Catalytic Sensing Base On Au@TiO₂ Nanoplasma

In recent years,noble metal nanomaterials have attracted great attention due to their unique physical and chemical properties.There are a large number of free electrons in the metal nanoparticles,and when excited by visible light,these free electrons will generate a collective oscillation,and the oscillation behavior of these electrons are called surface plasmon resonance,that is,SPR.When the metal nanoparticles are irradiated by electromagnetic waves having a wavelength larger than the size of the nanoparticles,the free electrons of the metal generate an oscillation called partial surface plasmons?LSPs?,that is,LSPR.The collective oscillation of electrons is the basis for the catalysis and sensing of nanoplasma.For example,the sensitivity of nanoplasma to light makes it widely used in environmental protection and energy fields.Photocatalysts based on nanoplasma material not only improve the catalytic activity of traditional semiconductor photocatalysts,but also extend the response range of semiconductor materials from the ultraviolet to the visible light,allowing greater use of the energy of sunlight.Based on the existing research of catalysis and sensing,this paper proposes a new nano-plasma sensing monitoring method based on catalytic reaction.The main contents are briefly described as follows:?1?Because the material,structure,and morphology of the nanoparticles are very important in adjusting the performance of the sensor,we successfully synthesized a new multinuclear core-shell material AuNPs@TiO₂ by mixing the prepared 3.5 nm AuNPs with TiF₄ aqueous solution for 3 h under Under hydrothermal reaction.And a plurality of 10-15 nm gold nuclei are uniformly dispersed in the nanocomposite,not only the plasmon resonance effect of the gold nanoplasma extendthe TiO₂ to the visible light region,but also the plurality of small-sized nuclei can be effectively increased the contact area between Au and TiO₂,allowing the hot electrons excited by the plasma oscillation can be transferred to the adjacent titanium dioxide more quickly,achieving more efficient electron-hole separation.The degradation of Rhodamine B by this nanocomposite photocatalyst can reach 89.7%,compared with the control experiment?catalyzed degradation of rhodamine B by TiO₂,13.1%?and the blank experiment?self-degradation of rhodamine B under illumination,5.8%?photocatalysis The effect issignificantly improved.?2?The prepared AuNPs@TiO₂ nanoplasma material was applied to the photocatalytic monitoring of catalytic degradation of rhodamine B and phthalates.The peak position sway frequency of the nanoplasma caused by electron transfer in the catalytic process is used as a sensing signal.The results show that the oscillating frequency of the plasma peak during the photocatalytic process can effectively reflect the velocity in the catalytic process.The sensor realizes real-time monitoring of the progress of the catalytic reaction,which is more intuitive and efficient.Moreover,since the response signal of this sensor is caused by electron transfer during the reaction,the uncertainty of the previous sensor due to the response to changes in the surrounding medium is solved.This is more conducive to the practical application of the sensor.