Integration of binary Ta2O5 nanoparticles on ternary MnWO4 nanorods as novel electrocatalysts with enhanced activity toward methanol oxidation reaction

초록

The adherence of Ta2O5 nanoparticles to MnWO4 nanorods forms a composite structure of MnWO4@Ta2O5 that has been utilized as a high-performance electrocatalyst for the methanol oxidation reaction (MOR). The resulting composite structure has several advantages, such as a synergistic effect, flower-like morphology with numerous active sites, improved surface area, and high electron conductivity toward the MOR. Herein, a simple hydrothermal method synthesizes four MnWO4@Ta2O5 electrocatalysts, denoted as TMW-1, TMW-2, TMW-3, and TMW-4, respectively, with respective Ta2O5 concentrations of 25, 50, 75, and 100 mg. Several techniques are used to characterize the crystalline structure, size, morphology, functional groups, and elemental composition of the electrocatalysts. To study the performance of the materials toward methanol oxidation, cyclic voltammetry (CV), chronoamperometry (CA), electrochemical active surface area analysis (ECSA), and electrochemical impedance spectroscopy (EIS) are used to understand the electrocatalytic activity, selectivity, and stability of the material in comparison it with the pure Ta2O5. Among all the samples, TMW-3, which is prepared with 75 mg of Ta2O5, exhibits a performance that is three times better than pure Ta2O5 toward MOR by providing an anodic current density of 159 mA g−1 at 0.70 V (vs. Hg/HgO) at a scan rate of 100 mV s−1. The enhanced electrochemical activity is attributed to the desired concentration of Ta2O5 in MnWO4 and its high surface area of 67 mF cm−2.

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