High Formate Selectivity and Deactivation Mechanism of CuS Nanoparticles in CO<sub>2</sub> Electrocatalytic Reduction Reaction
Min Wang, Xiaoyao Li, Xia Ma, Jie Wang, Xixiong Jin, Lingxia Zhang, Jianlin Shi
Abstract
Abstract CO 2 electroreduction into liquid fuels is of broad interest and benefits reducing the energy crisis and environment burdens. CuS has been reported to be a desirable candidate for CO 2 electroreduction into formate; however, its formate selectivity and stability are still far from the demands of practical application. Herein, we report CuS nanoparticles exhibiting good Faradaic efficiency of formate (about 98 %) in CO 2 electroreduction and its deactivation mechanism during the reaction. The deactivation of CuS was found to be associated with the reconstruction and S loss of CuS, which deteriorates the Faradaic efficiency of formate. Combined with ionic and gas analyses, the S atom in CuS was lost in the form of H 2 S, SO 2 , and SO 4 2− , followed by the reconstruction of CuS into copper oxides. Such a catalyst reconstruction facilitates electroreductions of CO 2 and H 2 O, respectively, into CO and H 2 , etc., resulting in the degradation of catalytical performance of CO 2 electroreduction into formate. This work reveals the important role of S loss and reconstruction of metal sulfide catalysts during the electroreduction reaction, which may benefit the further development of CuS‐based electro‐catalyst for CO 2 electroreduction.