Preparation And Electrocatalytic Activity Of Tungsten Carbide Composite

Tungsten carbide bears an analogy of the catalytic capability of noble metal, e.g. Pt, and higher ability to resist very strong catalytic poisons while its price is low, so it has the possibility to replace noble metal in the industry. The only problem is tungsten’s catalytic activity is much lower compared to that of noble metal, but its catalytic activity could be greatly enhanced by preparing tungsten composite. In order to improve the catalytic activity of tungsten carbide, APT/FeOOH carrier is prepared by surface coating approach while using ammonia metatungsten (AMT) as tungsten source and iron oxide hydroxide (FeOOH) as support. After that, APT/FeOOH carrier is converted into series tungsten carbide composites a,b and c by different processes.Serie a is got by in-situ reduction-carbonization after the support of the carrier is removed and its main phase are WC and W2C with a partical microstructure, which indicates it’s WC/W2C composite. Series b is got by in-situ reduction-carbonization after the carrier is calcined and the support is removed. Its main phase are WC and W2C and the partical shows core-shell structure, under 100 nm, while WC forms the core and W2C forms the shell. This indicates series b is W2C/WC nano-composite. Series c is got by in-situ reduction-carbonization of the carrier. Its main phase is Fe3W3C, and also a small amount of WC, W2C, Fe and else. It also shows core-shell structure with Fe3W3C forms the core and others form the shell. This indicates series c is WC/Fe3W3C composite.The electrocatalytic activities for PNP of a,b and c are studied and the results show series b peforms the best activity, while series c peforms the worst activity and series a is in the between. This is because WC and W2C both possess good catalytic activity for PNP and core-shell structure of series b enhanced the synergistic effect of WC and W2C. Series c showed the worst activity is because its main phase Fe3W3C doesn’t possess good catalytic activity for PNP.The electrocatalytic activities for CH3OH of a,b and c are studied and the results show series b peforms the best activity, while series a peforms the worst activity and series c is in the between. What makes the difference is W2C showed much worse activity for CH3OH than WC and Fe3W3C and Fe in series c possess good catalytic activities for CH3OH.The paper also compared the electrocatalytic activities of series a,b,c and mesoWC and partWC. The results indicate the electrocatalytic activities of series a,b,c are enhanced based on the partWC and the activity of series b is even better than mesoWC in both PNP and CH3OH systems.Based on the above results, one conclusion can be drawn that tungsten carbide composite with high catalytic activity can be prepared by load the AMT on the surface of FeOOH, and this is one of the efficacious ways to improve its electrocatalytic activity.