Highly efficient formic acid and carbon dioxide electro-reduction to alcohols on indium oxide electrodes. Issue 8 (9th June 2020)

• Record Type: Journal Article
• Authors: Adegoke, Kayode Adesina; Radhakrishnan, Shankara Gayathri; Gray, Clarissa L.; Sowa, Barbara; Morais, Claudia; Rayess, Paul; Rohwer, Egmont R.; Comminges, Clément; Kokoh, K. Boniface; Roduner, Emil
• Is Part Of: Sustainable energy & fuels. Volume 4:Issue 8(2020)
• Page Start: 4030
• Page End: 4038
• Publication Date: 2020-06-09
• Subjects: Renewable energy sources -- Periodicals; Fuel cells -- Periodicals; Electric batteries -- Periodicals; Electrochemistry -- Periodicals; 660.297
• DOI: 10.1039/d0se00623h
• Languages: English
• ISSNs: 2398-4902

Abstract

Abstract : Co-electrolysis of formic acid and water using an indium oxide cathode catalyst yields a mixture of methanol, ethanol and iso-propanol with a Faraday efficiency up to 82.4%. The reaction of aqueous carbon dioxide occurs via a competing pathway. Abstract : Formic acid is often assumed to be the first intermediate of carbon dioxide reduction to alcohols or hydrocarbons. Here we use co-electrolysis of water and aqueous formic acid in a PEM electrolysis cell with Nafion® as a polymer electrolyte, a standard TaC-supported IrO2 water-splitting catalyst at the anode, and nanosize In2 O3 with a small amount of added polytetrafluoroethylene (PTFE) as the cathode. This results in a mixture of methanol, ethanol and iso-propanol with a maximum combined Faraday efficiency of 82.5%. In the absence of diffusion limitation, a current density up to 70 mA cm −2 is reached, and the space-time-yield compares well with results from heterogeneous In2 O3 catalysis. Reduction works more efficiently with dissolved CO2 than with formic acid, but the product distribution is different, suggesting that CO2 reduction occurs primarily via a competing pathway that bypasses formic acid as an intermediate.