Regulating the protecting ligand content on Pt cluster surface for highly efficient electrocatalytic hydrogen evolution reaction

Abstract

Pt-based nanomaterials are considered to be the optimal electrocatalysts for hydrogen evolution reaction (HER), while its high cost and limited natural abundance pose significant barriers to large-scale application. Pt nanoclusters (Pt NCs) with high specific surface area and high atom utilization have promising catalysis application for efficient HER. Nonetheless, the pursuit of highly active and stable Pt NCs remains a challenge, as surface ligands may impede their functionality, whereas absence of surface ligand protection can result in instability. Herein, a series of Pt₆ NCs with varying quantities of ligands were fabricated by annealing under 300 °C for different times. The results show that the removal of appropriate amount of ligands can enhance the catalytic activity and meanwhile preserve stability of Pt₆ NCs. Notably, the optimized sample with annealing treatment for 2 h (Pt₆/CNT-2) displayed a superior HER performance with an overpotential of only 24.6 mV at 10 mA·cm⁻² and high stability, comparable to that of commercial Pt/C. Furthermore, the mass activity of Pt₆/CNT-2 at −0.05 V is 19-fold greater than that of commercial Pt/C, significantly reducing the consumption of precious metals. This work provides a novel idea for designing ultrasmall noble-metal NCs electrocatalysts with excellent activity and stability.