Two-Dimensional S-Scheme Engineering in Bi<sub>2</sub>WO<sub>6</sub>/S<sub>V</sub>-ZnIn<sub>2</sub>S<sub>4</sub> for Solar-Driven H<sub>2</sub>O<sub>2</sub> Generation in Pure Water
Muhammad Adnan Qaiser, Shahid Ullah Khan, Haopeng Jiang, Jinhe Li, Syed Bilal Ahmed, Waqar Ahmad Qureshi, Syed Najeeb-uz Zaman Haider, Weikang Wang, Qinqin Liu
Abstract
The development of eco-friendly hydrogen peroxide (H 2 O 2 ) synthesis through the photocatalytic oxygen reduction reaction holds significant potential for sustainable chemical engineering; however, it remains hindered by the necessity of sacrificial agents. Herein, we construct a two-dimensional (2D) S-scheme heterojunction through interfacial coupling of S-vacancy-rich ZnIn 2 S 4 (S V -ZIS) with Bi 2 WO 6 (BWO) nanosheets via an in situ growth method. Band alignment engineering establishes a giant built-in electric field at the Bi 2 WO 6 /S V -ZIS interface, which drives directional S-scheme charge transfer, leaving the photogenerated electrons and holes with the highest redox potentials accumulated on BWO and S V -ZIS, respectively, for O 2 reduction and H 2 O oxidation. This spatial separation mechanism enhances both electron–hole pair dissociation efficiency (validated by transient photocurrent analysis) and preserves strong redox potentials (reflected in free-radical capturing experiments). The 2D/2D architecture further amplifies interfacial charge migration through atomic-level contact, leading to an efficient H 2 O 2 production rate of 822 μmol L –1 h –1 in pure water. This work provides a two-dimensional S-scheme engineering strategy for designing high-performance photocatalysts toward sustainable H 2 O 2 synthesis under environmentally benign conditions.