Study on the local difference of monolithic honeycomb V2O5-WO3/TiO2 denitration catalyst

For some commercial monolithic honeycomb V2O5-WO3/TiO2 SCR denitration catalysts, an unusual gray cylindrical region is observed through the axle center of each catalyst. There is plain local difference in color, mechanical strength and activity between samples from normal area and gray area in one catalyst. A series of microscopic characterizations including X-ray photoelectron spectroscopy and in situ diffuse reflectance infrared Fourier transform spectroscopy are conducted to find the factors affecting the local difference and the correlation between performance difference and microscopic physicochemical property of V2O5-WO3/TiO2 catalyst. The results show that the different V oxidation states and W chemical states between two samples result in the color variation. The catalyst sample from gray area possesses higher mechanical strength but lower activity, which results from the higher crystallinity, larger mesopore diameter, less chemisorbed oxygen, lower amount of active component and weaker acid sites. This work offers reference to further optimization of preparing and testing of SCR denitrification catalyst for manufacturers and testing institutes.