Dark-Field Imaging of Cation Exchange Synthesis of Cu_{2- x}S@Au₂S@Au Nanoplates toward the Plasmonic Enhanced Hydrogen Evolution Reaction

The development of novel electrocatalysts, especially Pt-free electrocatalysts, is of great significance for evolving hydrogen fuel cells. Two-dimensional materials have many advantages, such as large specific surface area, abundant active edges, and adjustable electronic structure, which provide broad prospects for studying high-performance electrocatalysts. In this paper, Cu_2-xS@Au₂S@Au nanoplates (NPs) were synthesized by cation exchange, which showed good catalytic performance toward the hydrogen evolution reaction (HER). Dark-field microscopy can help observe the process of cation exchange in real time to precisely control the synthesis of the composite materials. The synthesized Cu_2-xS@Au₂S@Au nanoplates (NPs) exhibited greatly enhanced plasmonic emission, resulting in accelerated chemical conversion and improved HER efficiency. Under 532 nm laser excitation, the overpotential of the HER shifted from 152 to 96 mV at a current density of -10 mA cm^-2. The plasmonic nanocatalysts show exciting prospects in the field of new energy resources.