UCLA

The conversion of methane to valuable chemicals via electrochemical approaches is of great interest in the field of catalysis. Conventional catalytic processes utilize extreme conditions (high temperatures or pressures) to provide the energy required to achieve methane activation and require sophisticated heat integration networks to be economically viable. In contrast, catalytic processes via electrification or electrocatalysis offers direct routes of methane activation under ambient conditions, with lower energy requirements and simplified configurations. However, electrochemical oxidation of methane using current electrocatalysts remains challenging due to low energy efficiencies and a seemingly unavoidable trade-off between conversion and selectivity. In this regard, many research efforts have been devoted to the development of efficient and selective electrocatalysts for the activating and transformation of methane into valuable chemicals. Over the last decade, researchers have shown that composite transition metal oxides such as NiO/ZrO2 and Co3O4/ZrO2 can catalyze the electrochemical partial oxidation of methane to value-added chemicals such as methanol, ethanol, and propanol in a carbonate electrolyte. Chemical co-precipitation has been utilized predominantly for the preparation of metal oxide catalysts which involves multiple steps such as centrifugation, collection, drying, and annealing, and result in oxide materials with poor conductivity which are not amenable to electrocatalysis. In this work, a one-step electrodeposition method has been developed for the preparation of CoZrOx electrocatalysts. The electrodeposited CoZrOx material was found to be an active electrocatalyst for the partial oxidation of methane with a simple fabrication method. Furthermore, different electrodeposited unary transition metal oxides (CoOx, NiOx, MnOx, FeOx, and CuOx) were prepared through the same electrodeposition method, and were also studied for the electrochemical oxidation of methane. CoOx, NiOx, CuOx, and the CoZrOx electrocatalysts have been discovered to catalyze the conversion of methane to methanol. The preliminary results in this work demonstrate an additional approach among the available strategies for catalyst fabrication and may provide an efficient strategy of catalyst preparation for further studies of the electrochemical oxidation of methane under ambient conditions.