rGO decorated semiconductor heterojunction of BiVO4/NiO to enhance PEC water splitting efficiency.

Monoclinic phase of BiVO 4 is a promising photoanode material for photoelectrochemical (PEC) water splitting, but its sluggish water oxidation kinetics and frequent bulk charge recombination greatly reduce its efficiency of PEC water splitting. A novel BiVO 4 /NiO/rGO photoanode was very simply prepared by electrodeposition, solution immersion and spin coating methods, in particular, the solution immersion method to loading NiO has never been reported in PEC research. Compared with BiVO 4 , the photocurrent density of the ternary photoanode reaches 1.52 mA / cm2 at 1.23 V vs RHE, which is 2.41 and 1.39 times higher than that of pure BiVO 4 and binary BiVO 4 /NiO photoanode, respectively. The onset potential of the ternary photoanode shows a significant cathodic shift of 130 mV compared with the BiVO 4 photoanode. Moreover, the measured incident photon-to-current efficiency (IPCE) value reaches 50.52% at λ = 420 nm. The improvement is attributed to the type-II heterojunction formation that enhances the separation efficiency of electron/hole and the rGO decoration that accelerates the electron transfer and provides more active sites for gas adsorption. A novel ternary photoanode of BiVO 4 /NiO/rGO was successfully designed and fabricated by simple method. The photoanode not only extends the visible light absorption range and increases photocurrent density but also enhances IPCE and ABPE value, which is attributed to the enhanced charge separation and surface reaction dynamics of p-n heterojunction formed by BiVO 4 /NiO and the acceleration of electron transport by rGO. [Display omitted] • The BiVO 4 /NiO/rGO photoanode was synthesized by simple methods. • PEC properties of ternary photoanode are significantly enhanced compared with BiVO 4. • The enhancing is attributed to the modification of NiO and the addition of rGO. [ABSTRACT FROM AUTHOR]