Ultrasmall Pt/Nanoceria Hybrids Supported on N-Doped rGO as Electrocatalyst for the Hydrogen Evolution Reaction

Taking advantage of the metal-support interaction is an efficient strategy to rationally design cost-effective and highly efficient catalysts. Herein, we report that tiny Pt species anchored on nanoceria with N-rGO as support (denoted as Pt-CeO₂/N-rGO) display size-dependent activity toward the hydrogen evolution reaction (HER). The Pt_SAPt_NC-CeO₂/N-rGO is far more active than Pt_SA-CeO₂/N-rGO and Pt_SAPt_NP-CeO₂/N-rGO. The overpotential at 10 mA/cm² is only 26 mV for Pt_SAPt_NC-CeO₂/N-rGO (5.0 wt %), ∼16 and 119 mV lower than that of commercial Pt/C (20.0 wt %) and a Pt catalyst supported on N-rGO with similar dispersion form (11.0 wt %), respectively. DFT calculations reveal that the electron interaction between Pt and CeO₂ greatly favor water adsorption and reduce the H₂ evolution energy barrier, which was further optimized by the synergistic effect between Pt_SA and Pt_NC. XPS measurement and charge density difference analysis indicate that electrons transfer from Pt single atoms to CeO₂ and CeO₂ reversely donate electrons to Pt nanoclusters. The electron-rich Pt nanoclusters enhance the electronic conductivity of the catalysts and thus accelerate the H₂ evolution kinetics. Our work provides an idea of how to optimize catalytic performance via manipulating the metal-support interaction.