In-situ Monitoring Of CO Electrocatalytic Processes At Nano-catalyst Interface By Shell-isolated Nanoparticle-enhanced Raman Spectroscopy

Since the discovery of Raman scattering effect,Raman spectroscopy has gained wide attention as a fingerprint recognition information technology.The development of surface-enhanced Raman spectroscopy(SERS)has further promoted Raman spectroscopy.SERS is widely used in the adsorption process of metals and substances and the oxidation of metals by virtue of its non-destructive,anhydrous interference,and its ability to provide a large amount of fingerprint information at low wavenumbers(below 1000 cm-1).However,In order to provide a guide for the synthesis of catalysts,there is an urgent need to monitor the catalytic process of the catalyst in situ.However,there are still many problems for the in-situ monitoring technology of nanocatalyst catalytic processes,due to the limitation of nanocatalyst morphology,SERS signals cannot be directly obtained.In 2010,our research group developed a shell-insulated nanoparticle-enhanced raman spectroscopy(SHINERS).The invention of the shell-insulated nanoparticle overcomes the two major problems:universality of the material and the universality of the appearance,if the nanocatalyst and shell-insulated nanoparticles can form a new structure-satellite structure through self-assembly.On the one hand,they can exert the catalytic performance of the catalyst.On the other hand,the shell can be used to isolate the electromagnetic field enhancement capability of the nanoparticles,so that the catalytic reaction process of the nanocatalyst can be tracked in situ.This strategy enables direct non-interference monitoring of non-SERS materials.In this paper,a variety of nano-synthetic and characterization techniques are used to precisely regulate the composition,size,morphology,and structure of nano-catalysts.In combination with in-situ SHINES spectroscopy,they are related to the intermediate species and catalytic performance of their electrocatalytic reactions.The relationship between the catalytic reaction and the reaction mechanism of the nanocatalyst was investigated on the molecular level.The main research contents of this paper are as follows:(1)The process of catalytic oxidation of CO with different proportions of PtFe alloy nanoparticles was studied.The influence of the change of Fe molar ratio on the catalytic performance of CO was investigated using EC-SHINERS technique.It was found through experiments that the addition of Fe was beneficial to weaken the bond of CO and Pt,thereby the catalytic performance of the catalyst can be improved.(2)PtRu catalysts with different structures were designed:PtRu alloy and PtRu core-shell structure.The performances of CO and methanol catalyzed by these two configurations of PtRu catalysts were compared,with the aid of EC-SHINERS technology,Ru was studied to improve catalyst performance.It was found that the addition of Ru can greatly enhance the catalytic oxidation of CO and methanol by the catalyst,mainly because Ru exposed on the surface can provide a large number of oxygen-containing active species.