Analysis on the effect of operating conditions on electrochemical conversion of carbon dioxide to formic acid

摘要

Electrochemical reduction of CO_2 to HCOOH was performed on a Sn electrode using a proton exchange membrane-embedded electrolysis cell. The effects of reaction conditions such as catholyte and anolyte types, reduction potential, catholyte pH, and reaction temperature on the amount of HCOOH and its faradaic efficiency were investigated. Four different electrolytes (KOH, KHCO_3, KCl, KHSO_4) were chosen as the candidate catholyte and anolyte; the most suitable electrolyte was chosen by monitoring the amount of HCOOH and faradaic efficiency. The effect of the pH of the selected catholyte on the conversion of CO_2 to HCOOH was also investigated. In addition, the reaction temperature was varied and its effect was studied. From the observations made, we determined the optimal reaction conditions for the production of HCOOH via the electrochemical reduction of CO_2 by a systematic approach.