Electrochemical reduction of carbon dioxide to formate with a Sn cathode and an IrxSnyRuzO2/Ti anode

Abstract

The electrochemical reduction of CO₂ to formate has been studied extensively, and most studies have focused on the faradaic efficiency for producing formate. However, the energy efficiency is also critical for the possible industrialization of the process, as it specifies the energy recovered in the product. Here, we report that the energy efficiency is 35.6% when a Pt electrode is used as the anode, and it can increase to 42.1% when an Ir_xSn_yRu_zO₂/Ti electrode with lower overpotential for oxygen evolution reaction is used as the anode, in spite of their faradaic efficiencies for producing formate are very close (85.1% and 84.8%). When the Ir_xSn_yRu_zO₂/Ti electrode coated with Nafion membrane is used as the anode, the faradaic efficiency can maintain at 79.6% through a long time electrolysis of CO₂ for 500 C.