Experimental and theoretical studies of WO₃/Vulcan XC-72 electrocatalyst enhanced H₂O₂ yield ORR performed in acid and alkaline medium

Author(s)

Moura, Joao Paulo C. ; Lucchetti, Lanna E. B. ; Fernandes, Caio M. ; Trench, Aline B. ; Lange, Camila N. ; Batista, Bruno L. ; Almeida, James M. ; Santos, Mauro C.

• Document type: Journal article
• Source: JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING; v. 12, n. 4, p. 11-pg., 2024-06-07.

Abstract

The oxygen reduction reaction (ORR) plays a pivotal role in clean energy generation and sustainable chemical production, particularly in the synthesis of hydrogen peroxide (H2O2). In this study, WO3/Vulcan-XC72 electrocatalysts have been synthesized and characterized for ORR applications. We assessed the ratio of WO3 to Vulcan-XC72 and investigated the impact of electrolytes pH (covering acidic and alkaline media) on the ORR process. The results revealed that WO3 with a monoclinic crystalline phase and nanoflower-like morphology was successfully synthesized, and confirmed an improvement in surface properties, with an increase in hydrophilicity and superficial oxygenated species. Electrochemical studies showed that WO3/C was the most selective for H2O2 electrogeneration, compared to pure Vulcan-XC72, in both acidic and alkaline media. These results indicate that the ORR on the WO3/C electrocatalyst surface has a pH-dependent mechanism. Using WO3/C GDEs, an accumulation of 862 mg L-1 of H2O2 was achieved after 120 min of electrolysis at 100 mA cm-2. The higher selectivity of WO3/C could be related to the presence of more oxygen functional acid species on the catalyst surface and increased hydrophilicity compared to pure Vulcan, as well as a synergistic effect of the WO3 nanoflowers in ORR, confirmed by theoretical calculations. The results reveal that WO3/Vulcan is a promising catalyst for H2O2 electrogeneration via the ORR. (AU)

• FAPESP's process: 22/15252-4 - Nanostructured electrocatalysts for application in direct alkaline-acid fuel cells of glycerol
• Grantee: Mauro Coelho dos Santos
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Regular Program Grants
• FAPESP's process: 21/14394-7 - Use of Vulcan XC-72 carbon modified with fluorine and/or cerium doped niobium nanostructures in the electrogeneration of H2O2 for degradation of endocrine disruptors by advanced electrochemical oxidative processes
• Grantee: Aline Barrios Trench
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 21/05364-7 - Nanostructured electrocatalysts based on manganese and tungsten oxides supported on carbon for electrogeneration of hydrogen peroxide and electrochemical degradation of ciprofloxacino
• Grantee: João Paulo Carvalho Moura
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 22/12895-1 - Advanced processes for the degradation of emerging pollutants: catalytic materials, electroanalytical sensors and scientific dissemination
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/10118-0 - Study and application of electrochemical technology for the analysis and degradation of endocrine interferents: materials, sensors, processes and scientific dissemination
• Grantee: Marcos Roberto de Vasconcelos Lanza
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 22/10484-4 - Application of low-cost nanomaterials for degradation of endocrine disruptors through advanced electrochemical oxidation processes under the influence of a magnetic field
• Grantee: Caio Machado Fernandes
• Support Opportunities: Scholarships in Brazil - Post-Doctoral