Recent years, with the vehicle fleet constantly increasing, the pollution of harmful emissions from motor vehicles, such as NOx and particulates has become increasingly prominent. SCR is the most mature and widely used denitration technology, which is mainly vanadium system, its main active substance is vanadium pentoxide, and titanium dioxide as the carrier; for increasing its anti-sulfur poisoning, you can add tungsten trioxide to this catalyst, thereby improving the denitration performance. Traditional vanadium SCR denitration catalyst has the high and narrow range (300~450°C) of activation temperature, thus limiting its use in diesel engines.

 

Studies have found that the introduction of some metals (such as Ni, Fe, Cu and Zr, etc.) will enhance the low-temperature activity of tungsten trioxide diesel engines denitration catalyst. Among them, in particular, the catalyst incorporated Zr has the best low-temperature activity with highest temperature window. Experiments showed that, after the Zr loaded, tungsten trioxide denitration catalyst had the denitration efficiency of 95% under relatively low temperatures (180°C), which shows that the addition of Zr help to improve the denitration performance at low temperatures, prompting load synergy between the metal oxide catalyst. In addition, with the increasing of Zr, the denitration catalyst performance better within the appropriate range.

 

Zirconia has the acidic, alkaline, oxidizing and reducing, widely used as a co-catalyst and crystal transformation inhibitors. When the Traditional vanadium-tungsten-titanium denitration catalyst loaded 3% of vanadium, and 6% of tungsten, it shows the best activity under the high temperature of 350°C, and the 93%conversion rate of NOx. However, after doped zirconia, it exhibits a highly efficient and stable denitration activity under the flue gas temperature among 200~350℃, with the optimum activity temperature point of 300℃, and 96% of conversion rate of NOx.