Abstract
A mass production route to single-atom catalysts (SACs) is crucial for their end use application. To date, the direct fabrication of SACs via a simple and economic manufacturing route remains a challenge, with current approaches relying on convoluted processes using expensive components. Here, a straightforward and cost-effective three-dimensional (3D) printing approach is developed to fabricate a library of SACs. Despite changing synthetic parameters, including centre transition metal atom, metal loading, coordination environment and spatial geometry, the products show similar atomic dispersion nature of single metal sites, demonstrating the generality of the approach. The 3D-printed SACs exhibited excellent activity and stability in the nitrate reduction reaction. It is expected that this 3D-printing technique can be used as a method for large-scale commercial production of SACs, thus enabling the use of these materials in a broad spectrum of industrial applications.

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All data supporting the findings of this study are available in the article and its Supplementary information. Source data are provided with this paper.
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Acknowledgements
DFT computations within this work were supported by computational resources provided by the Australian Government through NCI under the National Computational Merit Allocation Scheme and the Phoenix High Performance Compute (HPC) Service at The University of Adelaide. This research was undertaken on the XAS and Soft X-ray beamlines at the Australian Synchrotron, part of ANSTO. F.X. thanks H. Jin, C. Tang, Y. Jiao, Y. Zheng, P. Wang and J. Shan from the school of CEAM, A. Slattery and S. Gilbert from Adelaide Microscopy at the University of Adelaide, and H. Yu from the University of South Australia for constructive suggestions and help. This study was supported by the Australian Research Council (grant Nos. FL170100154-S.Z.Q and DP220102596-S.Z.Q), the New Zealand Health Research Council (grant No. 19/779 to C.X.), the New Zealand Ministry for Business, Innovation and Employment (grant No. MBIE Science Whitinga Fellowship, MWF-UOO2103 to C.X.) and the National Heart Foundation of New Zealand (grant Nos. 1891, 1896 to C.X.).
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F.X. and C.X. conceived the project. S.-Z.Q. supervised the project and whole studies. F.X. and C.X. performed the materials preparations with the assistance of J.T. and T.W. F.X. and D.Y. conducted the electrochemical measurements. X.Z. conducted the DFT calculations. F.X., B.J., T.L. and G.L. performed the physicochemical characterizations. F.X., C.X., X.Z., D.Y. and S.-Z.Q. wrote the manuscript. S.-Z.Q. revised the manuscript for submission.
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Xie, F., Cui, X., Zhi, X. et al. A general approach to 3D-printed single-atom catalysts. Nat. Synth 2, 129–139 (2023). https://doi.org/10.1038/s44160-022-00193-3
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DOI: https://doi.org/10.1038/s44160-022-00193-3
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