Preparation of CuO/BiVO4 Photocatalyst and Research on Carbon Dioxide Reduction

The CuO/BiVO4 heterojunction photocatalyst was constructed based on decahedral bismuth vanadate (BiVO4) and copper oxide (CuO) nanoparticles. The morphology, structure and optoelectronic properties of the catalysts were analyzed by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), ultraviolet-visible absorption spectroscopy (UV-Vis), photocurrent response spectroscopy (I-t), electrochemical impedance spectroscopy (EIS) and fluorescence emission spectroscopy (PL). The results show that CuO nanoparticles are uniformly supported on the surface of BiVO4, and the content of CuO can be adjusted by con. trolling the amount of copper source. The content of CuO has a great effect on the visible light absorption capacity and the separation efficiency of photogenerated carriers of the CuO/BiVO4 heterojunction. The photocatalytic CO2 reduction performance of CuO/BiVO4 heterojunction under gas-solid reaction system was investigated. The results showed that the main products of photocatalytic reduction of CO2 were CO and CH4. With the increase of CuO content,the yield of CO decreased gradually, while the yield of CH4 increased first and then decreased. The CO and CH4 yields of the optimized catalyst CuO/BiVO4 were 0.62 and 1.81 mu mol center dot g(-1)center dot h(-1), respectively, and the selectivity to CH4 reached the maximum value (93%). Band structure analysis and electron paramagnetic resonance (EPR) test results show that the transfer of photogenerated charges in CuO/BiVO4 conforms to the Z-type transfer mechanism. The formation of the Z-type heterostructure promotes the separation of photogenerated electrons and holes and enhances the redox capacity of the catalytic system.