Nitrogen oxides is one of the main air pollutants, the large amount of NOx emitted into the air will not only cause a serious threat to the global environment, but also have an adverse effect on human health. The core of the current widespread use of SCR denitration technology is the catalyst, which the main active component is vanadium pentoxide; tungsten trioxide itself also has a denitration capability, besides it plays an important role in anti-toxic, anti-sintering, furthermore, it increases the ability of anti-oxidation of sulfur dioxide; titanium dioxide has a good sulfur resistance and stability, and join improving of the catalyst activity with the active ingredient.

 

Existing experimental result has shown that the particle size of titanium dioxide plays an important influence on the properties of catalyst, mainly performance as bellow:

1. The nanometer catalyst allows a higher airspeed range and wider denitration temperature window than industrial catalysts;

2. When the ratio of ammonia and nitrogen is 1.2, the denitration efficiency of nanometer catalyst can even reach to 100%, significantly higher than the industrial catalyst (at 400°C, maximum 85%), which shows the activity of nanometer-catalyst is higher than that of industrial grade;

3. Nanometer titanium dioxide appears in a white loose powder, while the industrial shows fine particulate; according to reliable calculations, the surface area and pore volume of nanometer titanium dioxide are far greater than the industrial. Therefore, nanometer titanium dioxide can load more active components like tungsten trioxide, vanadium pentoxide, moreover, the active components can uniform load to the internal of carrier, and the acidity after loaded of catalyst surface is significantly higher than that of industrial catalyst; as we know that in the SCR system, the stronger acidic, the more favorable to the adsorption and activation on the catalyst surface, finally, the better denitration activity it has.