In situ analysis of surface intermediates on (W)BiVO4/WO3 photoanodes using a combined scanning electrochemical microscopy approach

• Grant number: 19/00904-3
• Support type: Scholarships abroad - Research Internship - Master's degree
• Effective date (Start): May 01, 2019
• Effective date (End): October 31, 2019
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal researcher: Juliana dos Santos de Souza
• Grantee: Bárbara Scola Rodrigues
• Supervisor abroad: Joaquín Rodríguez López
• Home Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil
• Research place: University of Illinois at Urbana-Champaign, United States
• Associated to the scholarship: 17/26633-0 - Microwave-assisted synthesis of bismuth vanadate and tungsten oxide nanostructures with application in photoelectrochemical water splitting, BP.MS

Abstract

Hydrogen is considered the fuel of the future, thus, the development of devices capable of generating this species are particularly interesting. Among the possible strategies to achieve this goal, the development of photoanodes for photoelectrochemical water splitting, to obtain H2 an O2, using simulated sunlight as energy source have emerged as attractive fundamental platforms for creating renewable technologies. Semiconductors oxides have been largely employed to develop this kind of devices, with special interest in those that absorb the visible component of the electromagnetic spectrum, which is the major portion of sunlight. Bismuth vanadate (BiVO4) and tungsten-doped BiVO4 (WBiVO4) are extremely promising materials, due to their physical-chemical properties and low band-gap energy (~ 2.4 eV). Tungsten trioxide is also highly adequate, exhibiting band-gap energy of approximately 2.8 eV. However, these two materials exhibit properties that limit their applicability for photoelectrochemical water splitting. On the other hand, the (W)BiVO4/WO3 heterojunction exhibit a synergic effect that mitigate these drawbacks making this and almost ideal combination for water photo splitting. However, the photoelectrochemical mechanism seems to be dependent on the heterojunction properties, which affects the surface species generated during the operation.Thus, the present project aims to elucidate the photocatalytic mechanism differences of (W)BiVO4/WO3 heterojunctions with different nanostructures morphologies, amount of dopant and BiVO4/WO3 ratios, using in situ and in operando schemes. These experiments will be conducted using scanning electrochemical microscopy (SECM) and surface interrogation scanning electrochemical microscopy (SI-SECM) combined to light irradiation and Raman spectroscopy. (AU)