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

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 (H\textsubscript{2}O\textsubscript{2}). In this study, WO\textsubscript{3}/Vulcan-XC72 electrocatalysts were synthesized and characterized for ORR applications, evaluating the WO\textsubscript{3} to Vulcan-XC72 ratio and examining electrolyte pH effects across acidic and alkaline media. Structural characterization confirmed successful synthesis of monoclinic WO\textsubscript{3} with nanoflower morphology, which enhanced surface hydrophilicity and oxygen functional groups. Electrochemical tests demonstrated WO\textsubscript{3}/C's superior H\textsubscript{2}O\textsubscript{2} selectivity compared to pure Vulcan-XC72 in both media, revealing a pH-dependent ORR mechanism. Using WO\textsubscript{3}/C gas diffusion electrodes (GDEs), we achieved 862,mg,L\textsuperscript{-1} H\textsubscript{2}O\textsubscript{2} accumulation after 120,min at 100,mA,cm\textsuperscript{-2}. The enhanced performance stems from increased oxygen functional groups, improved hydrophilicity, and WO\textsubscript{3} nanoflower synergistic effects, as supported by theoretical calculations, establishing WO\textsubscript{3}/Vulcan as a promising catalyst for electrochemical H\textsubscript{2}O\textsubscript{2} production.