Modifying charge transfer between rhodium and ceria for boosted hydrogen oxidation reaction in alkaline electrolyte.

Sluggish kinetics of hydrogen oxidation reaction (HOR) in alkaline solution has restricted the rapid development of hydrogen economy. Constructing catalyst with metal-oxide heterostructures can enhance HOR performance; however, little studies concentrate on charge transfer between them, and the corresponding effects on reactions remain unclear. Herein, we report charge-transfer-adjustable CeO/Rh interfaces uniformly dispersed on multiwalled carbon nanotube (CNT), which exhibit excellent alkaline HOR performance. Results confirm that the charge transfer from Rh to CeO could be conveniently tuned via thermal treatment. Consequently, the adsorption free energies of H* in Rh sites and OH* adsorption strength in CeO could be adjusted, as corroborated by density functional theory study. The optimized CeO/Rh interfaces exhibit an exchange current density and a mass-specific kinetic current of 0.53 mA cm and 830 A g at an overpotential of 50 mV, respectively, which surpasses most of the advanced noble-metal-based electrocatalysts. This work provides a new insight of harnessing charge transfer of heterostructure to enhance catalytic activities.