Water Oxidation by Copper-Amino Acid Catalysts at Low Overpotentials

摘要

Although notable progress has been made in developing first-row transition-metals-based water oxidation catalysts, continuous efforts are required to identify more inexpensive, efficient, and robust catalysts. Here, we demonstrate the utility of a series of readily available complexes formed by earth-abundant copper and amino acids as catalyst precursors. In phosphate solution at pH12, electrolysis with 1mm Cu-II and 4mm Gly results in in situ formation of an amorphous surface precipitate of a CuO/Cu(OH)(2) mixture, which incorporates a substantial amount of phosphate anions. This surface-bound solid can catalyze water oxidation with an impressive onset overpotential of 380mV, an overpotential of 450mV for a current density of 1mAcm(-2), and a low Tafel slope of 64mVdec(-1), which make it among the most active Cu-based heterogeneous electrocatalysts. The copper-based reactivity toward water oxidation is shared by Cu-II complexation to other amino acids as catalyst precursors.