Gas diffusion photoelectrodes with copper tungstates for application on photoassisted CO2 reduction reaction

• Grant number: 21/05853-8
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Effective date (Start): December 01, 2021
• Effective date (End): February 28, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Claudia Longo
• Grantee: Jessica Costa Alvim
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Host Company: Universidade Estadual de Campinas (UNICAMP). Instituto de Química (IQ)
• Associated research grant: 17/11986-5 - Research Division 1 - Dense Energy Carriers, AP.PCPE

Abstract

The conversion of CO2 to hydrocarbons, alcohols or other high Density Energy Carriers (DEC) has been considered a hot topic of academic, technological and environmental interests. The CO2 reduction reaction (CO2RR) to obtain value-added products can be performed through electrolysis of aqueous solution containing dissolved CO2. However, the challenges include the energetic cost for electrolysis, the low CO2 solubility in aqueous media and also, the low faradaic efficiency due concomitant hydrogen evolution reaction. We have been investigating photoelectrodes for CO2RR in our Research Group, at scope of DEC division of CINE, in collaboration with researchers from USA and United Kingdom. Our studies revealed that copper tungstates with mixed valence, Cu (I) and Cu (II), behave as p-type semiconductors and are photoactive for CO2RR; however, such materials still remains unstable for application as photocathodes for CO2RR. This project for a Direct Doctorate (DD) fellowship (which was initiated as a MsC in March/2020) aims to develop Gas Diffusion Electrodes (GDE) with copper tungstates for application on photoassisted CO2 reduction reaction. The plan of activities to achieve the objectives includes (I) preparation and characterization of copper tungstates electrodes; (II) investigation of processes involved in the Cu (I) to Cu (II) transition; (III) photocatalyst immobilization on GDE surface; (IV) identification and quantification of products generated from electrolysis for photoassisted CO2RR; (V) evaluation of co-catalysts for CO2RR (metallic nanoparticles and carbonaceous materials) and protective layer against photocorrosion (e.g. TiO2 and aminosilanes) to improve the stability, efficiency and selectivity of electrode for DEC production. As this project combines strategies to use and convert solar energy (which can reduce the cost of electrolysis) and minimize the problems from low solubility of CO2 in water its development will can contribute to further understanding the properties of copper tungstates and RRCO2, as well it will contribute to development of efficient and sustainable electrolysers for CO2 conversion. (AU)