Rational design of nanostructured BiVO₄/FeO_x photoanode coupling with 2D Co(OH)₂ cocatalyst for enhanced photoelectrochemical water splitting

Efficient charge transport and separation is of prime significance to achieve high efficiency of photoelectrochemical (PEC) solar energy conversion. In this study, we designed a novel ternary nanostructured BiVO₄/FeO_x/Co(OH)₂ composite as photoelectrode for enhanced PEC water splitting. Compared with pristine BiVO₄, the fabricated BiVO₄/FeO_x/Co(OH)₂ photoelectrode produced a doubled increase in photocurrent (from 0.36 to 0.72 mA cm⁻² at 1.23 V versus RHE) with a negative shift of 390 mV in the initial potential (from 0.72 to 0.33 V). In addition, the conversion efficiency and photostability for PEC water oxidation were also improved. The elevated PEC properties of ternary composite photoelectrode were originated from the synergy of heterojunction construction and 2D cocatalyst loading that provides effective pathway for promoting charge separation as well as sufficient sites for photoelectrochemical reaction. These findings could provide an exemplary PEC model for enhanced solar hydrogen evolution of BiVO₄ photoanode.