Liquid Metal Alloys Enable Efficient Formate Electrosynthesis

Abstract

Liquid metals are an interesting class of materials with the unique combination of metallic nature and liquid fluidity, and have recently been explored in many emerging fields. Their potential applications in catalysis, unfortunately, remain largely untapped. Herein, Ga‐mediated liquid metal alloying as an effective strategy is demonstrated to prepare functional alloys for catalysis. The alloying is carried out by dissolving indium or tin pellets in liquid gallium at room temperature or assisted by gentle heating, giving rise to binary Ga1−xInx and Ga1−xSnx liquid metal alloys with tunable chemical compositions. When further subjected to ultrasonication in water, they are ruptured into nanosized particles with liquid metal cores and thin surface oxide shells. Electrochemical measurements reveal that the liquid metal alloying significantly promotes electrocatalytic CO2 reduction to formate. Taking Ga0.75In0.25 as an example, its formate Faradaic efficiency is enhanced by 10%–20% compared to those of Ga and In, and its formate partial current density is 4–6 times larger than those of Ga and In. This enhancement is rationalized via computational simulations showing that the surrounding of In active sites with Ga atoms deactivates the undesirable reaction pathways to CO or H2, and facilitates selective formate electrosynthesis.