Preparation And Catalytic Performance Of BiPO₄ Composite Photoelectrode

BiPO₄ photoelectrode has the characteristics of corrosion resistance,chemical stability,non-toxicity,excellent catalytic activity and convenient solid-liquid separation,which is beneficial to repeated recycling.However,it can only respond to the light in the ultraviolet region,has a low-interest rate for solar light and low quantum efficiency,which limits its industrial application process.To solve the above problems,a series of BiPO₄ composite photoelectrode materials were designed and synthesized by a semiconductor composite method.The relationship between structure,morphology and photoelectrochemical performance was studied,and its application performance in the field of pollutant degradation was discussed.?1?BiPO₄/RGO/FTO composite electrode materials were prepared by two-step electrodeposition method.The effects of external bias voltage and electrode deposition time on the degradation of methyl orange by electrode materials were investigated.The experimental results show that when the deposition time of barium phosphate is 45 min and the applied bias voltage is 1.2 V,the composite electrode has the best degradation efficiency of methyl orange,which is about 80%in 5 hours,and which is 2.8 times that of BiPO₄/FTO electrode.The reason for the increased in photoelectrocatalytic activity is mainly that graphene improves the light absorption capacity of BiPO₄,and its good conductivity accelerates the separation efficiency of BiPO₄ electron holes.?2?A series of BiOI/BiPO₄/FTO composite photoelectrode materials were prepared by a simple two-step electrodeposition method.The effects of applied voltage,iodine oxide deposition time and other factors on the degradation of tetracycline were explored.The results show that the BiOI/BiPO₄/FTO composite film electrode has higher PEC oxidation ability than the pure BiOI/FTO and BiPO₄/FTO film electrodes,which are increased by 1.98 times and 2.46 times,respectively.The reason for the improved of photoelectrocatalytic activity is mainly that BiOI improves the light absorption performance of BiPO4,and BiOI with BiPO4 form a p-n heterojunction structure to accelerate the separation efficiency of electron-hole.?3?NiFe-LDH/BiPO₄/FTO composite photoelectrode materials were prepared by two-step electrodeposition.Its composition,crystal morphology and optical properties were characterized.The results show that the composite electrode has better photoelectrochemical performance.The photocurrent density of NiFe-LDH/BiPO₄/FTO electrode is increased by 4 times compared with BiPO₄/FTO,and the water oxidation onset potential is reduced by about 0.3 V.This is because the ferronickel hydrotalcite extends the light absorption range of BiPO₄ to the visible light region,and the heterojunction structure accelerates the electron-hole separation efficiency.