Shengming Xu,Jing Xu,Jiandong Wu,Zhengyang Zhou,Bixian Wang,Tianlan Lan
The development of photocatalysts with efficient hydrogen evolution activity has been the goal for sustainable hydrogen production . In this work, heterojunction composite photocatalyst is formed by hydrothermal coupling of ZnO and Mn 0.2 Cd 0.8 S. Compared with pure ZnO and Mn 0.2 Cd 0.8 S, the composite photocatalyst has the ability to provide more abundant active sites and better photogenerated carriers separation efficiency. The optimized composite photocatalyst shows a 9.36-fold increase in hydrogen evolution activity (4297.99 μmol g −1 h −1 ) compared to Mn 0.2 Cd 0.8 S (459.31 μmol g −1 h −1 ) and exhibits excellent cycling stability. Density functional theory calculations identifies Type-II charge transfer path in the composite photocatalyst, achieving effective separation in space of photogenerated electrons from holes and suppressing recombination within the semiconductor. The results show that the construction of Type-II heterojunction in this work achieves a significant enhancement of the hydrogen evolution activity of the photocatalyst by constructing carrier transport channels at the contact interface of the heterojunction.
Photocatalytic hydrogen peroxide (H 2 O 2 ) synthesis in pure water (H 2 O) is challenging because it requires simultaneous efficient charge separation and selective two-electron oxygen reduction. Herein, we report an S-scheme Mn 0.2 Cd 0.8 S/ZnIn 2 S 4 (MZ) heterojunction that synergistically regulates interfacial charge flow and surface oxygen (O 2 ) adsorption configuration. The optimized MZ-15 achieves a H 2 O 2 production rate of 3917.3 μmol g −1 h −1 in pure water without sacrificial agents. The S-scheme pathway promotes charge separation while preserving strong redox capability. More importantly, the pronounced ionic-radius mismatch between Mn 2+ and Cd 2+ in Mn 0.2 Cd 0.8 S induces an asymmetric electronic environment that shifts O 2 adsorption from side-on to end-on (Pauling-type) configuration, thereby favoring O O bond retention and two-electron oxygen reduction reaction (2e − ORR). This work highlights that simultaneous engineering of interfacial charge dynamics and O 2 adsorption geometry is a powerful strategy for highly selective photocatalytic H 2 O 2 production An S-scheme Mn 0.2 Cd 0.8 S/ZnIn 2 S 4 heterojunction achieves coupled interfacial charge-flow engineering and Pauling-type O 2 adsorption to realize selective 2e⁻ ORR for H 2 O 2 production in sacrificial‑agent‑free pure water. Download: Download high-res image (187KB) Download: Download full-size image
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