Investigation of Electrocatalysts for Selective Reduction of CO2 to CO: Monitoring the Reaction Products by on line Mass Spectrometry and Gas Chromatography

Author(s)

Mariana R. Camilo ^[1] ; Wanderson O. Silva ^[2] ; Fabio H. B. Lima ^[3]

Affiliation

^[1] Universidade de São Paulo. Instituto de Química de São Carlos - Brasil

^[2] Universidade de São Paulo. Instituto de Química de São Carlos - Brasil

^[3] Universidade de São Paulo. Instituto de Química de São Carlos - Brasil

• Document type: Journal article
• Source: Journal of the Brazilian Chemical Society; v. 28, n. 9, p. 1803-1815, 2017-09-00.

Abstract

The carbon dioxide electrocatalytic reduction is central for the development of regenerative cycles of electrochemical energy conversion and storage. Herein, the gaseous products of the CO2 electroreduction were monitored by using an electrochemical cell on line coupled to a differential electrochemical mass spectrometer (DEMS), aiming at searching for electrocatalysts with high selectivity for CO formation. The results showed that, among the studied materials, the Cu4Sn/C alloy nanoparticles were stable during potentiostatic polarizations as revealed by in situ X-ray absorption spectroscopy (XAS), and the on line DEMS measurements showed the production of CO, suppression of methane and ethylene formations, and diminishing of the hydrogen evolution reaction, in relation to that on pure Cu2O-Cu/C. The faradaic efficiencies for CO formation were 13 and 23% for Cu4Sn/C and Au/C (a known electrocatalyst for CO), respectively, determined by experiments of in line gas chromatography (GC). The selectivity of Cu4Sn/C for CO formation was ascribed to the role of Sn atoms on stabilizing adsorbed HCOO intermediates, and hindering further hydrogenation, letting CO free for desorption. These results are expected to be used as a guide for further development of electrocatalysts with a fine-tuning of composition for increasing the faradaic efficiency of CO2 electroreduction to CO. (AU)

• FAPESP's process: 13/16930-7 - Electrocatalysis V: electrocatalytic processes of chemical and electrical energy interconversion
• Grantee: Edson Antonio Ticianelli
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 14/26699-3 - Development of electrocatalysts for the electroreduction of CO2 and photo-electrooxidation of water: investigation of the reaction products by on-line mass spectrometry
• Grantee: Mariana Romano Camilo Casale
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/13323-0 - Carbon Dioxide and Water Electrochemistry: Application in Energy Conversion and Storage
• Grantee: Fabio Henrique Barros de Lima
• Support Opportunities: Regular Research Grants