Copper nanoclusters: Selective CO2 to methane conversion beyond 1 A/cm²

Abstract

Carbon dioxide offers a unique opportunity as a feedstock for energy production through electrocatalysis. Methane production holds promise for its widespread applications and market demand. However, commercial viability faces challenges of low selectivity, current density, and high applied potential. Efforts to improve methane selectivity while suppressing multi-carbon products, e.g., ethylene, often involve lower alkalinity electrolytes. However, it reduces current density due to increased ohmic resistance without significant gains in the reaction yield. This study utilizes quantum mechanics computations to design a nano-cluster copper catalyst that redirects the reaction pathway from ethylene towards methane, even under alkaline conditions. We achieved a Faradaic efficiency (FE) of 85 %, a current density of 1.5 A/cm2, and stability of over 10 hours solely by controlling particle size in copper catalysts. This work paves the way to overcoming current limitations in electrocatalytic methane production and holds broader implications for advancing sustainable CO2 utilization in energy systems.