication has also received funding from PANOSC, the European Union's Horizon 2020 research and innovation programme under grant agreement no 823852. M.U.K. and G.N. also acknowledge Project no. 2019-2.1.13-TÉT-IN-2020-00059 which has been implemented with the support provided from the National Research, Development and Innovation Fund of Hungary, financed under the 2019-2.1.13-TÉT-IN funding scheme. O.A.R. has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 899987. R.D.C. and L.M.C. acknowledge the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 956923

The role of the surface acidic/basic centers and redox sites on TiO2 in the photocatalytic CO2 reduction

The development of sustainable processes for CO reduction to fuels and chemicals is one of the most important challenges to provide clean energy solutions. The use of sunlight as renewable energy source is an interesting alternative to power the electron transfer required for artificial photosynthesis. Even if redox sites are mainly responsible for this process, other reactive acidic/basic centers also contribute to the overall reaction pathway. However, a full understanding of the CO photoreduction mechanism is still a scientific challenge. In fact, the lack of agreement on standardized comparison criteria leads to a wide distribution of reported productions, even using the same catalyst, which hinders a reliable interpretation. An additional difficulty is ascertaining the origin of carbon-containing products and effect of surface carbon residues, as well as the reaction intermediates and products under real dynamic conditions. To determine the elusive reaction mechanism, we report an interconnected strategy combining in-situ spectroscopies, theoretical studies and catalytic experiments. These studies show that CO photoreduction productions are influenced by the presence of carbon deposits (i.e. organic molecules, carbonates and bicarbonates) over the TiO surface. Most importantly, the acid/base character of the surface and the reaction medium play a key role in the selectivity and deactivation pathways. This TiO deactivation is mainly initiated by the formation of carbonates and peroxo- species, while activity can be partially recovered by a mild acid washing treatment. We anticipate that these findings and methodology enlighten the main shadows still covering the CO reduction mechanism, and, most importantly, provide essential clues for the design of emergent materials and reactions for photo(electro)catalytic energy conversion

Photoinduced Charge Transfer and Trapping on Single Gold Metal Nanoparticles on TiO2

We present a study of the effect of gold nanoparticles (Au NPs) on TiO2 on charge generation and trapping during illumination with photons of energy larger than the substrate band gap. We used a novel characterization technique, photoassisted Kelvin probe force microscopy, to study the process at the single Au NP level. We found that the photoinduced electron transfer from TiO2 to the Au NP increases logarithmically with light intensity due to the combined contribution of electron-hole pair generation in the space charge region in the TiO2-air interface and in the metal-semiconductor junction. Our measurements on single particles provide direct evidence for electron trapping that hinders electron-hole recombination, a key factor in the enhancement of photo(electro)catalytic activity.This work was supported by the Office of Basic Energy Sciences (BES) of the U.S. Department of Energy (DOE) under contract DE-AC02-05CH11231 through the Structure and Dynamics of Materials Interfaces Program (FWP KC31SM) and the Molecular Foundry. M.L. acknowledges funds from Comunidad de Madrid (P2018/EMT-4308), a Fulbright grant PRX16/00564, and the MCIU-AEI-FEDERUE (RTI2018-096937-B-C22 and MAT2014-59772-C2-1-P). J.C. acknowledges financial support from Ministerio de Ciencia e Innovación (MICINN) and the European Union through the project PID2019-104272RB-C52. Also, Y.H. acknowledges financial support from MCIU through MAT2014-59772-C2-2- P and L.M. from EC through ERC-2013-SYG-610256. V.A.P.O. and M.B. acknowledge the financial support from EC through ERC CoG HyMAP 648319, MINECO PID2019- 106315RB-I00 and ENE2017-89170-R, ″Comunidad de Madrid″ and European Structural Funds (FotoArt-CM project S2018/NMT-4367) and Fundación Ramón Areces (Art-Leaf project). M.B. also thanks the Juan de la Cierva Incorporación contract (IJC2019042430-I). X.Z. was supported by the NSF-BSF 359 grant number 1906014. The authors thank Prof. Eran Edri, María Ujué González Sagardoy, and Judit Meseguer- Oliver for fruitful discussions and Asylum customer support for help with modifications of the AFM

Highly Active and Stable Ni/La-Doped Ceria Material for Catalytic CO2Reduction by Reverse Water-Gas Shift Reaction

