Study On Electrocatalytic Reduction Of Nitrate By Electro-deposited Pt Nanoparticles

Nitrate contamination in groundwater has become the major problems for human health and ecological system balance.Electrochemical reduction of nitrate is considered to be the most promising way for the removal of nitrate contamination.Extensive fundamental researches have been focused on improving the activity of the Pt catalyst for nitrate reduction.The previous study on the single crystal Pt electrode has shown that Pt catalyst with different facet shows different activity towards electrocatalytic nitrate reduction.Nevertheless,the morphological effect of polycrystalline platinumon nitrate reduction was seldom studied.In this study,polycrystalline Pt nanoparticles with different morphology synthesized by electrodeposition methods were adopted to study their nitrate reduction behavior,and the mechanism was discussed.Different electrochemical methods(cyclic voltammetry and square wave potential methods)were adopted to electro-deposited Pt nanoparticles onto glassy carbon(GC)for model study of Pt catalyst.The samples were characterized using XRD,SEM,TEM and electrochemical method,respectively.Pt nanoparticle synthesized by CVs shows non-uniform size with equivalent(110)and(100)facets on the surface,while that prepared by wave potential exhibits uniform size and morphology with dominated(100)facet.The comparative study of two kinds of Pt catalyst for nitrate reduction indicates that the reactivity of Pt nanoparticles for nitrate reduction is depended on the fraction of exposure of Pt(100).The process of electrocatalytic nitrate reduction was study in detail and possible mechanism was speculated according to the experimental results.In order to improve the mass transport during nitrate reduction process,the 3D structural carbon fiber paper(CFP)was selected as the substrate for Pt nanoparticleand the influence was studied.The effect of potential range,cycles and residence time on the growth and morphology of electro-deposited Pt nanoparticles was studied,indicating that the morphology of Pt nanoparticles was dominated by potential range.The synthesized CFP supported Pt nanoparticles electrode was applied to study the removal of nitrate by electrocatalytic reduction,showing excellentcatalytic activity.The Pt nanoparticles supported on CFP is expected as a high active electrode for the effective removal of nitrate in groundwater.