Chrysanthemum‐Flowers‐Like Bimetal Oxide Based Electrocatalyst for Methanol Oxidation Reaction
Nabi Ullah, Dariusz Guziejewski, Kamila Koszelska, Sylwia Smarzewska, Magdalena Małecka, Katarzyna Ranoszek‐Soliwoda, Jarosław Grobelny
Abstract
Transition metal oxides have garnered attention for the methanol electro‐oxidation reaction owing to their easy availability, high catalytic applicability, and multiple oxidation capabilities. Bimetal‐based catalysts further enhance the performance of the methanol oxidation reaction. In this context, a chrysanthemum‐flower‐like MoO 2 /WO 3 is synthesized through a solvothermal and annealing strategy. The morphology attests to the rough surface and pores in the catalyst, augmenting its surface area for reactions and enhancing catalytic applicability. Electrochemical oxidation of methanol yields an optimal current density of 0.99 mA cm −2 and 2.07 mA mg −1 at a potential of 0.57 V versus Ag/AgCl. The catalyst exhibits a remarkably low Tafel slope of 37.45 mV dec −1 , affirming its rapid reaction kinetics. Electrochemical impedance spectroscopy (EIS) reveals an equivalent electronic circuit of R ( Q ( R (QR) Q (RW))), confirming low charge transfer resistance ( R ct ) and diffusion‐controlled kinetics attributable to the pores in the sample. The sample also demonstrates an electrochemically active surface area (ECSA) value equal to 0.122 mF cm −2 and long‐term stability over continuous 5000 s, exhibiting no change and high resistance to CO poisoning. All these characterizations and obtained results collectively affirm that the chrysanthemum‐flower‐like MoO 2 /WO 3 serves as a highly suitable electrocatalyst for the electrochemical oxidation of methanol.