Development of a low flow vapor phase electrochemical reactor without catholyte reliance for CO2 electrolysis to high value carbon products

TL;DR

This paper presents a stable, catholyte-free vapor-fed electrochemical reactor for CO2 reduction, achieving high efficiency and selectivity with adaptable design suitable for testing various catalysts.

Contribution

The development of a continuous, catholyte-free vapor-fed electrochemical cell with flexible architecture for efficient CO2 reduction and catalyst testing.

Findings

Achieved ~80% FE for CO with Ag catalyst over 12 hours

Demonstrated ~40% FE for ethylene with Cu catalyst

Stable operation for up to 72 hours

Abstract

A continuous CO2 vapor-fed electrochemical cell prototype that performs CO2R with high faradaic efficiency for desired carbon products for up to 72 hours of operation is presented. The cell design facilitates a flow through configuration, capitalizing on gas diffusion electrode (GDE) and membrane electrode architecture (MEA) without requiring a catholyte. We demonstrate stable performance and design adaptability by incorporating various CO2R catalysts and membranes into the cell, investigating lifetime performance and selectivity under established experimental conditions. With an Ag foil and PPO anion exchange membrane, the design achieves an average current density of -30mA/cm2 and FE ~80% for CO obtained over a 12-hour duration. With a Cu-based catalyst, FE ~40% selectivity for ethylene was achieved. The unique geometry and flexibility of the cell provides an adaptive and dynamic GDE electrochemical cell framework, easing future research for novel electro-catalysts on GDE electrodes and MEA/GDE assemblies for enhanced (photo)electrochemical carbon dioxide reduction.