V2O5-WO3/Tio2 Catalyst for NO Reduction Using APT

Fossil fuels as the major energy source had contributed to the rapid development of human society. At the same time, the green house gases such as CO2 and NH4 had brought the global warning, climate change, and many other issues. Combustion of most fuels, such as coal, oil, natural gas and biomass etc, results in emission of NOx, which is harmful to our environment creating acid rain and photochemical smog.

The most conventional NOx reduction is selective catalytic reduction (SCR) with ammonia injection into the flue gas. Furthermore, the most used SCR catylst is V2O5-WO3/TiO2 catalyst, as the portion of vanadium oxide is commonly less than 1 wt%. In order to enhance the NO reduction efficiency, a V2O5-WO3/TiO2 catalyst (3 wt%  V2O5 and 5 wt% WO3) had been synthesized using ammonium paratungstate (APT) as raw material.

The experimental method for synthesizing V2O5-WO3/TiO2 catalyst using APT is as below:

Calculated quantity of ammonium paratungstate (APT) and ammonium metavanadate were mixed in the oxalic acidsolution in the desired proportions, and commercial TiO2 (P25) was used as the support to obtain a slurry. The slurry was then stirred in an ultrasonic vibrator for 6 h, dried at 110 °C for 12 h and calcined at 500 °C for 5 h in air. The fresh catalysts, denoted as xV, where x is the weight percent of vanadia, were then grinded and sieved to particles of 0.45–0.3 mm. K+-poisoned catalysts were prepared by impregnating fresh catalysts into KNO3 solution, and then stirred at room temperature for 6 h, dried at 110 °C for 12 h and calcined at 500 °C for 5 h in air.

In conclusion, V2O5-WO3/TiO2 catalyst (3 wt%  V2O5 and 5 wt% WO3) had been synthesized using ammonium paratungstate (APT) as raw material. The BET surface area of the catalysts is 74.4 m²/g and pore size of 13.09 nm. Catalysts with 3 wt% V2O5 are preferable for flue gases with high alkali metal contents. Excellent performance for NO reduction had been observed.

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