Electrodeposited Co-Substituted LaFeO3 for Enhancing the Photoelectrochemical Activity of BiVO4

Co-substituted LaFeO₃ was electrodeposited on the surface of BiVO₄ as a co-catalyst to enhance the water splitting performance. Compared to bare BiVO₄, the BiVO₄/Co-LaFeO₃ composite photoanode shows a water oxidation photocurrent of 3.4 mA/cm² at 1.23 V versus reverse hydrogen electrode, accompanied by a notable cathodic shift in the onset potential for 300 mV. Combined optical and electrochemical characterizations show that the solid/electrolyte charge transfer efficiency of BiVO₄ are dramatically improved by the incorporation of Co-substituted LaFeO₃. From the surface kinetic study of charge carriers by intensity-modulated photocurrent spectroscopy, a suppressed surface recombination rate constant is observed and the enhanced photoelectrochemical water splitting performance observed in the BiVO₄/Co-LaFeO₃ photoanode is attributed to the surface passivation effect of Co-substituted LaFeO₃.