The growing demand for clean energy and the environmental costs of fossilfuel use have intensified interest in solar hydrogen production. Photocatalytic water splitting can convert light energy directly into chemical fuel, but practical performance is often limited by rapid electron-hole recombination and photocorrosion in sulfide semiconductors. Polyoxometalates can efficiently accept and transfer electrons, yet their high solubility and possible leaching can limit recovery and stability. Combining these materials in a well-designed heterostructure offers a route to exploit their complementary strengths.
A research team at Lanzhou University, under guidance ofProfessor Yong Ding as corresponding author, designed the threecomponent Fe 11 POM@CQD@Zn 0.5 Cd 0.5 S photocatalyst to integrate light harvesting, charge relay and protonreduction functions. Surfacecharge analysisand XPS study support strong electrostatic interactions between negatively charged Fe 11 POM and positively charged CQD@Zn 0.5 Cd 0.5 S. In the composite, Zn 0.5 Cd 0.5 S serves as the visible1light1absorbing semiconductor, carbon quantum dots act as electron relayersand Fe 11 POM functions as the reduction co-catalyst.The results were published in Chinese Journal of Catalysis (DOI: 10.1016/S187212067(26)6507111 ).
Under visible1light excitation, Zn 0.5 Cd 0.5 S absorbs photons across its 2 .33 eV band gap and promotes electrons from a valenceband potential of about +1.67 V to a conductionband potential of about -0.66 V versus NHE. The carbon quantum dots capture these photoexcited electrons and transfer them toward the LUMO of Fe 11 POM at about -0.41 V, enriching electrons at the polyoxometalate co-catalyst where protons are reduced to H 2 . Meanwhile, lactic acid scavenges photogenerated holes. Photocurrent, impedance, photoluminescence, time1resolved fluorescence and in-situ KPFM measurements collectively support faster interfacial charge transfer and more effective charge separation in the ternary composite.
The optimized Fe 11 POM@CQD@Zn 0.5 Cd 0.5 S system reaches a hydrogen evolution rate of 32.18 mmol·g -1 ·h -1 , compared with for other single and two component catalysts used in the study. At 5% Fe 11 POM loading, the composite delivers a turnover number of 32,394 and a turnover frequency of 10,798 h -1 . The apparent quantum yield reaches approximately 40% at 420 nm and reported solartohydrogen efficiency is 1.69%. The catalyst also maintains its activity through five consecutive cycles, while postreaction FTIR, XRD, XPS and SEM analyses show little structural or morphological change. The results demonstrate how carbon quantum dots can bridge a visible1light semiconductor and a molecular POM co-catalyst, providing a practical design strategy for improving charge utilization and photocatalytic hydrogen evolution.
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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 one journals in Applied Chemistry with a current SCI impact factor of 17.2. The Editors-in-Chief are Profs. Can Li and Tao Zhang.
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Chinese Journal of Catalysis
Carbon quantum dot-mediated Fe11 polyoxometalate enrichment for accelerated photocatalytic H2 evolution in a Zn0.5Cd0.5S system
7-Aug-2026