Photoelectrocatalytic performance of nanostructured p-n junction NtTiO₂/NsCuO electrode in the selective conversion of CO₂ to methanol at low bias potentials

Autor(es)

de Brito, Juliana Ferreira ; Hudari, Felipe Fantinato ; Boldrin Zanoni, Maria Valnice

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF CO2 UTILIZATION; v. 24, p. 8-pg., 2018-03-01.

Resumo

Aiming a selective reduction of CO2 to methanol, a p-n junction semiconductor was constructed based on CuO nanospheres (NsCuO) deposited at TiO2 nanotubes (NtTiO(2)). The NtTiO(2)/NsCuO material demonstrated smaller charge transfer resistance, smaller flat band potential and wider optical absorption when compared with NtTiO(2) and/or Ti/TiO2 nanoparticles coated by higher size particles of CuO (Ti/TiO2/CuO). The selective reduction of dissolved CO2 to methanol was promoted at lower potential of +0.2 V and UV-vis irradiation in 0.1 mol L-1 K2SO4 electrolyte pH 8 with 57% of faradaic efficiency. Even though the performance of the nanostructured material NtTiO(2)/NsCuO was similar to the non-completely nanostructured material Ti/TiO2/CuO (0.1 mmol methanol), the conversion to methanol has been significantly increased when hydroxyls (0.62 mmol L-1) and holes scavengers (0.71 mmol L-1), such as p-nitrosodimethylaniline (RNO) or glucose, respectively, were added in the supporting electrolyte. It indicates that photogenerated electron/hole pairs are spatially separated on p-n junction electrodes, which produces effective electrons and long-life holes, influencing the products formed in the reaction. A schematic representation of the heterojunction effect on the photoelectrocatalytic CO2 reduction is proposed under the semiconductor and each supporting electrolyte, which improves the knowledge about the subject. (AU)

• Processo FAPESP: 08/10449-7 - Avaliação da ocorrência, toxicidade/genotoxicidade e processos para degradação de corantes em efluentes e águas superficiais
• Beneficiário: Maria Valnice Boldrin
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 13/25343-8 - Oxidação Simultânea de Compostos Orgânicos da Água Residual de Petróleo e Redução de CO2 Dissolvido por Fotoeletrocatálise
• Beneficiário: Juliana Ferreira de Brito
• Modalidade de apoio: Bolsas no Brasil - Doutorado