Photocatalytic Preparation Of Solar Fuel With Composite Nano-materials And Its Germicidal Performance

With the rapid development of social economy,the energy crisis continues to intensify and the environmental problems come along.Therefore,developing new energy and managing environmental problems are the most urgent problems in the world.So,the new green photocatalytic technology came into being.The photocatalytic reduction of CO₂ as solar fuel has great prospects for photocatalytic decomposition of water to produce hydrogen（H₂）and photocatalytic sterilization.Photocatalytic semiconductor materials play an indispensable role in photocatalysis,so it is very important for the development of photocatalytic semiconductor materials.In recent years,graphite phase carbon nitride（g-C₃N₄）,a hot semiconductor material,has been studied.In this paper,three kinds of composite nanomaterials were prepared and their photocatalytic properties were studied.The first kind of composite nano-material,black phosphorus quantum dot/g-C₃N₄（BP/g-C₃N₄）composite nanomaterials was synthesized on graphite carbon nitride（g-C₃N₄）matrix by simple electrostatic attraction method.The second composite nano-material Ni/NiO/g-C₃N₄ was prepared by photodeposition under vacuum condition from Ni²⁺and g-C₃N₄.The third kind of oxidized photocatalytic material（Ag/Ga₂O₃）was prepared by electrospinning of Ga₂O₃ and co-catalyst Ag and calcined at high temperature.In this paper,X-ray diffraction（XRD）,)（XRD）,scanning electron microscope（XRD）,（SEM）,transmission electron microscope（TEM）,N₂ adsorption and desorption（BET）,X ray photoelectron spectroscopy（XPS）were used to analyze（XPS）,UV-Vis diffuse reflectance（DRS）,).Fluorescence spectroscopy（PL）was used to characterize and analyze the composite nanomaterials.The kinetics of photocatalytic process of composite nanocrystalline materials was studied by steady-state surface photovoltage spectrum and transient surface photovoltage spectrum.The mechanism of photocatalytic reaction was studied by in situ IR.The results of characterization and experiment showed that the carrier separation efficiency of g-C₃N₄ was improved with loading BPQDs.Compared with the CO formation rate(2.1 mol g^-1 h^-1)of g-C₃N₄,the photocatalytic reduction of CO₂ to CO in BP@g-C₃N₄ composites was more than three times(6.54μmol g^-1 h^-1)higher than g-C₃N₄.And the optimum loading amount of black phosphorus quantum dots was about 1 wt%.In addition,compared with pure g-C₃N₄,BP@g-C₃N₄ composite nanomaterials showed better photocatalytic bactericidal properties.With the support of Ni/NiO,the photoabsorption range of g-C₃N₄ increases and the separation efficiency of photogenerated carriers increases.Ni/NiO/g-C₃N₄ exhibits better activity in photocatalytic reduction of CO₂ and photocatalytic bactericidal.When the Ni/NiO loading was 3 wt%,the amount of CO produced of Ni/NiO/g-C₃N₄ reached 27.91 mol g^-1 after 2 h under light,which was 9 times of the yield of g-C₃N₄.And the selectivity of Ni/NiO/g-C₃N₄ photocatalytic transformation of CO₂ to CO was 87%.The photoabsorption range and carrier separation efficiency of Ga₂O₃ were enhanced with Ag loaded.After 2 h irradiation,the production of 1 wt%Ag/Ga₂O₃ photolysis of aquatic H₂ reached 65.7μmol.This paper provides a new research idea for the development of energy photocatalytic materials.