Rational Engineering of S-Scheme Nb2O5/Bi2WO6 Heterojunction: Achieving 4525 μmol g−1 h−1 of Photosynthesis of Hydrogen Peroxide

Abstract

Developing efficient semiconductor catalysts for the photocatalytic synthesis of hydrogen peroxide remains intrinsically challenging, primarily because the rapid recombination of photoinduced charge carriers limits reaction efficiency. In this work, an S-scheme Nb₂O₅/Bi₂WO₆ (Nb/BiW) heterojunction is rationally engineered to overcome these intrinsic limitations and markedly enhance photoinduced charge separation. Systematic experimental investigations demonstrate that integrating Nb₂O₅ with Bi₂WO₆ broadens light-harvesting capability, increases accessible surface area, and creates abundant interfacial charge transport channels, thereby facilitating efficient carrier migration and providing a high density of redox-active sites. The optimized Nb/BiW-1.5 heterojunction exhibits superior photocatalytic performance, delivering an H₂O₂ production rate of 4525 μmol g⁻¹ h⁻¹ within 60 min under simulated solar irradiation (AM 1.5). In parallel, the catalyst maintains excellent durability, sustaining catalytic efficiency over 10 successive reaction cycles. Mechanistic analysis, supported by comprehensive physicochemical characterizations and control experiments, reveals that the built-in internal electric field inherent to the S-scheme junction plays a pivotal role in directing charge separation and transfer while preserving strong redox potentials. These findings elucidate fundamental aspects of H₂O₂ photosynthesis in Nb/BiW systems and provide a general design framework for next-generation photocatalysts for solar-driven chemical synthesis.