Research on the reaction mechanism of ethanol oxidation reaction (EOR) is important for the development of highly active EOR electro-catalysts.One of the main difficulties in the EOR study is the quantitative analysis of the non-volatile products.Conventional on-line electrochemical flowing transmission infrared spectroscopy (ETIRS) can only collect a part of the carbonate products of EOR in alkaline media,making the further quantitative study impossible.Herein,a new ETIRS system has been designed and prepared by employing a cation-exchange membrane (Nafion) in the sampling hood.The using of the Nafion membrane can prevent the anions crossing over by confining the generated carbonates in the sampling hood without diffusing into the bulk electrolyte.Therefore,the collection efficiency of the carbonate products as well as the test accuracy of the carbonate current efficiency has been sig nificantly improved.The result of CO stripping reaction shows that ca.100％ of the carbonate product is able to be collected in alkaline media by this new system.The influence of the experimental tem perature to the carbonate current efficiency has been further studied on Pt/C toward EOR in alkaline media.