Copper Nanoparticles Dotted on Copper Sulfide Nanosheets for Selective Electrocatalytic Oxidation of Glycerol to Formate

This work provides a simple method for the development of a high-activity non-noble metal catalyst for the oxidation of glycerol (GLY) to formate. CuS nanosheet arrays are grown in situ on the brass mesh by low-temperature sulfuration, and then copper nanoparticles are uniformly dotted on CuS nanosheets through disproportionation reaction. As-fabricated Cu-CuS/BM is used for glycerol oxidation reaction (GOR), and the current density can reach 10 mA·cm^–2 when the potential is 1.37 V vs RHE. A high selectivity of 86.0% and a Faradaic efficiency of 90.4% for formate production are achieved, and the average selectivity of 20 consecutive cycles of electrolysis is 82.6%, confirming the excellent activity and stability of Cu-CuS/BM. The formation of formate as the main oxidation product that conforms to the primary alcohol oxidation path is proved through high-performance liquid chromatography and in situ Fourier transform infrared spectroscopy. The mechanism of GOR induced by Cu-CuS/BM is proposed through density functional theory calculation and X-ray photoelectron spectroscopy analysis, in which the combination of copper nanoparticles and CuS significantly enhances the adsorption for GLY, and Cu­(II) produced during the GOR facilitates the adsorption for OH^– to form Cu­(II)-OH_ads on the catalyst surface, which is beneficial to the oxidation of absorbed GLY.