Enhanced methane chlorination via RuO2-gas convection electrode with in-situ generated dynamical three-phase boundaries

Chloromethane (CH3Cl) is a crucial chemical intermediate conventionally synthesized under harsh conditions. Electrocatalytic methane (CH4) chlorination enables a sustainable alternative by utilizing abundant CH4 and chlor-alkali feedstocks under ambient conditions. However, the high stability and low solubility of CH4 limit CH3Cl’s production. To address these issues, we develop a hierarchical system integrating catalyst and electrode designs. RuO2 catalyst is applied for surface adsorbed chlorine (*Cl) generation and CH4 activation. We also design a gas convection electrode (GCE), achieving a CH3Cl yield of 547.5 ± 33.4 mmol cm-2 h-1 and a 19-fold enhancement in faradaic efficiency compared to gas diffusion electrodes. This enhancement is attributed to efficient *Cl production by RuO2, coupled with the convection-dominated mass transport and the GCE’s in-situ generation of dynamic three-phase boundaries. Here, we demonstrate an efficient catalyst for electrocatalytic CH4 chlorination and propose a broadly applicable strategy to enhance reaction efficiency involving less soluble gaseous reactants. Electrocatalytic methane chlorination offers a greener route to chloromethane. Here, the authors report a RuO2-based gas-convection electrode that enhances CH4 mass transfer, giving higher CH3Cl yield and faradaic efficiency than conventional gas-diffusion electrodes.