Preparation And Properties Of BiVO₄ Photoanode

The visible photocatalytic material bismuth vanadate?BiVO₄?photoanode is a kind of semiconductor material which uses solar energy and produces photocatalysis reaction.It is widely used in Photodegradation of aquatic hydrogen and photocatalytic degradation of pollutants.However,due to its short band gap,pure BiVO₄ has a serious recombination of photogenerated electron hole pairs,and the actual photocurrent density is far lower than its theoretical value.Therefore,it is of great significance to improve the photoelectric properties of BiVO₄ photoanode.In this paper,the pure BiVO₄ photoanode was prepared on conductive glass by electrochemical deposition and annealing.Subsequently,PANI/BiVO₄ photoanode was prepared by electrochemical deposition on the surface of pure BiVO₄ photoanode.CuO/BiVO₄ photoanode was prepared by doping CuO on the surface of BiVO₄ photoanode by thermal decomposition.Finally,Au/CuO/BiVO₄ photoanode was prepared by ion sputtering on CuO/BiVO₄ photoanode.X-ray diffraction?XRD?,infrared absorption spectroscopy?FT-IR?,Raman Scattering Spectroscopy?Raman?,photoelectron spectroscopy?XPS?and field emission scanning electron microscope?FE-SEM?were used to analyze the phase and structure of the photoanode.The photovoltage,photocurrent density,impedance and photogenerated electron lifetime of the photoanode were measured by a self built photoelectric test system.The main results are as follows:1.When the electrodeposition time is 10 minutes and the heat treatment temperature is 475?,the pure BiVO₄ photoanode has the best photoelectric performance.Its photocurrent density is 0.56 mA/cm²,which benefits from the optimization of the basic process of photoanode.2.The photocurrent density of PANI/BiVO₄ photoanode is 0.73mA/cm² when PANI electrodeposition time is 30s,which is 30%higher than that of pure BiVO₄ photoanode.The addition of PANI can improve the photoelectric pressure difference of BiVO₄photoanode,reduce the interface charge transfer resistance of BiVO₄ photoanode,and increase the photocurrent density of PANI/BiVO₄ photoanode.3.When the CuO content is 0.4wt%,the maximum photocurrent density of CuO/BiVO₄ is 0.85mA/cm²,which is 52%higher than that of pure BiVO₄.The addition of CuO can improve the photoelectric pressure difference of photoanode and reduce the interfacial charge transfer resistance of photoanode.4.The photocurrent density of Au/CuO/BiVO₄ photoanode?1.5mA/cm²?is 167%higher than that of pure BiVO₄ photoanode and 76%higher than that of CuO/BiVO₄photoanode.The unique Schottky barrier formed by the combination of Au and BiVO₄inhibits the recombination of photogenerated electron hole pairs,and the p-n junction formed by the combination of CuO and BiVO₄ also inhibits the recombination of photogenerated electron hole pairs.Under the joint action of Au and CuO,Au/CuO/BiVO₄photoanode has much higher photoelectric performance than BiVO₄ photoanode and CuO/BiVO₄ photoanode.