Defect engineering assisted support effect:IrO2/N defective g-C3N4 composite as highly efficient anode catalyst in PEM water electrolysis

Abstract Herein, a strategy is reported for boosting the support effect between IrO2 nanoparticle and g-C3N4 (CN) support via regulating CN with the introduction of N defect, thus improve the intrinsic OER activity of IrO2 in PEM electrolysis. N defective graphite carbon nitride (N-CN) reveals distinctive physicochemical characteristics relative to CN. The mass activity and specific activity of IrO2/N-CN are 7.86 times and 1.75 times relative to IrO2, respectively. Polarization curves exhibit the optimal OER activity of 1.778 V for IrO2/N-CN at 1.6 A cm-2, which is substantially smaller than that of IrO2/CN (1.824 V) and IrO2 (1.846 V). Meantime, IrO2/N-CN maintains good stability during the 300 h stability test at the current density of 1.6 A cm-2. DFT calculations and experimental results reveal that outstanding OER activity and sufficient stability are contributions to the increment of active site accessibility and the moderate adsorption of oxygen intermediates. This work provides a feasible strategy for designing and optimizing highly efficient catalysts in electrocatalytic.