Tuning the growth mode of Pt on AuNRs by modulating the competition between Pt deposition and oxidative etching on Au nanorods

Abstract

In this work, through the systematic modulation of the concentration of the cetyltrimethylammonium bromide (CTAB) surfactant in a growth solution, the competitive deposition of Pt on Au nanorods (AuNRs) and Br⁻ ion-induced oxidative etching of AuNRs were achieved under high-temperature conditions. As a result, two representative AuNR–Pt heterostructures were successfully obtained, namely, G- and E-Au–Pt structures, which featured the growth of dense Pt spikes on the surface of AuNRs and a thin Pt shell on etched AuNRs, respectively. The E-Au–Pt structure showed an ultra-low overpotential of 9.8 mV at 10 mA cm⁻² for the alkaline hydrogen evolution reaction (HER), which was superior to those of the G-Au–Pt structure and commercial Pt/C. The water activation capability arising from the abundant active sites on E-Au–Pt endowed it with enhanced alkaline catalytic activity. The oxidative etching of AuNRs assisted by Br⁻ played a crucial role in the formation highly active sites on the E-Au–Pt structure. This unique strategy provides new insights and an important reference for the rational design and controlled synthesis of advanced electrocatalysts and thus proves to be helpful in expanding their practical applications in various fields.