Z-Ti02 2 / CaTi . 4 O . 9 / Of CaTiO . 3 In Aquatic Photolysis Of Hydrogen (H 2 Research) With Photocatalytic Reduction Of Cr (?) In

Photocatalytic technology is known as “Artificial Photosynthesis”,which realizes the artificial conversion of solar energy to chemical energy.As an advanced technology,it can effectively solve the issue of energy shortage and environmental pollution.Now,photocatalysis still face the challenges,e.g.the low quantum efficiency,the low sunlight utilization.In this paper,the TiO₂?3.2 e V?and CaTiO₃?3.5 e V?with broadband gaps were chosen as the research point.The Z-scheme TiO₂/CaTi₄O₉/CaTiO₃ heterojunction composite photocatalyst was constructed to fully demonstrate the advantages of TiO₂ and CaTiO₃ wide band gap,and improve the separation efficiency of photo-electrons and photo-holes.Then,the good electron transfer media-“reduction of graphene oxide?RGO?” and Cu nanoparticles?NPs?were used to further improve its photocatalytic performance.The main reserch contents are shown as follows:1.The Z-scheme TiO₂/CaTi₄O₉/CaTiO₃ heterojunction composite photocatalyst with a Z-scheme electron transfer mechanism were prepared via a solvothermal-calcination process,which effectively improves the life-time of the carriers.And the Z-scheme electron transfer mechanism makes the e-and h+ have a stronger redox ability compared with traditional heterojunction.The efficient photocatalytic H2 evolution?3.4-160-700-Ca/Ti,25.2814 mmol·h-1·g-1?and photocatalytic reduction of Cr?VI?toward Cr?III?were realized,reaching 1.6 times and 3.1 times of P25?TiO₂,Degussa Co.Germany?,respectively.2.The surface modification of Z-scheme TiO₂/CaTi₄O₉/CaTiO₃ had be realized by RGO,which comes from the reduction of graphene oxide?RGO?through a photoreduction method.The introduction of RGO effectively improves the visible absorption performance of the TiO₂/CaTi₄O₉/CaTiO₃ composite.And the effective contact surface between RGO and TiO₂/CaTi₄O₉/CaTiO₃ composites can effectively promote the transfer of e-of concentrated on CaTiO₃ conduction band to reduce its recombination on the surface or internal of the catalyst.The performance of H2 evolution?1.0 wt% RGO-Ca/Ti,34.7843 mmol·h-1·g-1?and the percent of Cr?VI?reduction are 2.1 times and 3.7 times of the P25,respectively.3.The same photoreduction method was used to reduce Cu²⁺ to Cu nanoparticles?NPs?.Under the influence of the Localized Surface Plasmon Resonance?LSPR?of Cu NPs,the photo-response of TiO₂/CaTi₄O₉/CaTiO₃ composite photocatalyst in the visible light region were improved.The sametimes LSPR promote the e-transfer toward Cu NPs and inhibit its recombination.Thus it achieved non-precious metal cocatalyst for photocatalytic H2 production?0.25 wt% Cu-Ca/Ti,4.90074 mmol·h-1·g-1?,that is 67 times compare with TiO₂/CaTi₄O₉/CaTiO₃?3.4-160-700-Ca/Ti?.Moreover,the Cr?VI?photocatalytic reduction percent of 2.00 wt%-Ca/Ti was 1.24 times higher than that of 1.0 wt% RGO-Ca/Ti.The above research results indicated that the the design of the “Z-scheme” structural,reduction of graphene?RGO?surface modification and non-noble metal Cu nanoparticles deposition are effective strategies for improving the performance of H2 evolution and photocatalytic reduction percent of Cr?VI?,resulting the enhanced quantum efficiency in photocatalytic reaction.