Activity Descriptors for CO₂ Electroreduction to Methane on Transition-Metal Catalysts

TLDR

The electrochemical reduction of CO₂ into hydrocarbons and alcohols offers a route to convert renewable energy into fuels and chemicals, yet no electrode catalysts have been developed that achieve this transformation with low overpotential at reasonable current densities. The study compares trends in binding energies of CO₂ reduction intermediates and presents an activity volcano to guide catalyst design. The authors propose new strategies for discovering catalysts capable of operating at reduced overpotential. The analysis explains the experimentally observed variations among transition‑metal catalysts, identifies copper as the best-known electrocatalyst, and highlights that protonation of adsorbed CO is the key step determining overpotential.

Abstract

The electrochemical reduction of CO2 into hydrocarbons and alcohols would allow renewable energy sources to be converted into fuels and chemicals. However, no electrode catalysts have been developed that can perform this transformation with a low overpotential at reasonable current densities. In this work, we compare trends in binding energies for the intermediates in CO2 electrochemical reduction and present an activity “volcano” based on this analysis. This analysis describes the experimentally observed variations in transition-metal catalysts, including why copper is the best-known metal electrocatalyst. The protonation of adsorbed CO is singled out as the most important step dictating the overpotential. New strategies are presented for the discovery of catalysts that can operate with a reduced overpotential.