Green electrodeposition synthesis of NiFe-LDH/MoOx/BiVO4 for efficient photoelectrochemical water splitting

Herein, a facile green synthetic protocol for nanoporous NiFe-LDH/MoOx/BiVO4 had been established via an electrochemical deposition method for enhanced photoelectrochemical cell (PEC) performance. The rational design of nanoporous NiFe-LDH/MoOx/BiVO4 played a vital role in improving the photocurrent density and achieving 2.7 mA /cm2 at 1.23 VRHE (3.9 - fold higher than BiVO4) with a negative onset potential of 267 mV offset. Moreover, the holes were efficiently consumed for water splitting through the cyclic reaction of NiFe-LDH layer. Thus, the nanoporous NiFe-LDH/MoOx/BiVO4 photoanode dramatically improved bulk charge transfer efficiency and surface charge injection efficiency reaching nearly 50% and 95% at 1.23 VRHE, respectively. In addition, the accumulated charge test proved that Mo oxide had the function of transferring holes. And the highest photovoltage and lowest charge recombination kinetics of composite photoanode also presented that the oxide species of Mo and NiFe-LDH had the properties of a passivation layer which were characterized by OCP (Open Circuit Potential) and IMPS (Intensity Modulated Photocurrent Spectroscopy) test. The excellent photocurrent density and facile layer-by-layer synthesis of NiFe-LDH/MoOx/BiVO4 nanocomposite made it a promising photocatalytic material for practical applications. This newly designed strategy was anticipated to be applied in future promising photoanodes for PEC water splitting.