[EN] The design of an active, effective, and economically viable catalyst for CO2 conversion into value-added products is crucial in the fight against global warming and energy demand. We have developed very efficient catalysts for reverse water-gas shift (rWGS) reaction. Specific conditions of the synthesis by combustion allow the obtention of macroporous materials based on nanosized Ni particles supported on a mixed oxide of high purity and crystallinity. Here, we show that Ni/La-doped CeO2 catalysts─with the "right"Ni and La proportions─have an unprecedented catalytic performance per unit mass of catalyst for the rWGS reaction as the first step toward CO2 valorization. Correlations between physicochemical properties and catalytic activity, obtained using a combination of different techniques such as X-ray and neutron powder diffraction, Raman spectroscopy, in situ near ambient pressure X-ray photoelectron spectroscopy, electron microscopy, and catalytic testing, point out to optimum values for the Ni loading and the La proportion. Density functional theory calculations of elementary steps of the reaction on model Ni/ceria catalysts aid toward the microscopic understanding of the nature of the active sites. This finding offers a fundamental basis for developing economical catalysts that can be effectively used for CO2 reduction with hydrogen. A catalyst based on Ni0.07/(Ce0.9La0.1Ox)0.93 shows a CO production of 58 × 10-5 molCO·gcat-1·s-1 (700 °C, H2/CO2 = 2; selectivity to CO > 99.5), being stable for 100 h under continuous reaction.We acknowledge the financial support of the Spanish Ministry of Science and Innovation (PID2021-123287OB-I00, PID2021-122477-OB-I00, PID2021-128915NB-I00, and RTI2018-101604-B-I00) and of the CSIC through the i-LINK 2021 program (LINKA20408). Financial support has also been received from AEI-MINECO/FEDER (Nympha Project, PID2019-106315RB-I00), “Comunidad de Madrid” regional government, and the European Structural Funds (FotoArt-CM project, S2018/NMT-4367). Authors also acknowledge financial support from the grant PLEC2021-007906 funded by MCIN/AEI/10.13039/501100011033 and the “European Union NextGenerationEU/PRTR”. We are grateful to ILL (France) for making all facilities available. This project also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 832121. Computer time provided by the RES (Red Española de Supercomputación) resources at the MareNostrum 4 (BSC, Barcelona) node and the DECI resources at the BEM cluster of the WCSS based in Poland with the support from PRACE aislb is acknowledged

Highly Durable Nanoporous Cu2–xS Films for Efficient Hydrogen Evolution Electrocatalysis under Mild pH Conditions

Copper-based hydrogen evolution electrocatalysts are promising materials to scale-up hydrogen production due to their reported high current densities; however, electrode durability remains a challenge. Here, we report a facile, cost-effective, and scalable synthetic route to produce Cu2–xS electrocatalysts, exhibiting hydrogen evolution rates that increase for ∼1 month of operation. Our Cu2–xS electrodes reach a state-of-the-art performance of ∼400 mA cm–2 at −1 V vs RHE under mild conditions (pH 8.6), with almost 100% Faradaic efficiency for hydrogen evolution. The rise in current density was found to scale with the electrode electrochemically active surface area. The increased performance of our Cu2–xS electrodes correlates with a decrease in the Tafel slope, while analyses by X-ray photoemission spectroscopy, operando X-ray diffraction, and in situ spectroelectrochemistry cooperatively revealed the Cu-centered nature of the catalytically active species. These results allowed us to increase fundamental understanding of heterogeneous electrocatalyst transformation and consequent structure–activity relationship. This facile synthesis of highly durable and efficient Cu2–xS electrocatalysts enables the development of competitive electrodes for hydrogen evolution under mild pH conditions.Funding for open access charge: CRUE-Universitat Jaume IICN2 acknowledges funding from Generalitat de Catalunya 2021SGR00457. This study is part of the Advanced Materials programme and supported by MCIN with funding from European Union NextGenerationEU (PRTR-C17.I1), Generalitat de Catalunya, and the Basque Government (grant IT1591-22). The authors thank the support from the projects (RED2022-134508-T, PID2020-116093RB-C41, PID2020-116093RB-C43, and PID2020-116093RB-C44) funded by MCIN/AEI/10.13039/501100011033/ and the project TED2021-129999A-C33 financed by MCIN/AEI/10.13039/501100011033 and European Union NextGenerationEU/PRTR. C.A.M. acknowledges funding from UJI postdoc fellowship POSDOC/2019/20, the Generalitat Valenciana for the APOSTD/2021/251 fellowship, and to MinCiencias Colombia through the Fondo Nacional de Financiamiento para la Ciencia, la Tecnología y la Innovación “Francisco José de Caldas”, call 848-2019. ICN2 is supported by the Severo Ochoa program from Spanish MCIN/AEI (Grant No.: CEX2021-001214-S) and is funded by the CERCA Programme/Generalitat de Catalunya. M.C.S. has received funding from the post-doctoral fellowship Juan de la Cierva Incorporation from MICINN (JCI-2019) and the Severo Ochoa programme. S.B. acknowledges grant RYC-2017-21931 funded by MCIN/AEI/10.13039/501100011033 and by ESF Investing in Your Future, EUR2020-112066 funded by MCIN/AEI /10.13039/501100011033 and by European Union NextGenerationEU/PRTR, and UPV/EHU project EHUrOPE19/01. J.R. acknowledges the Czech Science Foundation and funding from PIF outgoing project number 22-18079O

