Low-temperature Preparation And Performance Of Bi_xY_1-xVO₄ Solid Solution For Photocatalytic Hydrogen Production

The energy crisis and environmental issue have been considered as two major problem in our society.Hydrogen as a clean energy plays an indispensable role in the energy resources.In the existing techonologies for hydrogen production,transforming soalr energy into hydrogen energy has been accounted as the most potential way for the development and application,in which,developing cheap and efficient photocatalysts for water splitting has become a matter of great issue.In this paper,we synthesize Bi_xY_1-xVO₄ solid solution with high photocatalytic performance and good stability through a low temperature preparation method and studied the photocatalytic activity of these samples.We prepared Bi_xY_1-xVO₄ solid solution with porous surface by molten salt method.Through the XRD,UV-Vis DRS,BET,SEM and ICP results,the influence of calcination temperature and the weight ratio of the precursor to the salt on the catalyst crystal structure,band edge,specific surface area and elements ratio have been investigated.The different performances of photocatalytic water splitting were also discussed.The porous structure on the surface occurs with the addition of molten salt,which was caused by the evaporation of molten salt at higher temperature.Compared with solid state reaction method,BYV prepared by molten salt method showed better photocatalytic performance,which was due to the lower synthesis temperature and porous structure on the surface.And BYV via 550oC calcination with 5:1 as weight ratio showed the highest photocatalytic activity,by which the amounts of hydrogen and oxygen produced were about 163μmol·h^-11 and 68μmol·h^-1 respectively.Bi_xY_1-xVO₄ solid solution with regular shape prepared via hydrothermal method was also studied in this paper.Prior to examine the photocatalytic performance,the catalysts were characterized by XRD,UV-Vis DRS and SEM.We investigated the influence of pH,reaction time and component ratio on the structure and performance of catalysts and found the formation of Bi_xY_1-xVO₄ solid solution is affected by the above factors.Lower pH and larger x will promote the generation of monoclinic BiVO₄.The results of performance test showed that the catalysts have the best activity when the Bi_xY_1-xVO₄ solid solution and monoclinic BiVO₄ are coexisted.When the pH=4,the hydrothermal time is 48h and x=0.5,the material holds the best photocatalytic activity,by which the amounts of hydrogen and oxygen produced were about 165μmol·h^-1 and 83μmol·h^-1respectively.The co-catalyst plays an important role in the photocatalytic water splitting.In this paper,we loaded Pt as co-catalyst through photo deposition method and studied the influence of loading amount to the activity.The result showed that loading amount of 1%holds the best activity.Besides,we also investigated the influence of different co-catalyst and loading way to the photocatalytic performance.