Photocatalytic reduction of carbon dioxide with water on InVO₄ with NiO cocatalysts

InVO₄ was synthesized by solid-state reaction method using In₂O₃ and V₃O₄ as the starting materials. NiO was added as the cocatalyst. The catalysts were characterized by powder X-ray diffraction, scanning electron microscope, and ultraviolet-visible spectroscopy. The photocatalytic reduction of CO₂ with water was carried out in a Pyrex reactor with KHCO₃ aqueous solution bubbled with CO₂ gas under visible light illumination. Many pinholes were observed on the InVO₄ particles after loading with NiO cocatalyst. The band gap of NiO/InVO₄ was lower than that of InVO₄ due to the formation of subband in valence band by creating more defect sites on the surface of InVO₄. Both NiO/InVO₄ and InVO₄ can reduce CO₂ to methanol under visible light irradiation. The reaction rate increased with an increase of the loading of NiO cocatalysts.