Photo-Induced Self-Cleaning and Wettability in TiO2 Nanocolumn Arrays Obtained by Glancing-Angle Deposition with Sputtering

In this work, the preparation of regular nanosized columnar structures of titanium dioxide by means of glancing angle deposition with magnetron sputtering (MS-GLAD) followed by thermal annealing is reported. MS-GLAD gives rise to metallic titanium columnar structures with regular width and length that after thermal treatment are fully oxidized to form TiO2 nanocolumns that maintain the morphological features of the original metallic ones. Further functionalization with gold by means of multiple ion cluster source results in well-dispersed Au nanoparticles across the nanocolumns’ surface with a narrow size distribution centered at ca. 8.5 nm. The obtained nanostructures show photocatalytic self-cleaning activity as shown by the elimination of an organic layer deposited on their surface and the detection of hydroxyl radicals. Photoelectrochemical measurements show a better charge separation at the Au/TiO2 interface. In addition, wettability studies show that the degree of hydrophobicity of the surface is increased by the presence of nanocolumns, both in the dark and under UV illumination. This behavior is not modified by the presence of Au nanoparticles on the surface. The obtained results open up interesting implications in the tunability of the properties of nanostructured thin films for this kind of photo-activated application.Financial support from the Spanish Ministry of Science, Innovation, and Universities (MICINN) through the projects SOLPAC (ENE2017-89170-R, MCIU/AEI/FEDER, EU), MAT2014-59772-C2-1-P, and MAT2014-59772-C2-2-P is gratefully acknowledged. The authors also acknowledge the service from the MiNa Laboratory at IMN funded by Comunidad de Madrid (S2018/NMT-4291 TEC2SPACE), MICINN (CSIC13-4E-1794), and the EU (FEDER, FSE). Also, this work has been funded by the regional government of Madrid and European Structural Funds through their financial support to FotoArt-CM program (S2018/NMT-4367), and from Fundación Ramon Areces though the ArtLeaf project. M.B. thanks MICINN for a Juan de la Cierva Incorporación (IJC2019-042430-I) grant.Peer reviewe

Improved Methane Production by Photocatalytic CO2 Conversion over Ag/In2O3/TiO2 Heterojunctions

In this work, the role of In2O3 in a heterojunction with TiO2 is studied as a way of increasing the photocatalytic activity for gas-phase CO2 reduction using water as the electron donor and UV irradiation. Depending on the nature of the employed In2O3, different behaviors appear. Thus, with the high crystallite sizes of commercial In2O3, the activity is improved with respect to TiO2, with modest improvements in the selectivity to methane. On the other hand, when In2O3 obtained in the laboratory, with low crystallite size, is employed, there is a further change in selectivity toward CH4, even if the total conversion is lower than that obtained with TiO2. The selectivity improvement in the heterojunctions is attributed to an enhancement in the charge transfer and separation with the presence of In2O3, more pronounced when smaller particles are used as in the case of laboratory-made In2O3, as confirmed by time-resolved fluorescence measurements. Ternary systems formed by these heterojunctions with silver nanoparticles reflect a drastic change in selectivity toward methane, confirming the role of silver as an electron collector that favors the charge transfer to the reaction medium.This research was funded by the European Union’s Horizon 2020 research and innovation program under the European Research Council (ERC) through the HyMAP project, grant agreement No. 648319. Additional funding by the Spanish MCIN/AEI/10.13039/501100011033/FEDER through the Nympha Project (PID2019-106315RB-I00), the regional government of “Comunidad de Madrid” and the European Structural Funds through FotoArt-CM program (S2018/NMT-4367), and Fundación Ramón Areces through the ArtLeaf project is gratefully acknowledged.Peer reviewe

Material órgano-inorgánico microporoso cristalino basado en cationes alcalinotérreos, procedimiento de preparación y usos

Material órgano-inorgánico microporoso cristalino basado en cationes alcalinotérreos, procedimiento de preparación y usos. La presente invención se refiere a una familia de materiales órgano-inorgánicos microporosos cristalinos conteniendo cationes alcalinotérreos y ácidos dicarboxílicos, su procedimiento de preparación y su uso como catalizadores heterogéneos reutilizables para reacciones en química orgánica, como tamices moleculares y como absorbentes de gases y líquidos.Peer reviewedConsejo Superior de Investigaciones Científicas (España), Instituto Madrileño de Estudios Avanzados en Energía (IMDEA-ENERGÍA)A1 Solicitud de patentes con informe sobre el estado de la técnic