Tuning the Growth Mode of Pt on AuNRs via Modulating the Competition of Pt Deposition and Oxidative Etching of Au Nanorods

Abstract

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