Abstract
The utilization of renewable energy for sustainable hydrogen production has gained significant attention. Photocatalytic water splitting has emerged as a viable method; however, the performance of photocatalysts is constrained by weak visible light absorption, and inefficient charge carrier separation and transfer. This research investigated modifying metal sulfide derived from MOFs and combining metal sulfide with MOF-derived oxide to address these limitations for enhanced activity for photocatalytic hydrogen evolution.This research initially studied the synthesis of metal sulfide-based photocatalysts from MOF precursors and their use in the hydrogen evolution reaction. A series of MOF-derived In₂S₃ photocatalysts were investigated, elucidating the impact of different types and densities of defects on promoting visible light-driven hydrogen generation. Characterizations show how defects affect In₂S₃'s structural, morphological, and electrical properties, revealing ways to improve photocatalytic activity.
The above study explored the feasibility of MOF-derived metal sulfide for HER. Based on it, the second study focused on improving the performance of MOF-derived metal sulfide by developing composite materials in heterojunction to enhance charge carriers’ separation and transfer efficiency. A novel synthesis route was developed to fabricate MOF-derived Co₃S₄ and ZnIn₂S₄ photocatalysts, and the constructed Z-scheme heterojunction significantly enhancing hydrogen generation efficiency compared with single MOF-derived metal sulfide.
To further enhance the performance of the photocatalyst, incorporating a photocatalyst with superior visible light absorption capability was applied. The third study monitored the synthesis of MOF-derived oxides with strong visible light absorption and established a Z-scheme heterojunction. The structure of the MOF-derived Co₃O₄/ZnIn₂S₄ Z-scheme heterostructure considerably increased vision-driven hydrogen generation also via the internal electric field. Investigating the formation mechanism and photocatalytic performance of the heterojunctions demonstrates the effectiveness of Z-scheme charge transfer pathways in improving HER activity.
Various spectroscopic, microscopic, and structural approaches systematically characterize the materials. The photocatalytic performance of these materials is assessed using electrochemical experiments, photophysical tests, activity and stability evaluation under simulated sun irradiation. Efforts focus on enhancing the photocatalytic performance of metal sulphide and MOF-derived photocatalysts by regulated synthesis parameters, defect adjustments, and heterojunction engineering. This study provides beneficial insights into designs for effective photocatalysts developed for HER applications.
| Date of Award | 17 Mar 2025 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Tao Wu (Supervisor), Mina Liu (Supervisor) & Hao Liu (Supervisor) |