Tungsten trioxide is an n-type semiconductor function material, because the variety of variable valence, excellent cation exchange, molecular adsorption, redox and electromagnetic, it is widely used in various catalytic oxidation reaction, separation, electrochemistry, photocatalysis and other fields. Except for the hydrofluoric acid, WO₃ can insoluble in any other acids, and can fully adapt to working environment and stay stable of the fuel cell high pressure and humidity and low pH value. In addition, the WO6 octahedral structure of WO₃ can form complex network, and can accommodate a variety of different cations or water molecules, forming the crystal structure of one-dimensional, two-dimensional layered and three-dimensional network.

 

Tungsten oxide surface has excellent hydrophilicity, and can easily be partially reduced to form mixed oxide of valence +5 and +6 which containing hydroxyl on surface, thus bring out the surface oxygen vacancies and hydroxyl groups generated by hydrolysis will both improve the surface oxidation of electrons with the adsorbed species, which increases the rate of electron mobility of the interface between the tungsten trioxide and Pt. So that, the harmful substances of SO_x adsorbed on the surface of the catalyst will be accelerating oxidized and to desorption from the surface of the catalyst to reduce the impact of the SO_x poisoning, and moreover to promote the recovery of the fuel cell performance. In addition, WO₃ can accept the active hydrogen ion which transferred from platinum catalyst, and combined to form a tungsten bronze, thus to re-release the active area of platinum for the adsorption of other hydrogen, thereby significantly improving the efficiency of the catalytic platinum catalyst. In addition, WO₃ as catalyst carrier can directly significantly improve the formic acid fuel cell performance. Optimal mass ratio of WO₃-Pt / C catalyst not only can make the poisoning influence of sulfur dioxide reached the lowest, and the recovery rates reach to the maximum, but also it can get better catalysis and stability.