Highly Stable NiCoZn Ternary Mixed-Metal-Oxide Nanorods as a Low-Cost, Non-Noble Electrocatalyst for Methanol Electro-Oxidation in Alkaline Medium

There is an imperative necessity to develop low-cost and efficient nanocatalysts as a substitute for expensive and rare noble-metal catalysts such as platinum (Pt) and gold (Au) in overcoming the limitations of carbon monoxide and intermediate poisoning in direct methanol fuel cells (DMFCs). Herein, we report a simple, one-step hydrothermal synthesis of NiCoZn ternary mixed-metal-oxide nanorod (NCZMMO)-modified glassy carbon electrode (NCZMMO/GCE) for DMFC application. The NCZMMO/GCE electrode exhibits outstanding electro-oxidation of methanol (MeOH) at a low onset potential of 0.30 V (vs Ag|AgCl) with a high current density of 414 mA/mg in an alkaline medium (1 M KOH). This outstanding performance of the electrode is ascribed to the synergistic outcome of NCZMMO nanorods, where Ni imparts the electrocatalytic active sites for methanol oxidation reaction (MOR) through its multiple oxidation states while the excellent mechanical and chemical stability of the electrode is attributed to the oxides of Co and Zn. The electrode exhibits outstanding durability with 75% retention even at 5000 s of chronoamperometry analysis in the presence of 0.5 M MeOH, which is far superior to other reported noble-metal electrocatalysts. This superior performance of NCZMMO frontlines it as a promising non-noble, low-cost electrocatalyst for various energy conversion applications.