High-Pressure Electro-Fenton Driving CH₄ Conversion by O₂ at Room Temperature

Abstract

Electrochemical conversion of CH₄ to easily transportable and value-added liquid fuels is highly attractive for energy-efficient CH₄ utilization, but it is challenging due to the low reactivity and solubility of CH₄ in the electrolyte. Herein, we report a high-pressure electro-Fenton (HPEF) strategy to establish a hetero-homogeneous process for the electrocatalytic conversion of CH₄ by O₂ at room temperature. In combination with elevation of reactant pressure to accelerate reaction kinetics, it delivers an unprecedented HCOOH productivity of 11.5 mmol h^-1 g_Fe^-1 with 220 times enhancement compared to that under ambient pressure. Remarkably, an HCOOH Faradic efficiency of 81.4% can be achieved with an ultralow cathodic overpotential of 0.38 V. The elevated pressure not only promotes the electrocatalytic reduction of O₂ to H₂O₂ but also increases the reaction collision probability between CH₄ and •OH, which is in situ generated from the Fe²⁺-facilitated decomposition of H₂O₂.