# Oxygen Evolution Reaction Catalysts for Acidic‐Media CO2 Electrolyzers

## TL;DR

This review explores catalysts for acidic CO2 electrolyzers, aiming to improve efficiency and reduce reliance on rare noble metals.

## Contribution

The paper provides a roadmap for developing durable and economically viable acidic CO2 electrolyzers by integrating catalyst design and system-level insights.

## Key findings

- Noble and non-noble metal catalysts can be engineered for better activity and stability in acidic CO2 electrolysis.
- Diagnostic and computational methods link atomic-level properties to macroscopic durability in OER catalysts.
- Lessons from water electrolysis can accelerate the development of CO2R systems.

## Abstract

Acidic‐media electrochemical CO2 reduction (CO2R) offers high single‐pass CO2 conversion (SPCE) and low purification cost, yet relies on scarce noble metals (e.g., iridium and ruthenium) for the anodic oxygen evolution reaction (OER). The limited abundance of these catalysts constrains large‐scale deployment. Drawing lessons from proton‐exchange membrane water electrolysis (PEMWE), this review integrates recent progress in acidic‐media OER catalysis with system‐level CO2R. It provides a cross‐scale perspective from mechanistic understanding and theoretical modeling to electrode architecture and operational optimization, highlighting how noble‐ and non‐noble‐metal catalysts can be engineered for enhanced activity, stability, and resource efficiency. The review further outlines diagnostic and computational approaches that connect atomic‐level descriptors with macroscopic durability. By bridging mechanistic insights and scalable system design, this work establishes a roadmap toward durable and economically viable acidic‐media CO2 electrolyzers.

Acidic‐media CO2 electroreduction (CO2R) could decarbonize chemical production, despite relying on rare‐earth elements for anodic oxygen evolution reaction (OER). Transferring the learnings from mature sister technologies (water electrolysis) could accelerate technological development. This article, by focusing on acidic‐media OER for CO2R systems, overviews best practices for performance/stability assessment and progress in catalysts, catalysts characterization, and mechanistic approaches, providing a roadmap to practicality.