The Effect Of Metal Nanoparticle’s Plasma Resonance On Photocatalyst Absorption Properties

Noble metal nanoparticles are widely studied because their unique electronic,optical and catalytic properties,which make them have many potential applications in defence science and technology,chemical,catalytic,medical science and so on.The plasma effect of metal nanoparticles can obviously improve the nearby field strength and enhance the absorption of light near the photocatalyst.Because of their small size,nanoparticles are very sensitive to small changes in structural parameters.Therefore,to explore the morphology and size of noble metal nanoparticles on the plasma photocatalytic enhancement effect is very important.In order to study the effect of plasma effect of Ag nanoparticles on the radiation absorption of TiO2,a radiation absorption model of Ag/Al2O3-TiO2 composite film was established and simulated by finite difference time-domain method.For the spherical nanoparticles,the influence of the absorption characteristics of the TiO2 film was calculated and analyzed from three aspects:the Ag-TiO2 spacing,the Ag nanoparticle size and the Ag-Ag spacing.The results show that the local electric field strength around the spherical Ag nanoparticles in Ag/Al2O3-TiO2 composite membrane system is significantly enhanced,the electric field intensity of the TiO2 layer in the composite membrane is enhanced to a certain extent,and the absorption characteristics of the TiO2 film are also enhanced,In different bands,the three factors on the absorption characteristics of TiO2 will have different laws.For non-spherical Ag nanoparticles,the absorption characteristics of several symmetric Ag nanoparticle composite films and the effect on the absorption characteristics of TiO2 film were investigated.The effect of the split direction of split ring on the distribution of local electric field and the absorption of TiO2 influences were analysed.The results show that the local electric field intensity on the sharp edge of metal nanoparticles will be significantly improved,but the angular position of the edges relative to the incident light is very important.Under the guidance of theory,the Ag/Al2O3-TiO2 composite films with different Ag-TiO2 spacing were prepared by magnetron sputtering,and the absorption spectra were measured.The Al2O3-TiO2 membrane model was established.Based on the measured optical constants of the related materials,the absorption spectra of the membrane were simulated and compared with the extinction spectra of the prepared membranes.