Unique nano-granular ZnCo₂O₄ microplate-decorated Pt/C as an efficient electrocatalyst for methanol electrooxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts is crucial for direct methanol fuel cells (DMFCs).
• Platinum supported on carbon (Pt/C) is a common catalyst but suffers from CO poisoning and limited durability.
• Novel catalytic scaffolds are needed to enhance Pt/C performance and stability.

Purpose of the Study:

• To synthesize nanogranule-assembled hierarchical ZnCo2O4 microplates as a catalytic scaffold.
• To couple ZnCo2O4 with Pt/C to form a Pt/ZnCo2O4/C nanocomposite.
• To evaluate the electrocatalytic performance of the developed nanocomposite for methanol electrooxidation.

Main Methods:

• One-step hydrothermal synthesis of ZnCo2O4 microplates.
• Reflux method for coupling ZnCo2O4 with Pt/C.
• Physicochemical characterization (HRTEM, etc.).
• Electrochemical evaluations (cyclic voltammetry, CO-stripping, chronoamperometry).

Main Results:

• ZnCo2O4 microplates exhibit high phase purity, porosity, and uniform Pt nanoparticle anchoring.
• Pt/ZnCo2O4/C shows a higher electrochemically active surface area (30 cm2 mg-1) than Pt/C (17 cm2 mg-1).
• The nanocomposite demonstrates a five-fold mass activity (110 mA mgPt-1), enhanced CO tolerance, and improved stability over 500 CV cycles and 2-hour amperometric studies.
• ZnCo2O4 facilitates OHads species adsorption for poisoning species removal.

Conclusions:

• Nanostructured ZnCo2O4 microplates effectively enhance the electrocatalytic performance of Pt/C for methanol electrooxidation.
• The porous structure and anchoring sites of ZnCo2O4 contribute to superior activity, antipoisoning capability, and durability.
• This approach offers a scalable strategy for developing advanced electrocatalysts for DMFCs.