Electrochemical measurements were performed by Bio-Logic SP-200 Potentiostat (BioLogic Science Instruments, France) in a gas diffusion electrode (GDE) -based reaction cell with a threeelectrode framework. Carbon rod and Ag/AgCl were utilized as the counter electrode and reference electrode, respectively. All potentials measured in this work were converted to RHE by the following equation: E (vs RHE) = E (vs Ag/AgCl) + 0.197 + (0.0591 ⅹ pH)