Development of CuWO4/CuWO4-x homojunctions and optimization of CuWO4 films for H2 photogeneration and pollutant photodegradation

• Grant number: 22/06542-9
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: April 01, 2023
• End date: March 01, 2027
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Jose Humberto Dias da Silva
• Grantee: Lucas Caniati Escaliante
• Host Institution: Faculdade de Ciências (FC). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil
• Associated scholarship(s): 23/04793-7 - Composition and surface modifications of CuWO4 photoelectrodes for enhancing the efficiency of oxygen evolution reaction, BE.EP.DR

Abstract

Copper tungstate (CuWO4) is a 2.3 eV bandgap semiconductor used in lithium batteries, sensors, and also in photoelectrochemical (PEC) and photocatalytic (PC) applications. Materials for PEC and PC application need to be optimised, for example in terms of electrical responses such as photocurrent and photovoltage. This optimization involves their surfaces and interfaces with the electrolytes and the situation become more complex by the fact that the charge transfer processes at the interfaces occur in the presence of light. In this context, it is proposed here the deposition, optimization of CuWO4 films and CuWO4/CuWO4-x homojunctions and investigation of the charge transfer processes between the films and electrolyte in the dark and in the presence of light. The aim is to optimize the composition of materials and their efficiency in photoelectrochemical processes, generating H2, and photocatalytic, and to degrade pollutants, both using sunlight. The films will be grown using the reactive co-sputtering technique, in which depositions will be made with two metallic targets (Cu and W), operating simultaneously, providing greater control of the deposited metals in addition to depositions under the modulation regime of the O2 flow for the purpose of creating CuWO4/CuWO4-x homojunctions. These layers create donor states and produce modulations at the Fermi level of the material, which can favor the separation between photogenerated carriers, increasing the efficiency of the devices. The research has an internship at the Osterloh laboratory, University of California - Davis, where there will be the photoelectrochemical characterization of the devices, in addition to surface potential measurements, analyzing the photoinduced charge transfer processes and the efficiency of CuWO4 photoelectrodes for H2 generation

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

ESCALIANTE, LUCAS CANIATI; AZEVEDO NETO, NILTON FRANCELOSI; MENDOZA, HERVIN ERROL; XIAO, CHENGCAN; KANDEL, RAJESH; DA SILVA, JOSE HUMBERTO DIAS; OSTERLOH, FRANK E.. Sputter-Coated TiO₂ Films as Passivation and Hole Transfer Layers for Improved Energy Conversion with Solar Fuel WO₃/CuWO₄ Photoanodes. ACS APPLIED MATERIALS & INTERFACES, v. 16, n. 50, p. 10-pg., 2024-12-03. (23/04793-7, 22/06542-9)

ESCALIANTE, LUCAS CANIATI; NETO, NILTON FRANCELOSI AZEVEDO; MENDOZA, HERVIN ERROL; XIAO, CHENGCAN; KANDEL, RAJESH; DA SILVA, JOSE HUMBERTO DIAS; OSTERLOH, FRANK E.. WO₃/CuWO₄ Ratio Controls Open-Circuit Photovoltage and Photocurrent in Type II Heterojunction Solar Fuel Photoelectrodes. ACS APPLIED ENERGY MATERIALS, v. N/A, p. 11-pg., 2025-02-19. (23/04793-7, 22/06542-9)