Hollow CuS Microcube Electrocatalysts for CO2 Reduction Reaction

Electrocatalytic carbon dioxide reduction reaction (CO2RR) is a promising strategy to mitigate or to address the issues caused by increasing CO2 emissions, but the implementation of such a technique highly depends on the exploration of highly efficient electrocatalysts toward the CO2RR. Here, we report a reliable route for the synthesis of hollow CuS microcubes (h-CuS MCs) through a galvanic replacement reaction of the Cu2O microcube (Cu2O MC) precursor. A variety of characteristic techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy, were performed to study the morphology, crystalline structure, and surface properties. Systematic electrochemical studies demonstrate that the electrocatalytic activity for CO2RR is sensitive to crystalline structure, morphology, and size of Cu-based materials. The h-CuS MCs manifest the highest electrocatalytic activity upon electrocatalyzing CO2RR among the set of Cu-based materials tested, as evidenced by a rather low overpotential and an enhanced faradaic efficiency for CO production.