Morphology Regulation And Photocatalytic Performance Of Ba-Doped Ta₃N₅ Photoanode

Semiconductor-based photocatalytic overall water splitting for hydrogen production is an ideal way to convert solar energy to chemical energy and has inspired extensive interest in the past few decades.Towards this,hundreds of semiconductors have been reported for potential solar water splitting,but most of them are only active under UV light irradiation.To achieve highly efficient solar-to-chemical energy conversion,overall water splitting on photocatalysts harvesting visible light with longer wavelength is desirable.Tantalum nitride with high theoretical solar energy conversion efficiency have been widely used in photocatalytic water splitting.However,the severe recombination of photogenerated carriers always restricts their actual photocatalytic reaction efficiency.In this dissertation,in order to find the best morphology of the Ba-Ta:;Ns which are represented,nitridation of two steps strategy and Ta foils was put forard(1)Ba-doped Ta;Ns of BaTaO2N particle are preparaton by nitridation of two steps strategy and the microscopic morphology could be controlled,shifting the morphology from irregular structures into cubic strutures through adjusting mole ratio of the flux and changing time of the nitridation.The reasonable structure of the synthesized samples would reduce the defect and restrain the recombination of photogenerated carriers,thereby separating the photo-generated electron-hole pairs more effectively.That can enhance the photocurrent and avoid self-erosion effect of the photoanode which hold longer service lifetime.There is no doubt that the morphology control have positive meaning in the field of photoelctrochemistry water splitting.(2)ABa-doped TaBa.Ta3N5 photoanode have been successfully constructed by means of that Ta foils were oxidized in air and were then nitrided in flow incompany with the fluxnd and exhibited a significant improvement.The Ta|Ba-Ta3N5 photoanode that barium ions are partially doped into Ta3NS to inhibit the formation of defects have Ta3N5 and BaTaO2N5 in addition that the conduction band and valence band of BaTaO2N are more negative than Ta3N5.In the event that can make up Ta3N5/BaTaO2N heterostructure,thestructures favour the enhancement of charge separation efficiency as well as the promotion of the saturation photocurrent.