Highly Efficient Methane Electrosynthesis Enabled by Precise, Multifaceted Interface Regulation.

Abstract

The electrocatalytic reduction of carbon dioxide (CO₂) offers a pathway to transform greenhouse gas emissions into fuels and chemicals using renewable electricity. Among possible products, methane (CH₄) is particularly attractive due to its high energy density and seamless integration with existing natural gas infrastructure, yet its electrosynthesis is hindered by demanding multi-electron kinetics and mass-transport constraints. Here, we report a four-channel copper tubular penetration electrode (TPE) with a honeycomb-like architecture that fundamentally reshapes the reaction environment for CO₂ electroreduction. By precisely controlling electrode cross-sectional thickness, this multi-channel design regulates gas, electron, and electrolyte transport, stabilizing the three-phase interface required for efficient CH₄ formation. The optimized TPE achieves a CH₄ Faradaic efficiency of 87.5%, a half-cell energy efficiency of 43.46%, and stable operation for 100 hours. Combined experimental and theoretical analyses reveal that rational design of electrode architecture enables precise control over the CO₂ adsorption configurations and reaction intermediates, thereby fine-tuning the reaction pathway toward CH₄. These findings establish multi-channel TPEs as a powerful platform for efficient CO₂ electromethanation.