Surface confinement of sub-1 nm Pt nanoclusters on 1D/2D NiO nanotubes/nanosheets as an effective electrocatalyst for urea-assisted energy-saving hydrogen production

To address the high cost and limited electrochemical endurance of Pt-based electrocatalysts, the appropriate introduction of transition metal-based compounds as supports to disperse and anchor Pt species offers a promising approach for improving catalytic efficiency. In this study, sub-1 nm Pt nanoclusters were uniformly confined on NiO supports with a hierarchical nanotube/nanosheet structure (Pt/NiO/NF) through a combination of spatial domain confinement and annealing. The resulting catalyst exhibited excellent electrocatalytic activity and stability for hydrogen evolution (HER) and urea oxidation reactions (UOR) under alkaline conditions. Structural characterization and density functional theory calculations demonstrated that sub-1 nm Pt nanoclusters were immobilized on the NiO supports by Pt–O–Ni bonds at the interface. The strong metal-support interaction induced massive charge redistribution around the heterointerface, leading to the formation of multiple active sites. The Pt/NiO/NF catalyst only required an overpotential of 12 and 136 mV to actuate current densities of 10 and 100 mA cm⁻² for the HER, respectively, and maintained a voltage retention of 96% for 260 h of continuous operation at a current density of 500 mA cm⁻². Notably, in energy-efficient hydrogen production systems coupled with the HER and UOR, the catalyst required cell voltages of 1.37 and 1.53 V to drive current densities of 10 and 50 mA cm⁻², respectively—approximately 300 mV lower than conventional water electrolysis systems. This study presents a novel pathway for designing highly efficient and robust sub-nanometer metal cluster catalysts.