Promoter rather than inhibitor: phosphorous incorporation accelerates the activity of V2O5-WO3/TiO2 catalyst for selective catalytic reduction of NOx by NH3

The selective catalytic reduction of NOx by NH3 (NH3-SCR) over V2O5-WO3/TiO2 catalyst is the state-of-the-art technology for NOx removal from both stationary and mobile sources. Phosphorous can be presented in the fuel gas or as a pelletizing addi-tive to increase the mechanical strength of industrial extruded monolithic V2O5-WO3/TiO2 catalyst. Herein, we demonstrated that a 2-fold increase in the intrinsic activity without detriments to N2 selectivity and anti-H2O/SO2 stability can be achieved by incorporating V2O5-WO3/TiO2 with certain amount of phosphorus, which was generally considered as an inhibitor for such type of catalysts. Phosphorous incorporation enhanced both Bronsted and Lewis acid sites on V2O5-WO3/TiO2, and NH3 bound to both sites are involved in the SCR reaction but with different rates. The molecular structure of surface vanadyl spe-cies was modulated to be more polymeric (dimer and oligomer content increases from 77% to 90%) by phosphorous incor-poration through a spatial effect, during...