Optimization of high surface area VOx/TiO2 catalysts for low-temperature NH3-SCR for NOx abatement

We have prepared two series of VOx/TiO2 catalysts (V surface density in the range 1.6-7.7 V at/nm(2)) employing anatase TiO2 with different surface area (89 and 181 m(2)/g) to find the optimal composition for the low temperature NH3 Selective Catalytic Reduction and correlate their physico-chemical properties to performance. The same platelet-like morphology was observed for the two TiO2 supports by electron microscopies and X-ray diffraction, indicating that the different surface area is only related to particle size. A higher amount of defective surface sites (undercoordinated Ti4+ sites at edges, corner and steps positions) was found on the high surface area TiO2 by FTIR spectroscopy of CO probe molecule. The distribution of VOx species determined by FTIR and Raman spectroscopies is similar on the two series, reaching the monolayer coverage and maximum activity at approximate to 5 V at/nm(2), which can be considered the optimal V density for these catalysts. (c) 2023 Elsevier Inc. All rights reserved.

Automated summary

In this study, two series of VOx/TiO2 catalysts with different surface areas of anatase TiO2 were prepared to find the optimal composition for low temperature NH3 Selective Catalytic Reduction (SCR). The physico-chemical properties of the catalysts were correlated to their performance. It was found that the different surface area of TiO2 supports only affected particle size, while the high surface area TiO2 had a higher amount of defective surface sites. The distribution of VOx species on the two series was similar, with the optimal V density at approximately 5 V at/nm(2).