Construction Of Immobilized Direct Z-scheme V₂O₅/FeVO₄/430-SSF Composite Film And Study On Photocatalytic Activity

Since the 21st century,energy shortage and environmental pollution problems have become increasingly serious.Therefore,it is very necessary to look for an efficient,clean and sustainable energy to replace fossil energy.Hydrogen has the advantages of high energy density and renewability.And hydrogen is easy to store and transport.In addition,only water is produced when hydrogen is combusted.Therefore,it is one of the most ideal alternative energy sources.Among various existing hydrogen production technologies,the photocatalytic technology can utilize light energy to carry out water splitting for hydrogen production.It is considered one of the most promising technologies due to its potential to convert and store readily available solar energy into chemical energy.The photocatalytic technology can not only be used to produce clean energy,such as water splitting to produce hydrogen,but also be widely applied for organic pollutants degradation.Among them,the direct Z-scheme photocatalytic system has attracted extensive attention because of its high photocatalytic ability.Therefore,in this study,the immobilized direct Z-scheme V₂O₅/Fe VO₄/430-SSF photocatalyst composite films were prepared by using simple sol-gel spin-coating and incomplete solid phase chemical combustion methods.Among them,430 stainless steel foil is not only the carrier of direct Z-scheme V₂O₅/Fe VO₄ photocatalyst composite film,but also the transmission channel of photogenerated electrons.In this way,the photocatalytic degradation and hydrogen production reactions can be carried out on the both sides of 430 stainless steel foil,realizing the effective separation of hydrogen and carbon dioxide.The crystal structure,microstructure,elemental composition and photoelectric property of the prepared immobilized direct Z-scheme V₂O₅/Fe VO₄/430-SSF photocatalyst composite films were investigated by using a series of characterization methods.In addition,the experiments of the photocatalytic degradation of tetracycline and the production of hydrogen were also carried out to explore the influences of different preparation conditions,use times and other factors on the photocatalytic activities of immobilized direct Z-scheme V₂O₅/Fe VO₄/430-SSF photocatalyst composite films.The results show that the immobilized direct Z-scheme V₂O₅/Fe VO₄/430-SSF photocatalyst composite film prepared at 550℃for 4.0 h with two layers of V₂O₅ sol has the best photocatalytic activity.Under simulated sunlight irradiation for 120 min,the photocatalytic degradation ratio and hydrogen production amount could reach77.53%and 370.81μmol/dm²,respectively.Moreover,the immobilized direct Z-scheme V₂O₅/Fe VO₄/430-SSF photocatalyst composite film has good stability and reusability.Finally,a possible reaction mechanism of photocatalytic tetracycline degradation and pure hydrogen production caused by immobilized Z-scheme V₂O₅/Fe VO₄/430-SSF photocatalyst composite film was proposed.It is hoped that this work could provide some guiding suggestions to designing a photocatalyst composite film for efficient photocatalytic degradation of organic pollutants with simultaneous production of pure hydrogen on a large scale in the future.