Supported catalysts with the active metal components from isolated atoms to nanoparticles display the catalytic performances readily tuned by the interfacial effects, which arise from the electron transfer and mass transport in the interfaces. Particularly, the electron transfer driven by the different band structures of the constituents, and the migration of the cations and anions of the supports correspond to the electronic and chemical parts of the metal-support interactions (MSI). Reaction-generated adsorbates also participate in the interfacial events, such as H-spillover from the metal deposits to the support surfaces. For the hydrogenation reactions catalyzed by the supported assemblies, multiple interfacial effects may occur simultaneously, which all closely relate to the catalytic performances. Their individual roles have been clarified thoroughly, the joint influences and their correlations, however, remain to be a challenging but significant subject, especially for the well-designed metal deposits ranging from single atoms to nanoparticles. In our work, we selected atmospheric CO2 hydrogenation as the probe reaction and discovered the competitive relationship of MSI and H-spillover effect in tuning the activities of CeO2 supported Ru single atoms, nanoclusters and nanoparticles. The two effects reached a balance for the nanoclusters with the optimized activity. Further deposited with Rh, Pd, Ir and Pt components, the supported assemblies exhibited CH4 selectivities varying in the order similar to the sequence of d-orbital energies of the metal atoms, which were attributed to the different intensities of electronic MSI and interfacial bonding with the formyl intermediate. The results uncover that different interfacial effects are likely to exert correlative influences on the catalytic performances, and call for the comprehensive design of the supported assemblies to acquire the synergistic interfacial effects and thus the optimized activities.

Interfacial effects in CO2 hydrogenation of CeO2 supported metal single atoms, nanoclusters and nanoparticles

2019 Spring National Meeting

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