Building hollow multi-shell structured Zn2MnO4/CdS S-scheme heterojunction for boosted photocatalytic H2 production

Abstract

Building an S-scheme heterojunction photocatalyst with a hollow multi-shell structure is regarded as of great significance to realize efficient H₂ production. Herein, a hollow multi-shell structured Zn₂MnO₄/CdS S-scheme heterojunction photocatalyst was successfully constructed via a coordination polymer self-assembly strategy combined with non-uniform shrinkage effect and subsequent hydrothermal treatment. In the unique heterojunction system, the hollow multi-shell structure bestows significant merits upon the design of photocatalysts for boosted photocatalytic H₂ production, including enhanced light capture ability, shortened photo-induced charge transfer distance, and provides abundant reactive sites. Simultaneously, the S-scheme mechanism not only promotes the separation and migration of photo-induced charge, but also additionally maintains the strong redox ability. As a result, Zn₂MnO₄/CdS heterojunction displays an unparalleled photocatalytic H₂ production rate of 22.42 mmol g^-1 h^-1, almost 10.99 and 35.03 times that of pure Zn₂MnO₄ and CdS, respectively. Simultaneously, the heterojunction also demonstrates outstanding cycling stability, with no significant decline in photocatalytic H₂ production activity after 10 cycles. Furthermore, the in-situ irradiated X-ray photoelectron spectroscopy and electron paramagnetic resonance spectroscopy further verify the S-scheme charge transfer pathway in Zn₂MnO₄/CdS heterojunction. Our study proposes an innovative viewpoint of hollow multi-shell structured S-scheme heterojunction photocatalyst for solar-driven H₂ production.