Electrochemically Controlled Nucleation of Single CO2 Nanobubbles via Formate Oxidation at Pt Nanoelectrodes

Hang Ren; Martin A Edwards; Yufei Wang; Henry S White

doi:10.1021/acs.jpclett.9b03898

Electrochemically Controlled Nucleation of Single CO₂ Nanobubbles via Formate Oxidation at Pt Nanoelectrodes

J Phys Chem Lett. 2020 Feb 20;11(4):1291-1296. doi: 10.1021/acs.jpclett.9b03898. Epub 2020 Feb 3.

Authors

Hang Ren^{1

2}, Martin A Edwards², Yufei Wang¹, Henry S White²

Affiliations

¹ Department of Chemistry and Biochemistry , Miami University , Oxford , Ohio 45056 , United States.
² Department of Chemistry , University of Utah , Salt Lake City , Utah 84112 , United States.

PMID: 31977230
DOI: 10.1021/acs.jpclett.9b03898

Abstract

CO₂ is an anodic product of many liquid fuel cells. The nucleation of CO₂ nanobubbles during cell operation may block the transport of the fuel to the anode, lowering the overall conversion efficiency. Herein, we report the controlled formation of individual CO₂ nanobubbles at Pt nanoelectrodes via the electrooxidation of formate. The electrochemical data are used to extract key parameters of CO₂ gas nucleation. We determine that CO₂ bubbles nucleate when the concentration of CO₂ at the Pt electrode is greater than ∼0.6 M, corresponding to supersaturation of ∼18. The critical nucleus required for the formation of a CO₂ bubble is measured to have a radius of curvature of ∼100 nm, a contact angle of 173°, and contains ∼70 CO₂ molecules.