Thin p-type NiO nanosheet modified peanut-shaped monoclinic BiVO4 for enhanced charge separation and photocatalytic activities

Abstract

BiVO₄ (BVO) is an excellent semiconductor material with a suitable band gap for photocatalytic applications. The serious challenge is to solve the problem of electron–hole pair recombination in pure BVO. Herein, we reported the synthesis of NiO nanosheet coated BVO and the NiO/BVO heterojunction improved the photocatalytic activity effectively, while an appropriate precursor Ni(NO₃)₂·6H₂O concentration is a key factor for the NiO formation with different morphologies. The enhanced dye adsorption capacity of the composite materials is attributed to the large specific surface area of NiO nanosheets. Moreover, the typical type-II p–n junction structure promoted the separation ability of photogenerated carriers and produced more ˙O₂⁻ and ˙OH⁻ radicals. The prepared NiO/BVO showed much higher photocatalytic activity than pristine BVO and the optimal photocatalytic performance was obtained when the mass percentage of precursors Ni(NO₃)₂·6H₂O and BVO was 60%. The removal efficiency for RhB reached 92%, which was nine times than that of pure BVO.