Nanoplasmon-Based Catalytic Sensing

Noble metal nanoparticles?NPs?have been the subject of extensive research in the nano-technology,mainly owing to their unique physical and chemical properties.Indeed,the free electron gas of such NPs features a collective oscillation upon illumination in the visible part of the spectrum.This feature is named as surface plasmon resonance?SPR?,and the field of research that studies the fundamentals and applications of SPR is known as nanoplasmonics.At present,noble metal nanoparticles have been widely used as effective catalyst materials due to their unique LSPR effect in the field of heterogeneous catalysis research.In the biochemical category,noble metal nanoparticles exhibit excellent enzymatic activity due to their unique size effect and have been used for the detection of molecules,such as glucose,which solves the difficulty of storage and highly cost for the traditional natural enzyme molecules.The appearance of heterogeneous Fenton catalysts that involving nano-plasma in the aspect of pollution treatment and water quality detection,improves catalytic activity effectively on organics compared with the traditional Fenton catalyst materials,and also solves the secondary pollution and recycling treatment of the catalyst itself.At the same time,the sensitivity of metal nanoplasmon to light makes it widely used in the energy and environmental fields.The nanoplasmon participate in photocatalyst materials or photocatalytic reaction not only enhance the activity of the original photocatalysts,but also broadens the band range of excitation light that can be applied to the photocatalysts,and change the wavelength response range of some photocatalysts from the ultraviolet to the visible light.Furthermore,as all known,the SPR effect of nanoplasmon manifests itself as a strong absorption peak in the Uv-Vis spectrum.This phenomenon on spectrum allows noble metal nanoparticles to be used to construct optical sensors based on the SPR effect.At the same time,this SPR sensor can provide more in-depth and detailed exploration for the research of catalytic reaction.From now on,common SPR sensors used for the detection of catalytic reactions are measuring the change absorption peaks of nanoparticles,which responds to the dielectric property's change of environmental media.However,this external change brings great uncertainty to the sensing results,which also restricts the development of catalytic reaction research.Based on the research of catalysis and sensing,in this paper,we proposes a new catalytic reaction-based nanoplasmonic sensor and a new monitoring method based on the deficiencies of traditional SPR sensor.The main contents are briefly described as follows:?1?Gold?Au?nanoplasmon was used as glucose oxidation enzyme and used as catalyst for glucose catalytic oxidation reaction.Au nanoplasmons with different sizes were prepared and used as catalysts.Based on their catalytic activity,Au nanoplasmons were used as sensor for the construction of glucose catalytic sensing system.Furthermore,Au@SiO₂ nanoplasmon film was prepared for the disadvantages of liquid catalyst materials,such as easy contamination and instability.Under the protection of SiO₂,Au nanoparticles not only retain excellent activity,but also increase their thermal stability,ensuring the size of Au nanoparticles after high temperature treatment.Then,Au@SiO₂ nanoplasmon film was used as a sensor device based on the catalytic activity for the construction of glucose catalytic sensing system.?2?Au nanoplasmon was used as a Fenton catalyst for the Fenton-catalyzed oxidation of organics.C₆₀@Au and Au@Fe₃O₄ nanoplasmon films were prepared and studied,respectively.The catalytic activity of Au NPs was be inhibited due a larger size of as-prepared Au nanoparticles,which was used for a clear spectral signal.The problem of catalytic activity was solved by the introduction of C₆₀.Other side,the Au NPs composited with Fe₃O₄ further improved the Fenton catalytic activity of Au nanoparticles.Then,both nanoplasmon films were used as a sensor device for the Fenton catalytic sensing system based on the Fenton catalytic activity.?3?Au-TiO₂-C₆₀ and C₆₀/Ag/AgCl film were prepared.Both nanoplasmon films were used as photocatalyst for the photocatalytic oxidation of organic materials.In addition,as a photocatalyst material,it is also used as a sensor device to construct a complete organic photocatalytic sensing system.?4?A change of the LSPR absorption,during the catalytic reaction,is defined as"plasmonic swing”.The swing frequency?f_s?is used as a sensing signal,instead of the traditional method with the detection of LSPR absorption peak.This new method avoids the environment interfere effectively and improves the accuracy of the sensor.