Fine-Tuning the Coordination Structure and Identifying Pt 1 –O v –Ce as the Active Site for Selective Hydrogenations over Pt 1 /CeO 2 Single-Atom Catalysts

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Abstract
Single-atom catalysts (SACs) have shown exceptional promise in a variety of selective hydrogenations due to their uniform and isolated active sites, yet the intrinsic nature of the active sites and reaction mechanism remain elusive. Herein, by a rapid thermal treatment (RTT) method, we are able to finely tune the coordination structure of Pt1/CeO2 SAC and establish a linear correlation between the Pt–O coordination number, electronic structure, and catalytic activity for furfural/3-nitrostyrene hydrogenations. Integrated quasi in situ spectroscopic characterizations and DFT calculations reveal the structural evolution of Pt1–Ov–Ce active sites and the redox mechanism. RTT at 600 °C results in the formation of Pt1–Ov–Ce, which allows for the preferential end-on adsorption of ─C═O/–NO2 groups into Ov and the charge transfer from the Pt1 single atom to the reactant. On the other hand, hydrogen is dissociated on the Pt single atoms and then reacts with the adsorbed ─C═O/–NO2 group to accomplish the selective hydrogenation, accompanied by the regeneration of Ov. Moreover, the interfacial Pt1–Ov–Ce is found to be 2.4–15.7-fold more active than Pt1–––Ov (peripheral Ov). These findings highlight the dictating role of the coordination structure of SACs and elucidate the cooperative mechanism between Pt single atoms and interfacial oxygen vacancies, thus offering design principles for overcoming the activity-selectivity trade-off in other selective hydrogenations.
Funding Information
  • National Key Research and Development Program of China (2023YFA1506603)
  • Youth Innovation Promotion Association of the Chinese Academy of Sciences (2022185)
  • Postdoctoral Fellowship Program (Grade B) of China Postdoc-toral Science Foundation (GZB20250270)
  • CAS Project for Young Scientists in Basic Research (YSBR-022)
  • National Natural Science Foundation of China (22132006)
  • National Natural Science Foundation of China (22172159)
  • National Natural Science Foundation of China (22472131)
  • NSFC Center for Single-Atom Catalysis (22388102)

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