ORR Catalyzed by Transition Metal Carbide

Transition metal carbide, in particular tungsten carbide, is another type of nonnoble catalyst showing activity towards the oxygen reduction reaction. However, the main catalytic activity of carbide is not in the oxygen reduction reaction, but rather in other reactions such as H2 oxidation. Mazza et al. [73] reported that WC, TaC, Tie, and TiN showed catalytic activity towards ORR in acid solutions. However, these materials are not stable in alkaline solution. For example, even in acid solutions, WC did not show long-term stability in the presence of O2 [73]. Lee et al. [74] found that the addition of Ta to WC could significantly improve its catalytic activity and stability. 

The mechanism of flie ORR activity enhancement induced by adding W2C to Pt is not yet clear. Experimental results show that most possibly this is due to the synergistic effect between tungsten carbide nanoparticles and Pt at the interface. 

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