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Regulation of Pd single-atom coordination for enhanced photocatalytic oxidation of toluene to benzaldehyde

Nature Synthesis volume 4, pages 965–975 (2025)Cite this article

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Abstract

Photocatalytic oxidation represents an effective means of hydrocarbon valorization, but achieving high-selectivity intermediate products at high substrate conversion remains challenging. Here single-atom Pd–O catalytic sites with different coordination environments are synthesized. The Pd–O3 coordinated single sites show the best catalytic performance for selective toluene oxidation, exhibiting a high benzaldehyde selectivity of 95% at 95% toluene conversion, and a benzaldehyde yield rate up to 12,000 μmol g−1 h−1, surpassing previously reported results. The Pd–O3 catalytic sites serve as the location of photogenerated charge separation and C(sp3)–H bond activation. These sites can trap the photogenerated holes effectively to enhance the charge-separation efficiency, improving the yield rate by a factor of 2.9 relative to the Bi2WO6 support. Additionally, the coordination structure weakens benzaldehyde adsorption, reducing overoxidation and improving reaction selectivity. This work highlights the importance of single-atom site coordination in optimizing the activity and selectivity of photocatalytic oxidation reactions.

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Fig. 1: Preparation and structural characterization of Pd/BWO catalysts.
Fig. 2: Evaluation of photocatalytic selective oxidation of toluene.
Fig. 3: Investigation of active species, reaction dynamics and carrier dynamics.
Fig. 4: Surface reaction mechanism and DFT calculations.
Fig. 5: Schematic representation of the photocatalytic selective oxidation of toluene using single-atom Pd/BWO photocatalysts with different palladium coordination environments.

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The data supporting the findings of this study are available within the article and its Supplementary Information. Source data are provided with this paper.

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Acknowledgements

This work was supported by the National Natural Science Foundation of China (grant number 22275109) and the Fundamental Research Center of Single-Atom Catalysis (grant number 22388102). X.C. thanks the China Postdoctoral Science Foundation (2022M722834, 2023T160587). We greatly appreciate L. Sun for his support on this work. The DRIFTS measurements were performed at the Research Center for Eco-Environmental Sciences with the help of C. Chen. C. He, Y. Zeng and L. Chen offered valuable suggestions about the measurements. We thank the SPring-8 (Japan) 12B2 Taiwan beamline of the National Synchrotron Radiation Research Center (NSRRC) and the BL11B station at the Shanghai Synchrotron Radiation Facility for XAFS measurement. We acknowledge the support of the Analysis Center of Tsinghua University and S. Du from the Dalian Institute of Chemical Physics for XPS experiments.

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  1. These authors contributed equally: Ruiyi Sun, Xing Cao, Junguo Ma.

Authors and Affiliations

  1. Engineering Research Center of Advanced Rare Earth Materials, Department of Chemistry, Tsinghua University, Beijing, China

    Ruiyi Sun, Chen Chen, Qing Peng & Yadong Li

  2. Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, China

    Xing Cao

  3. Anhui University, Hefei, China

    Junguo Ma

  4. Center for Reliability Sciences and Technologies; Center for Sustainability and Energy Technologies, Chang Gung University, Taoyuan, Taiwan

    Hsiao-Chien Chen

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Contributions

R.S., X.C. and J.M. performed the experimental work and analysed the results. H.-C.C. helped with the XAFS experiments. C.C. provided fruitful advice on the work. R.S., X.C., J.M., Q.P. and Y.L. conceived and designed the experiments. All authors contributed to the overall scientific discussions and co-wrote the paper.

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Correspondence to Xing Cao, Qing Peng or Yadong Li.

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Nature Synthesis thanks Liyong Gan, Shuang-Feng Yin and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Alexandra Groves, in collaboration with the Nature Synthesis team.

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Sun, R., Cao, X., Ma, J. et al. Regulation of Pd single-atom coordination for enhanced photocatalytic oxidation of toluene to benzaldehyde. Nat. Synth 4, 965–975 (2025). https://doi.org/10.1038/s44160-025-00782-y

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