Efficient Photoelectrocatalytic Water Oxidation by Palladium Doped g-C3N4 Electrodeposited Thin Film

Novel photoanodes for photoelectrocatalytic water oxidation were designed based on the electrodeposited thin film of palladium and silver-doped graphitic carbon nitride. For the first time, the photoelectrocatalytic oxygen evolution of Pd@g-C3N4 photoanode was investigated in this research. To elucidate the role of Pd and compare it with Ag, the photocurrent density, photostability, intrinsic electronic properties, and interfacial reaction kinetics at electrode/electrolyte interface were measured. The photoconversion efficiencies of 0.162% at 0.44 V (vs RHE) for Pd2%@g-C3N4 and 0.076% at 0.38 V (vs RHE) for Ag2%@g-C3N4 were achieved under visible light irradiation and are greater than that of g-C3N4 (0.014% at 0.62 V vs RHE). The transient photocurrent density for g-C3N4, Ag2%@g-C3N4, and Pd2%@g-C3N4 photoanodes was achieved as 24.5, 40.6, and 79.2 μA cm–2, respectively. The Mott–Schottky plots showed that the degree of band bending for Pd@g-C3N4 is deeper than those of g-C3N4 and Ag@g-C3N4 which leads to the facilitated electron transfer at the photelectrode/electrolyte interface.