Superior overall water splitting performance in polypyrrole photoelectrode by couplingNrGOand modifying electropolymerization substrate

Abstract

AbstractWe prepare photoelectrodes with mixed metal oxides (TiO2‐RuO2), polypyrrole (PPy) and N‐doped reduced graphene oxide (NrGO) on titanium (Ti) substrate for overall water splitting and methylene blue degradation during two steps; including a sol–gel deposition of mixed metal oxide (MMO) and electrodeposition of PPy or PPy‐NrGO films. The as‐prepared photoelectrodes are characterized by physical and photoelectrochemical measurements. Ti/MMO/PPy‐NrGO photoelectrode exhibit a considerably photocurrent density of −6.97 mA cm−2(at 0 V vs. reversible hydrogen electrode [RHE]) and 12.89 mA cm−2(at 1.23 V vs. RHE) for hydrogen and oxygen generations, respectively. However, promotion in the H+/H2efficiency (40.25%) is about 28 orders of magnitude while in the case of H2O/O2(13.77%) is 10 times. The electrochemical impedance spectroscopy and Mott–Schottky measurements reveal that the simultaneous incorporation of MMO and NrGO nanosheets in PPy coating leads to the lowest charge transfer resistance at the photoelectrode/electrolyte interface and an improvement in charge carrier density.