Pt nanodendrites with a PtIr alloy surface structure exhibit excellent stability toward acidic hydrogen evolution reaction

The development of effective and stable electrocatalysts for the hydrogen evolution reaction (HER) in acidic electrolytes is a significant challenge. In this work, homogeneous Pt nanodendrites (Pt NDs) with a PtIr shell were successfully synthesized by a two-step wet chemical method. This open three-dimensional (3D) dendritic structure exhibited exceptional electrocatalytic characteristics, exposing as many active sites as feasible. Furthermore, by alloying Ir with Pt on the surface, catalytic activity was greatly enhanced while ensuring extremely high stability. Iridium surface-enriched platinum nanodendritic catalysts (Pt@PtIr NDs) outperformed the control samples and the commercial catalysts. In acidic HER test, Pt@PtIr NDs had a lower overpotential (22 mV) than Pt NDs (26 mV) and commercial Pt/C (31 mV) at 10 mA/cm², and the activity of Pt@PtIr NDs remained consistent even after undergoing a continuous durability test for at least 168 h, which was much superior to the performance of commercial Pt/C (10 h) under identical test conditions. This study revealed that the application of 3D Pt dendritic metal alloys may offer a chance for the development of enhanced electrocatalysts in acidic HER.