In-situ Deposition Of Ag₃PO₄ On Single-crystalline TiO₂ Nanosheets For Highly Efficient Photocatalyst

With worsening of environment pollution,photocatalytic technology has received extensive attention over decades due to their being environment-friendly,energy saving and high efficiency.And photocatalysts of high efficiency,low price and great stability are vital to this technology.In this research,anatase single-crystalline TiO₂ nanosheets?TNS?dominated by exposed?001?facets acted as carriers.Then Ag₃PO₄,which is responding to visible light and shows strong photocatalytic performance,was deposited onto the surfaces of TNS in order to acquire a PN heterojunction photocatalyst.And photocatalytic activity in the degradation of rhodamine B?Rh B?was investigated.Then the possible mechanism for the photocatalytic degradation of RhB was presented.Firstly,TNS with a large percentage of?001?facets was synthesized via hydrothermal method.Then Ag₃PO₄/TNS was fabricated through in-situ deposition of Ag₃PO₄ on TNS.The morphology,compositions and optical properties of the Ag₃PO₄/TNS photocatalyst were analyzed.It was shown that TNS has uniform size of100 nm and Ag₃PO₄ particles are about 200 nm in size.The Ag₃PO₄ nanoparticles deposited on the TNS surface are 10.06±2.09 nm in size.XRD spectra showed that TNS is anatase phase,Ag₃PO₄ is pure and all materials possess high degree of crystallinity.FTIR and XPS results confirmed that there is a strong interaction between Ag₃PO₄ and TNS,that is,heterojunction exists.UV-Vis DRS exhibited that Ag₃PO₄/TNS heterojunction is strongly responsive to visible light.And more Ag₃PO₄loaded results in larger redshifts.PL analyses showed that the recombination of photogenerated holes?h⁺?and electrons?e^-?of Ag₃PO₄/TNS heterojunction is largely inhibited,compared to pure Ag₃PO₄ and pure TNS.And Ag₃PO₄/TNS-60 has the lowest recombination rate.Secondly,the as-prepared materials were investigated in the photocatalytic degradation of RhB under visible light.After adsorption equilibrium experiments of materials,the degradation tests of 10 mg/L RhB over 1 g/L catalysts were carried out.It was shown that Ag₃PO₄/TNS composites have enhanced adsorbability and photocatalytic abilities.Above all,the RhB degradation efficiency is 99.11%after 50min of sunlight irradiation,and 85.8%after three cycles over Ag₃PO₄/TNS-60.Finally,a possible mechanism for the photocatalytic degradation of RhB was explored.Trapping experiments determined that h⁺and·O₂^-are responsible for degradation process.And Ag₃PO₄/TNS photocatalyst belongs to a type-II heterojunction,whose proper band alignment greatly reduces the recombination of h⁺and e^-.