摘要
Synthesis of well-controlled faceted metal nanocrystals is important for many applications. It has received much attention in advancing product selectivity of copper-catalyzed CO2 electrolysis. We developed a facile electrodeposition method that can synthesize shape-controlled copper nanocrystals with ultra-clean surfaces that are difficult to obtain otherwise. Shape control is achieved via the controlled adsorption of CO2 on copper surfaces by different alkali cations during electrodeposition, with ultra-clean surfaces subsequently obtained upon releasing the electric field. In situ infrared spectroscopy reveals the strong adsorption of CO2 on copper surfaces in the presence of heavy alkali cations during electrodeposition, yielding well-defined nanocubes. The preferential adsorption of CO2 on the Cu(100) surface in the presence of cesium cations is explained using constant-potential density functional theory calculations. The electrodeposited ultra-clean copper nanocubes are readily usable in actual electrolyzers and deliver a remarkable faradaic efficiency of over 80% for C2+ products at -300 mA cm-2.