Chinese Journal of Catalysis ›› 2026, Vol. 80: 146-158.DOI: 10.1016/S1872-2067(25)64857-1

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Synergetic photocatalytic H2 evolution and H2S conversion over S-scheme Co3(PO4)2/CoSx/twinned-Cd0.5Zn0.5S

Xinyi Maa, Ziyi Xiaoa, Xueqing Hua, Haobin Hub,*(), Wenhua Xuec,*(), Enzhou Liua,*()   

  1. aSchool of Chemical Engineering/Xi’an Key Laboratory of Special Energy Materials, Northwest University, Xi’an 710069, Shaanxi, China
    bGansu Key Laboratory of Efficient Utilization of Oil and Gas Resources in Longdong, Longdong University, Qingyang 745000, Gansu, China
    cResearch Center for Eco-Environmental Engineering, Dongguan University of Technology, Dongguan 523808, Guangdong, China
  • Received:2025-07-16 Accepted:2025-08-25 Online:2026-01-18 Published:2026-01-05
  • Contact: Haobin Hu, Wenhua Xue, Enzhou Liu
  • Supported by:
    Guiding Funds of Central Government for Supporting the Development of the Local Science and Technology(24ZYQM001);National Natural Science Foundation of China(22378326);Natural Science Basic Research Program of Shaanxi Province(2023-JC-YB-115)

Abstract:

Developing sustainable, low-cost H2S conversion technologies holds significant importance for the coal chemical and petrochemical industries. Herein, twinned Cd0.5Zn0.5S (T-CZS) homojunctions serve as model photocatalysts, with a Na2S/NaH2PO2 solution simulating H2S absorption to regulate S2−/HS transformation pathways for concurrent efficient H2 evolution and desulfurization. Notably, at 3 mol∙L−1 NaH2PO2 concentration, the H2 evolution rate (rH2) over T-CZS reaches 233.9 mmol∙g−1∙h−1—representing a 5.5-fold enhancement versus 0.1 mol∙L−1 Na2S alone. Mechanistic studies reveal that the two-step oxidation of H2PO2 delivers four electrons for H+ reduction while simultaneously scavenging deleterious S22− species. This dual function mitigates light-absorption competition, enhances interfacial electron density, and accelerates H2-evolution kinetics. Further, Co3(PO4)2/CoSx loading boosts H2 production to 292.1 mmol∙g−1∙h−1, primarily ascribed to suppressed bulk/interface charge recombination. Crucially, acidification of post-reaction solutions yields pure elemental sulfur (S) as a yellow solid. Practical viability was validated using H2S preparation and absorption system, confirming robust catalyst performance and system efficacy for integrated high-efficiency H2 production and S recovery. The critical role and significant potential of H2PO2 in enhancing H2 evolution in S2−/HS solutions were emphasized, offering potential strategies for efficient photocatalytic conversion of S2−/HS. This work establishes a new paradigm for green, economical H2S valorization.

Key words: Photocatalyst, Desulfurization, Conversion of S2?/HS?, Twinned-Cd0.5Zn0.5S, Homo-heterojunction