The Research On The Photocatalyst Performance Of Multilayered Graphene Films Loaded With CdS Nanorods Arrays

Energy crisis and environmental pollution are tow serious problems that humanity is now facing today.Photocatalysis,a new catalytic technology,can convert low density solar energy into high density chemical energy.With a suitable photocatalyst,photocatalysis realize hydrogen generation form water,photocatalytic reduction and photocatalytic degradation using solar energy,providing a feasible solution for solving energy crisis and environmental pollution.CdS,with narrow band gap of 2.4 eV,has a suitable conduction band position which corresponding well with the visible spectral range of sunlight.However,there are two major drawbacks of CdS,high photo-induced carries recombination rate and serious self photocorrosion,which have largely hindered the extensive practical application of CdS.In order to solve the above problems,here,with the enhancement of light scattering and conduction electrons directly of one-dimensioanl nanorods arrays and the high conductivity of graphene,CdS nanorods arrays were designed to be grown on the interlayers of multilayered graphene film.By building heterostructure,elements doping and ZnO coating strateges,combing with the advantages of directional electrons on one-dimensioanl semiconductor materails,the CdS nanorods arrays showed the better photocatalytic performance and stability after modification.The main contents and conclusions are as follows.?1?With ZnO seed on graphene,a heteroepitaxial grew of the ZnS/CdS NRAs via a facile hydrothermal process and turned into the ZnS/CdS NRAs/rGO membrane.The sample could be found that many nanorods with an average length of 400 nm and a diameter of 120 nm have small caps on their tops,which were composed of ZnS and CdS respectively.The photocatalytic and photo electrocatalytic activity of ZnS/CdS NRAs/rGO and CdS NRAs/rGO were compared by different characterization.Under visible light conditions,ZnS/CdS NRAs/rGO films showed the better and more stable photocatalytic performance.The hydrogen production was 10.36 mmol·g^-1·h^-1 loaded with Pt nanoparticles.In addition,this paper explained the photocatalytic hydrogenation mechanism of ZnS/CdS NRAs/rGO by the comparison of the performance difference of the co-catalyst position.?2?Ni can be easily achieved doping into CdS when prepared the reflooding solution of CdS with Ni²⁺added,because of stable metal complex.This paper analyzed the morphology,composition and photocatalytic for hydrogen production of Ni-doped CdS NRAs/rGO.The results displayed that Ni element had doped into CdS successfully and improved the hydrogen production performance.In addition of visible light,without metal particles deposited,the hydrogen evolution of Ni-doped CdS NRAs/rGO reached 9.5 mmol·g^-1·h^-1,which was twice as much as the CdS NRAs/rGO film.?3?This paper provided two steps to coated CdS NRAs/rGO with ZnO,firstly by hydrothermal and then solvothermal method.With the increase of ZnO loaded,more and more flaps were covered on the surface on the CdS NRAs,which restricted the absorption and utilization of the photocatalyst.In the condition of 5 mM of zinc acetate in absolute ethanol and solvothermal treated for 5 hours,ZnO/CdS NRAs/rGO showed the best photocatalytic performance for 4-nitrophenol reduction.After 40 minutes illumination,the highest conversion reached 98.7%and the reaction rate constant was 0.1065 min^-1 with ZnO/CdS NRAs/rGO.Coated with ZnO particles,CdS NRAs were protected from photocorrosion.