Boosting Electrocatalytic H2O2 Production via Two-Electron Water Oxidation Driven by the Solid-Solution Effect in Bi2Mo x W1− x O6 Hollow Nanostructures

Abstract The electrochemical two-electron water oxidation reaction (2e−-WOR) offers a sustainable route for on-site H2O2 production, yet developing efficient and stable electrocatalysts remains challenging. Herein, cation-ratio engineering is employed to tune the performance of hollow-structured Bi2MoxW1−xO6 solid solutions. The optimal Bi2Mo0.5W0.5O6 exhibits a superior H2O2 production rate (5.99 μmol min−1 cm−2) and Faradaic efficiency (20.18%) at 2.6 V, significantly outperforming the end members. Enhanced activity originates from the solid-solution effect, which promotes electron transfer from WO6 to MoO6 units, upshifts the O 2p band center, and facilitates oxygen vacancy formation, thereby favoring the 2e−-WOR pathway. Post-stability characterization confirms preserved bulk structure alongside substantial metal leaching and oxygen vacancy accumulation. This work highlights Bi2Mo0.5W0.5O6 as a promising catalyst and demonstrates the effectiveness of cation-ratio tuning in designing complex oxide electrocatalysts.