Electrocatalytic Coupling Conversion of Methane by Dual-Site Control in Nickel Oxyhydroxide

Methane (CH₄), as both a carbon resource and greenhouse gas, requires an effective and ecologically friendly catalysis to accomplish the conversion into valued-added chemicals or fuels, wherein the establishment of a proper multi-site active structure to boost the C─H dissociation and C─C coupling demands further exploration. Herein, we disclose a facile and general approach by controlling the electronic property of Ni to preserve a moderate orbital hybridization (d-p) with O, and thereby induce a synergistic Ni─O dual-site for the expected electrocatalysis of CH₄ toward C₂ product. Specifically, along the d band shifting downwards via the Ni valence increase, the optimal NiOOH not only affords sufficient capability for the CH₄ oxygenation relative to the Ni(OH)₂, but also minimizes the probability of O detachment compared with the NiO₂. The resultant NiOOH catalyst exhibits the highest Faradaic efficiency of 53.5% with a production rate of 401.6 µmol g_cat. ^-1 h^-1 or 1.61 µmol h^‒1 cm^‒2 for acetic acid, and a long-term stability for over 50 h without detectable structural deterioration. This study develops an efficient electrocatalytic CH₄ process, and could arouse extensive attention to the new materials and routes meeting the economicity and sustainability.