Liquid-Solid Boundaries Dominate Activity of CO&lt;sub&gt;2&lt;/sub&gt;Reduction on Gas-Diffusion Electrodes

Nesbitt, Nathan T.; Burdyny, T.E.; Salvatore, Danielle; Bohra, D.; Kas, Recep; Smith, W.A.

doi:10.1021/acscatal.0c03319

Liquid-Solid Boundaries Dominate Activity of CO₂Reduction on Gas-Diffusion Electrodes

Title

Liquid-Solid Boundaries Dominate Activity of CO₂Reduction on Gas-Diffusion Electrodes

Author

Nesbitt, Nathan T. (National Renewable Energy Laboratory)
Burdyny, T.E. (TU Delft ChemE/Materials for Energy Conversion and Storage)
Salvatore, Danielle (University of Colorado)
Bohra, D. (TU Delft ChemE/Materials for Energy Conversion and Storage)
Kas, Recep (National Renewable Energy Laboratory; University of Colorado)
Smith, W.A. (TU Delft ChemE/Materials for Energy Conversion and Storage; National Renewable Energy Laboratory; University of Colorado)

Date

2020

Abstract

Electrochemical CO2 electrolysis to produce hydrocarbon fuels or material feedstocks offers a renewable alternative to fossilized carbon sources. Gas-diffusion electrodes (GDEs), composed of solid electrocatalysts on porous supports positioned near the interface of a conducting electrolyte and CO2 gas, have been able to demonstrate the substantial current densities needed for future commercialization. These higher reaction rates have often been ascribed to the presence of a three-phase interface, where solid, liquid, and gas provide electrons, water, and CO2, respectively. Conversely, mechanistic work on electrochemical reactions implicates a fully two-phase reaction interface, where gas molecules reach the electrocatalyst's surface by dissolution and diffusion through the electrolyte. Because the discrepancy between an atomistic three-phase versus two-phase reaction has substantial implications for the design of catalysts, gas-diffusion layers, and cell architectures, the nuances of nomenclatures and governing phenomena surrounding the three-phase-region require clarification. Here we outline the macro, micro, and atomistic phenomena occurring within a gas-diffusion electrode to provide a focused discussion on the architecture of the often-discussed three-phase region for CO2 electrolysis. From this information, we comment on the outlook for the broader CO2 electroreduction GDE cell architecture.

Subject

COelectrolysis
COreduction
double-phase boundary
gas-diffusion electrode
triple-phase boundary

To reference this document use:

http://resolver.tudelft.nl/uuid:fd2a8e11-0937-4191-86fe-1d2d4f60eac5

DOI

https://doi.org/10.1021/acscatal.0c03319

Embargo date

2021-11-18

ISSN

2155-5435

Source

ACS Catalysis, 10 (23), 14093-14106