Ternary Oxide CuWO4/BiVO4/FeCoOx Films for Photoelectrochemical Water Oxidation: Insights into the Electronic Structure and Interfacial Band Alignment

Autor(es)

Rosa, Washington S. ; Rabelo, Lucas G. ; Tiveron Zampaulo, Luis Gustavo ; Goncalves, Renato, V

• Tipo de documento: Artigo Científico
• Fonte: ACS APPLIED MATERIALS & INTERFACES; v. 14, n. 20, p. 12-pg., 2022-01-12.

Resumo

Photoelectrochemical (PEC) water oxidation using ternary oxide systems has been considered a promising approach for investigating the effective utilization of sunlight and the production of green fuel. Herein, we report a ternary-oxide-based CuWO4/BiVO4/FeCoOx film deposited entirely by RF-magnetron sputtering using homemade ceramic targets. Our CuWO4/BiVO4 photoanode exhibits a significant photocurrent density of 0.82 mA cm(-2) at 1.23 V vs RHE under AM 1.5G illumination, which is a record 382% increase compared to that of the bare CuWO4 film. To further boost the PEC performance, we deposited an ultrathin layer of amorphous FeCoOx cocatalyst, resulting in a triple CuWO4/BiVO4/FeCoOx heterojunction with a significant reduction in onset potential and a 500% increase in the photocurrent density of bare CuWO4. Experimental and theoretical approaches were used to provide insights into the interfacial band alignment and photoinduced charge carrier pathway across heterojunctions. Our results reveal noticeable interface potential barriers for charge carriers at the CuWO4/BiVO4 heterojunction, potentially limiting its application in tandem systems. Conversely, the deposition of the FeCoOx ultrathin layer over the CuWO4/BiVO4 heterojunction induces a p-n junction on the BiVO4/FeCoOx interface, which, when combined with the abundant FeCoOx oxygen vacancies, results in improved charge separation and transport as well as enhanced photoelectrochemical stability. Our study provides a feasible strategy for producing photocatalytic heterojunction systems and introduces simple tools for investigating interface effects on photoinduced charge carrier pathways for PEC water splitting. (AU)

• Processo FAPESP: 19/18724-1 - Desenvolvimento de filmes de CuWO4 e estudo das propriedades eletrônicas para aplicação na fotossíntese artificial
• Beneficiário: Lucas Gabriel Rabelo
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 19/15434-2 - Integração das estratégias de síntese para melhorar o transporte de portadores de cargas e eficiência do BiVO4 aplicado na fotossíntese artificial sob luz solar
• Beneficiário: Renato Vitalino Gonçalves
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 17/18716-3 - Fotossíntese artificial: desenvolvimento de sistemas Tandem para a produção de hidrogênio combustível a partir da água e luz solar
• Beneficiário: Renato Vitalino Gonçalves
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores