Preparation Of Heterojunction Photoelectrode And Its Application In Photocatalytic Wasterwater Fuel Cell

Recycling wastewater is one of the hot spots in the research of water pollution control at present.An effective way to recycle wastewater is to recover the rich chemical energy.Photocatalytic fuel cell is a newly developed technology in recent years,which can convert chemical energy into electrical energy through semiconductor anode catalyzing oxidation of organic matter and obtaining electrons.However,the existing photocatalytic fuel cells still have several issues,including the response of the light anode to visible light,the development of efficient cathode materials.In this paper,a novel photocatalytic wastewater fuel cell system was designed.For the photoanode,a novel BiVO₄/TiO₂ NTs photoanode and BiOI/WO₃ NFA photoanode with a heterojunction structure were fabricated.For the photocathode,a novel ZnO/CuO b-NWs photocathode is proposed in this paper.On this basis,the photoanode and photocathode are assembled into PFC,and the properties of PFC are also studied.In terms of photoanode,BiVO₄/TiO₂ NTs electrode was prepared through depositing BiVO₄ on TiO₂ by spin coating.The visible light absorption and photocurrent of TiO₂ electrode modified by BiVO₄ have been improved.The photocurrents of BiVO₄/TiO₂ NTs,BiVO₄/TiO₂（N₂）NTs photocathode were 2.06mA/cm² and 2.73mA/cm²,respectively.In addition,when BiVO₄/TiO₂（N₂）NTs was used as the photoanode,the degradation rate of methylene blue could reach 91.8%,and remained relatively stable during PFC application.WO₃ was prepared by hydrothermal method,and BiOI/WO₃ NFA heterojunction was formed by depositing BiOI on WO₃ by impregnation hydroxylation.The morphology of BiOI/WO₃ NFA nanowires was observed by scanning electron microscopy（SEM）.BiOI/WO₃ NFA was confirmed by XRD,XPS and other tests.At the same time,the visible light absorption,photocurrent and degradation performance of BiOI/WO₃ NFA have been improved.The experimental results show that the absorption band edge of BiOI/WO₃ NFA is about 600 nm,and the absorption intensity is obviously enhanced.The photocurrent of BiOI/WO₃ NFA was improved to 2.5 mA/cm²,and the degradation rate of methylene blue was also increased to 92%,which was stable in the degradation process.In terms of photocathode,CuO NWs was first obtained by wet chemical method,then ZnO NWs was deposited on CuO NWs by spin coating to obtain ZnO/CuO/FTO b-NWs nanostructured photocathode.The surface morphology,lattice structure and absorption spectrum of ZnO/CuOb-NWs were confirmed by TEM,XRD and DRS analysis.The photocurrent of ZnO/CuO b-NWs electrode was improved obviously than that of pure CuO NWs electrode by photoelectrochemical test.In this paper,the visible light responsive BiVO₄/TiO₂ NTs photoanode and ZnO/CuO b-NWs photocathode were assembled into a photocatalytic wastewater fuel cell,and their properties were studied.The results showed that the efficiency of visible light utilization and the degradation efficiency of glucose,phenol,methyl orange,congo red,methylene blue and tetracycline were enhanced significantly by double electrode system.