Impact of Forced Convection on Spectroscopic Observations of the Electrochemical CO Reduction Reaction

• Published in: ACS catalysis 2020-01, Vol.10 (2), p.941-946
• Main Authors: Malkani, Arnav S, Li, Jing, Anibal, Jacob, Lu, Qi, Xu, Bingjun
• Format: Article
• Language: English
• ISSN: 2155-5435; 2155-5435
• DOI: 10.1021/acscatal.9b03581

The electrochemical CO reduction reaction (CORR) has been shown to suffer from mass transport limitations owing to the low solubility of CO in aqueous electrolytes (∼1 mM). However, no direct observation of the impact of the mass transport on the adsorbed CO coverage on Cu, and in turn the CORR activity, has been reported because of the lack of suitable experimental techniques. In this work, we employ operando surface enhanced infrared absorption spectroscopy with and without stirring to investigate the CO binding sites at potentials relevant to the CORR and correlate with reactivity studies. The significant loss in CO peak intensity observed in the spectra at below −0.6 V without stirring highlights the importance of including forced convection in spectroscopic studies to obtain information representative of typical reaction conditions. Despite roughly 1 order of magnitude lower CO coverage on Cu at −0.7 V without stirring, as compared to the case with stirring, the relative distribution of CORR products does not change appreciably, suggesting that adsorbed CO on Cu exists in patches rather than distributing uniformly.