Synthesis Of One-dimensional Ag₃PO₄-based Nanocomposites And Their Photocatalytic Performance

Photocatalytic water splitting has drawn much attention in the energy and environment research field because of its green,no pottllution and sustainable recycles,which is considered to be one of the effective ways to solve the promblems of pollution and energy crisis.However,it is still faced with some problems,such as the low rate of light harvesting,recycle difficulty,material selection limit,high cost and difficulty in commercial application and so on.Hence,it's very important to exploring new photocatalyst to overcome these difficulties.This paper focused on these problems above and prepared Ag₃PO₄/CeO₂/TiO₂,Ag₃PO₄/Pt/SiC and Ag₃PO₄/Pt/CeO₂/TiO₂ photocatalysts by the sample materials of Ag₃PO₄,TiO₂,CeO₂,SiC and Pt.Their microstructure,photocatalytic water splitting and degradation performance and mechanism were deeply studied and discussed.Relevant experimental results were as follows:?1?Ag₃PO₄/CeO₂/TiO₂ branch nanowires were synthesised by the deposition of Ag+ and PO43-ions in turn on the surface of CeO₂/TiO₂ branch nanowires prepared by hydrothermal and annealing methods.Then we identified the hierarchical structure of nanowires and found that 2⁵ nm Ag₃PO₄ nanoparticles were uniformly loaded on the surface of CeO₂/TiO₂ branch nanowires by XRD,SEM,TEM and XPS.In the photocatalytic water splitting test without sacrifice argent,the triple system Ag₃PO₄/CeO₂/TiO₂ composite showed oxygen evolution performance,but can't produce hydrogen.Through photocurrent and photoluminescence?PL?spectra measurements,we found that the photocatalyst has excellent carrier separation/transmission performance,which means that there exist very strong synergy effect among the composits of CeO₂,TiO₂ and Ag₃PO₄.Through the band analysis,we think that a new type of Z-scheme heterostructure was formed between the type-II composite of CeO₂/TiO₂ and Ag₃PO₄.Moreover,the type-? heterostructure of CeO₂/TiO₂ not only could enhance the carrier separation/transmission,inhibit the photorecombination,also could further strengthen the synergistic effect of the new Z-scheme heterostructure with Ag₃PO₄,which further enhanced the carrier separation/transmission and suppress backward reaction and caused the oxygen evolution of the triple system under the photocatalytic water splitting test without sacrifice agent.?2?Based on the experimental research contents of the first part,in this article,we prepared Ag₃PO₄/Pt/CeO₂/TiO₂ nanocomposite by loading Pt and Ag₃PO₄ nanoparticles in turn on the surface of CeO₂/TiO₂ branch nanowires through the method of hydrothermal and in-situ precipitation.And the photocatalytic degradation performance Ag₃PO₄/Pt/CeO₂/TiO₂ and the possible effect of Pt nanoparticles to the new Z-scheme composite Ag₃PO₄/CeO₂/TiO₂ were studied and discussed.By XRD,SEM and TEM,we ensured the hierarchical microstructure of this composite that 2⁵ nm nanosized Pt and Ag₃PO₄ nanoparticles were uniformly distributed on the surface of CeO₂/TiO₂ branch nanowires.In the photocatalytic degradation experiments,the Ag₃PO₄/Pt/CeO₂/TiO₂ photocatalyst exhibits better performance than the new Z-scheme composite Ag₃PO₄/CeO₂/TiO₂.Through photocurrent and photoluminescence?PL?spectra measurements,it suggested that the Ag₃PO₄/Pt/CeO₂/TiO₂ composite exhibited more excellent carrier separation/transmission capacity and more efficient ability in restrain the photorecombination.For this phenomenon,it may be attribute to the co-effect of Pt nanoparticles,which act as noble-metal mediater,that accelerated the carrier separation/transmission effect,enhanced the synergistic effect between Ag₃PO₄ and CeO₂/TiO₂ of the new Z-scheme composite Ag₃PO₄/Pt/CeO₂/TiO₂,thus improving the photocatalytic performance!?3?Ag₃PO₄/Pt/SiC nanowires was synthesised by loading Pt and Ag₃PO₄ nanoparticles on the surface of SiC nanowires in turn through the method of hydrothermal and in-situ precipitation.in situ precipitation.From XRD,SEM,TEM and XPS experiment,we ensureed the microstructure of the Ag₃PO₄/Pt/SiC composite that 2 5 nm nanosized Pt and Ag₃PO₄ nanoparticles were uniformly distributed on the surface of SiC nanowires.Under the visible light photocatalytic water splitting test within sacrifice agent,the Ag₃PO₄/Pt/SiCcomposite showed excellent oxygen evolution ability,what's more,the photocatalyst also showed the phorocatalytic oxygen evolution ability,but no hydrogen evolution in pure water.Through photocurrent and photoluminescence?PL?life spectra experiments,it showed that Ag₃PO₄/Pt/SiC composite exhibited strong carrier separation/transmission performance,which means that there was very strong synergy effect among the composits of SiC,Pt and Ag₃PO₄.We think the photocatalytic mechanism of the Ag₃PO₄/Pt/SiC composite should be attribute to Z-scheme heterostructure formed by Pt,SiC and Ag₃PO₄,in which the Pt nanoparticle act as noble-metal mediater combined the photo-generated electrons in the conduct band of Ag₃PO₄ recombine with the holes in the valence band of SiC,so as to improving the stability of Ag₃PO₄ and the water splitting performance.