H 2 , as a renewable source of energy, is regarded as an ideal alternative to traditional fossil fuels due to its excellent density of energy, sustainability, and ecological friendliness. Solar-driven semiconductor photocatalytic technology is a potential approach for H 2 evolution. Importantly, it is significant to explore the efficient photocatalysts to strengthen photocatalytic H 2 evolution. TiO 2 has been extensively studied as a water-splitting photoanode for its excellent chemical durability, relatively inexpensive cost, and harmlessness. However, the inadequate light-harvesting ability, quick photogenerated carrier recombination, and inferior redox capacity of TiO 2 restrict the photocatalytic activity. To address these problems, designing and constructing a defect‐engineered TiO 2 -based S-scheme heterojunction is of considerable significance for achieving high-efficiency photocatalytic activity. Zn 0.5 Cd 0.5 S, a ternary metal sulfide with excellent visible light absorption and stability, matches TiO 2 well for S-scheme heterojunction construction. Yet, the synergistic integration of defect engineering with the S-scheme heterojunction in TiO 2 /Zn 0.5 Cd 0.5 S remains unexplored. Therefore, constructing a defect-engineered TiO 2 /Zn 0.5 Cd 0.5 S S-scheme heterojunction would be valuable for advancing the progress of photocatalysis.
Recently, a research team led by Dr. Bin Sun and Prof. Guowei Zhou from Qilu University of Technology (Shandong Academy of Sciences), China presents a defect-engineered TiO 2 /Zn 0.5 Cd 0.5 S S-Scheme heterojunction for photocatalytic H 2 evolution. An oxygen vacancy-rich TiO 2 -Ov/Zn 0.5 Cd 0.5 S S-scheme heterojunction photocatalyst with dual charge transfer pathways achieves high-efficiency photocatalytic H 2 evolution activity. Meanwhile, the S-scheme charge transfer pathway, dynamic behavior, and surface reaction active sites are systematically analyzed. The results were published in Chinese Journal of Catalysis (DOI: 10.1016/S1872-2067(25)64909-6).
The defect-engineered S-scheme heterojunction is designed and constructed through a hydrothermal method, achieved by in situ growth of Zn 0.5 Cd 0.5 S nanoparticles onto oxygen vacant TiO 2 flower-like microspheres to establish TiO 2 -Ov/Zn 0.5 Cd 0.5 S heterojunction. Remarkably, the optimal heterojunction achieves a superior H 2 evolution rate of 15.31 mmol g –1 h –1 , surpassing those of TiO 2 , TiO 2 -Ov, Zn 0.5 Cd 0.5 S, and defect-free TiO 2 /Zn 0.5 Cd 0.5 S. Meanwhile, TiO 2 -Ov/Zn 0.5 Cd 0.5 S S-scheme heterojunction also exhibits excellent cycling stability. Furthermore, the H adsorption free energy of S site approaching zero indicates an optimal adsorption-desorption equilibrium for H 2 evolution.
Within the photocatalytic system, the synergistic effects of oxygen vacancy and S-scheme heterojunction endow excellent light absorption ability, effective spatial separation and transfer of photo-induced charge, and superior redox capacity. In particular, the presence of dual photo-induced charge transfer pathways significantly enhances the trapping efficiency of photo-induced electrons in TiO 2 -Ov and effectively promotes the combination of photo-induced electrons in TiO 2 -Ov with holes in Zn 0.5 Cd 0.5 S. Furthermore, the in-situ characterization and DFT calculation further verify the S-scheme charge transfer mechanism in TiO 2 -Ov/Zn 0.5 Cd 0.5 S heterojunction. This work provides a feasible strategy for constructing high-performance S-scheme heterojunction photocatalyst with defect engineering for solar to H 2 energy conversion. The results were published in Chinese Journal of Catalysis (DOI:10.1016/S1872-2067(25)64909-6)
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Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top six journals in Applied Chemistry with a current SCI impact factor of 17.7.
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Chinese Journal of Catalysis
Defect-engineered S-scheme charge transfer in TiO2/Zn0.5Cd0.5S heterojunction for high-efficiency photocatalytic hydrogen evolution
5-May-2026