On-line mass spectrometry investigation of the reduction of carbon dioxide in acidic media on polycrystalline Pt

Differential electrochemical mass spectrometry (DEMS) is used to investigate the reaction of electroreduction of CO2 on platinum porous electrode in acidic media. This technique, which gives molecular specificity, permits the reaction products to be followed concurrently with potential and time. These results showed for the first time the on-line production of methanol in acidic media using a Pt electrodeposited electrode. Reduction of CO2 in perchloric acid on Pt occurs in the H2 evolution region leading to the formation of formic acid methanol and traces of methane. Experiments using CO show that this substance is the intermediate of the pathway leading to methanol.