Co-First Authors: Rongjie Li and Heng Li
Corresponding Authors: Gang Liu, Xiaoying Qi, Lirong Zheng, and Xuebo Chen
DOI: 10.1002/adfm.74535
Research Highlights
This study reveals the synergistic mechanism between Ru single atoms and second-nearest-neighbor Cd vacancies in the Ru-Cd1-xS/Ti3C2Tx photocatalyst. This mechanism enhances photocatalytic hydrogen evolution through two complementary pathways: (i) it optimizes the adsorption of H and H2 on S sites adjacent to the Ru single atoms; and (ii) the resulting interfacial Ru–O atomic bridge substantially strengthens the heterojunction electric field and accelerates interfacial charge transfer. As a result, the catalyst achieves a high photocatalytic hydrogen-evolution rate of 48.58 mmol g-1 h-1.
Introduction
In February 2026, Advanced Functional Materials published online the latest research from Professor Xuebo Chen's team at Beijing Normal University in the field of photocatalytic hydrogen evolution. The study reports a surface/interface synergistic strategy involving Ru single atoms and second-shell cation vacancies for enhanced photocatalytic hydrogen evolution. Rongjie Li and Heng Li are the co-first authors. The co-corresponding authors are Researcher Gang Liu and Senior Engineer Xiaoying Qi of the National Center for Nanoscience and Technology, Associate Researcher Lirong Zheng of the Institute of High Energy Physics, Chinese Academy of Sciences, and Professor Xuebo Chen of Beijing Normal University.
Background
Solar-driven photocatalytic hydrogen evolution is an important route toward sustainable energy conversion. Single-atom catalysts have emerged as an effective strategy for reducing the loading of precious-metal cocatalysts because they offer nearly 100% atomic utilization and tunable electronic structures. Introducing defects, such as vacancies, near isolated metal atoms can further regulate their electronic structures and catalytic activity. Two-dimensional MXene materials show considerable potential as cocatalysts because of their excellent metallic conductivity and tunable surface functional groups. This study systematically investigates the role of defect-coordinated single-atom structures located at surfaces and interfaces in photocatalytic hydrogen-evolution systems, providing guidance for the rational design of highly efficient photocatalysts.
Equipment Used in the Study
Figure Analysis
First-principles DFT calculations, including analyses of the Gibbs free energy of surface hydrogen adsorption and the electronic density of states, reveal how Ru single atoms and Cd vacancies synergistically regulate the surface electronic structure.
Figure 1. DFT Calculations—Surface.
First-principles DFT calculations based on work functions, differential charge-density analysis, and Bader charge analysis demonstrate that Ru single atoms and Cd vacancies synergistically strengthen the interfacial Schottky electric field.
Figure 2. DFT Calculations—Interface.
The Ru-Cd1-xS/Ti3C2Tx photocatalyst was controllably synthesized through a two-step process, with Ru single atoms atomically dispersed on the CdS surface.
Figure 3. Synthesis Schematic and Microscopic Characterization.
Characterization of the crystal structure, chemical structure, and electronic structure of the Ru-Cd1-xS/Ti3C2Tx photocatalyst.
Figure 4. Structural Characterization.
Under visible-light irradiation, the optimized Ru0.1-Cd1-xS/Ti3C2Tx-1.5 catalyst achieves a photocatalytic hydrogen-evolution rate of 48.58 mmol g-1 h-1, which is 45.4 times that of pristine CdS.
Figure 5. Photocatalytic Hydrogen-Evolution Performance, Band Structure, In Situ Irradiation EPR, and XPS Characterization.
The rapid electron-transfer pathway driven by interfacial Ru–O bonds significantly improves the separation efficiency of photogenerated charge carriers.
Figure 6. Femtosecond Transient Absorption Spectra.
A synergistic photocatalytic hydrogen-evolution mechanism involving Ru single atoms and second-shell Cd vacancies at the surface and interface is proposed.
Figure 7. Photocatalytic Mechanism of Ru-Cd1-xS/Ti3C2Tx for Visible-Light-Driven Hydrogen Evolution.
Conclusion
This study clarifies a “1 + 1 + 1 > 3” synergistic enhancement mechanism arising from the interaction among surface metal single atoms, well-defined cation vacancies, and interfacial covalent bonds. The findings provide valuable insights into the rational design of advanced photocatalytic and catalytic systems for energy conversion and chemical transformation.
Reference
R. Li, H. Li, H. Li, et al. Orchestrating Single Ru Atoms and Second-Shell Cation Vacancies in CdS Interfaced With Ti3C2Tx MXene for Boosting Photocatalytic Hydrogen Evolution.
Advanced Functional Materials (2026): e74535.
https://doi.org/10.1002/adfm.74535
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