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)-OHads on the catalyst surface, which is beneficial to the oxidation of absorbed GLY.