Romeiro, F. C. [UNESP]Silva, B. C. [UNESP]Martins, A. S. [UNESP]Zanoni, M. V.B. [UNESP]Orlandi, M. O. [UNESP]2021-06-252021-06-252021-04-01Journal of CO2 Utilization, v. 46.2212-9820http://hdl.handle.net/11449/205901This study reports on the photoelectrochemical reduction of CO2 to methanol using Sn3O4 and reduced graphene oxide-tin oxide (rGO-Sn) nanocomposite synthesized through the microwave-assisted hydrothermal method. The resulting rGO-Sn nanocomposite exhibited enhanced activity and good stability during photoelectrochemical CO2 reduction explained by Z-scheme electron transport. Graphene oxide (GO) has played a crucial role in the chemical composition and morphology of nanocomposites. The interaction between GO and Sn2+ ions during synthesis promoted the formation of the SnO2 phase in the nanocomposite, thus generating mixed rGO/Sn3O4/SnO2 phases (the rGO-Sn nanocomposite). Remarkable selectivity for CO2/methanol conversion was obtained for both Sn3O4 and the nanocomposite at different potentials, in which the nanocomposite presented the highest conversion to methanol with a faradaic efficiency of 45 % at -0.3 V vs. Ag/AgCl. The improved activity of the nanocomposite was ascribed to the efficient use of solar energy (UV + visible light), to the decrease in electronic recombination in nanocomposite, which enabled an efficient electron-hole separation on the surface of the nanocomposite, and to the presence of rGO being combined with Sn3O4 and SnO2 structures, which ensured a faster charge transport rate. This study reveals the potential of rGO-Sn nanocomposites as photocathodic material for solar-to-chemical energy conversion.engCO2reductionMicrowave-assisted hydrothermal methodPhotoelectrochemical propertiesReduced graphene oxideSn3O4Artigo10.1016/j.jcou.2021.1014602-s2.0-85101071319