Electrocatalytic Properties of Tungsten Carbide and Montmorillonite Nanocomposites

The extranuclear electron arrangement of tungsten carbide (WC) possesses the platinum-like catalytic activity due to its similarities with platinum, which can be used as a catalyst in the electrochemical field and has become a hot research topic due to its excellent resistance to H₂S and CO poisoning , but its electrocatalytic activity is far less than platinum and other precious metal catalysts. Therefore, the improvement of activity is the key and the technical problem facing WC substitution or partial replacement of platinum and other precious metal catalysts.

Some scholars choose montmorillonite (MMT) as the carrier of tungsten carbide, preparation of tungsten carbide and montmorillonite composite catalytic material, and study its performance, because MMT has a 2: 1 layered structure, is a natural silicic acid salt-layered structural materials, it has the advantages of strong surface electronegativity, large specific surface area, strong adsorption and good cation exchange performance. It has good dispersing and stabilizing effect on nano-particles and can maintain the stability of the composite catalyst. Therefore, the catalysis of tungsten carbide with the catalytic activity of the platinum like catalyst on the MMT nanoscale layer must be well catalyzed.

The WCl₆ was dissolved in 50 mL of absolute ethanol, and then E-MMT was added to the above solution. The ultrasound was dispersed for 10 min. The system was placed in the 30 °C water bath, stirring at constant temperature for 24 h, then static WO₃/MMT, filtration, washing, drying and grinding were used to obtain WO₃/MMT precursor. The precursor is installed in a quartz boat and placed in a tubular electric furnace. After nitrogen (N₂) 30 min, the mixture of CH₄ and H₂ is modified (the volume ratio of CH₄:H₂ is 1:4). At the same time, the temperature of the tube furnace increased to 400 °C, maintained 30 min, then increased to 800 °C for a period of time, then cooled to room temperature under the protection of N₂, namely tungsten carbide and montmorillonite nanocomposites.

Tungsten carbide and montmorillonite nanocomposites were used for electrocatalytic acid methanol solution. The results showed that tungsten carbide and montmorillonite nanocomposites had good electrocatalytic activity for methanol in acidic system and had platinum like catalysis. The electrocatalytic activity is not only related to the phase composition of composites, but also to the microstructure characteristics of composites. When the phase of tungsten carbide is composed of WC and W₂C, WC is the absolute majority. And both in montmorillonite lamellae formed on the outer surface of the uniform load layer, the best electrocatalytic activity for methanol composite material, and the platinum catalytic properties of the strongest, which shows that the montmorillonite layers is a good carrier of tungsten carbide.

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