CuxO and carbon-modified TiO2-based hybrid materials for photocatalytically assisted H-2 generation


Hydrogen, as an energy carrier, is a zero-emission fuel. Being green and clean, it is considered to play an important role in energy and environmental issues. Photocatalytic water splitting is a process used to generate hydrogen from the dissociation of water. Titanium dioxide is the archetype material for photocatalytic water splitting. However, because of the fast recombination of the photo-generated exciton, the yield of the reaction is typically low. To overcome this limit, in this work, the surface of the TiO2 nanoparticles was modified with copper and graphene to give hybrid nanostructures. Synthesized materials were tested in the photocatalytic hydrogen generation using methanol as the sacrificial agent. X-ray diffraction and spectroscopic results showed that copper did not enter the TiO2 structure, and that neither copper nor graphene substantially altered the optical band-gap of prepared photocatalysts. Detailed aberration-corrected high-resolution electron transmission electron imaging and spatially resolved energy-loss spectroscopy experiments showed the oxidation and amorphization of graphene nanoplatelets, probably due to the combined action of the acidic media of the solution with the thermal treatment necessary to produce the hybrid materials. Hydrogen generation from methanol/water mix proved that exists an optimum concentration of both copper and graphene (i.e. 0.5 mol% copper plus 0.5 wt% graphene) to grant a two-fold increase in hydrogen production compared with that of unmodified titania when using UVA irradiation. A higher amount of initial graphene (i.e. 1.0 wt% graphene and 0.5 mol% copper) was instead necessary for granting higher H-2 generation on visible-light exposure. Hybrid materials based on titania modified with both copper oxide and carbon-based materials could therefore be exploited as ideal candidates for light-to-energy applications. (C) 2020 Elsevier Ltd. All rights reserved.




Chemistry, Physical; Energy & Fuels; Materials Science, Multidisciplinary


Tobaldi, DM; Koci, K; Edelmannova, M; Lajaunie, L; Figueiredo, B; Calvino, JJ; Seabra, MP; Labrincha, JA

nossos autores


This work was partly developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Part-nership Agreement. David Maria Tobaldi is overly grateful to FCT and Portuguese national funds (OE) , through FCT, I.P., 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. The work was supported from ERDF 'Institute of Environmental Technology-Excellent Research' (No. CZ.02.1.01/0.0/0.0/16_019/000 0853) and using Large Research Infrastructure ENREGAT supported by the Ministry of Education, Youth and Sports of the Czech Republic under project No. LM2018098.' Luc Lajaunie gratefully acknowledges the support from the Spanish Ministerio de Economia y Competitividad (PID2019-107578GA-I0 0) . Authors wish to thank the European Structural and Investment Funds in the FEDER component, through the Operational Programme for Competitiveness and Internation-alization (COMPETE 2020) under the Project GNESISGraphenest's New Engineered System and its Implementation Solutions-Funding Reference: POCI010247FEDER033566, European Regional Development Fund. This project also received partial funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 823717ESTEEM3. Prof Libor C?apek (University of Pardubice, CZ) , and Prof C?edric Pardanaud (Aix-Marseille University, FR) are gratefully acknowl-edged for fruitful discussions. Lastly, still not less importantly, we are very much obliged to Miss Dafne Maria Glaglanon for proof-editing the English of the manuscript.

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