Study On Modification And Piezo-photocatalytic Activity Of ZnO Nrs On Al₂O₃ Foam Ceramic Substrate

As a typical wide band gap semiconductor material,ZnO has the advantages of high electron mobility,stable chemical properties,various preparation methods and biosafety,as well as piezoelectric properties,so it has great application potential in the field of photocatalytic degradation,but the rapid recombination of photogenerated carriers limits its photocatalytic activity.In order to improve the photocatalytic activity of ZnO,ZnO nanorods（ZnO NRs）were grown on Al₂O₃ foam ceramic substrate.ZnO piezoelectric field was excited by low energy density.ZnO nanorods were modified by atmosphere treatment,La doping and CuS composite.The effect of piezoelectric field intensity on the photocatalytic performance of the samples was studied,and the mechanism of enhanced piezoelectric photocatalytic activity was explored.ZnO NRs on Al₂O₃ foam ceramic substrates was prepared by hydrothermal method.The samples were heat-treated in air,vacuum and oxygen atmosphere respectively to investigate the effect of non-stoichiometric defects on the phase structure and morphology of ZnO.The results show that when the seed solution is impregnated for 100 times,the morphology of the ZnO NRs is uniform,the length is about 3.5～4μm and the diameter is 150～200nm.Compared with the air atmosphere heat-treated ZnO（A-ZnO NRs）,the photocatalytic degradation efficiency of methyl orange solution by vacuum atmosphere heat-treated ZnO（V-ZnO NRs）increased by 20.19%,and the piezoelectric photocatalytic efficiency increased by 100.02%.It is proved that the oxygen vacancy（Vo）defect can improve the photocatalytic activity of ZnO.La-doped ZnO NRs was synthesized by one-step hydrothermal method,and the effects of La doping concentration on the structure,morphology and photocatalytic activity of ZnO were investigated.The results show that La doping can lead to the redshift of the absorption edge of ZnO.When the doping amount of La was 3mol%,the photocatalytic performance and piezoelectric photocatalytic performance of ZnO NRs were significantly improved.compared with undoped ZnO NRs,the photocatalytic performance and piezoelectric photocatalytic performance were improved by 55%and 81.45%,respectively.CuS nanoparticles were uniformly loaded on ZnO NRs by continuous ion layer adsorption reaction（SILAR）to form pmurn junctions.The effects of CuS loading on the morphology,optical absorption and catalytic activity of ZnO were investigated.The results show that CuS/ZnO NRs has strong light response in ultraviolet and visible light region.The piezoelectric photocatalytic activity of CuS/ZnO NRs is enhanced by the coupling of pmurn junction and piezoelectric electric field,and the piezoelectric photocatalytic efficiency of methyl orange in 120min is 98.68%.After five piezoelectric photocatalytic degradation experiments,the catalytic activity retention rate is97.44%,indicating that CuS/ZnO NRs is an efficient and stable photocatalyst.