Molybdenum-decorated V₂O₅–WO₃/TiO₂: surface engineering toward boosting the acid cycle and redox cycle of NH₃-SCR

Abstract

Submonolayer Mo-decorated V2O5–WO3/TiO2 provides abundant vanadia species and unsaturated V4+ species, accelerating the acid and redox cycling of low-temperature NH3-SCR.

Decrypting Catalytic NOX Activation and Poison Fragmentation Routes Boosted by Mono- and Bi-Dentate Surface SO32–/SO42– Modifiers under a SO2-Containing Flue Gas Stream

“…Notably, one may suggest the use of metal oxide nanocomposites currently being commercialized for the SCR as model catalysts in this study (e.g., V 2 O 5 /TiO 2 , V 2 O 5 –WO 3 /TiO 2 , or V 2 O 5 –MoO 3 /TiO 2 ). These catalysts, however, lack the methodology concerning the alteration of binding configurations for SO A 2– modifiers (i.e., mono -dentate ↔ bi -dentate), suffer from substantial reduction of O α /O V (redox) species upon SO A 2– functionalization, or possess little propensity to bind with SO 2 (AS/ABS deposition ↓), , thereby being hardly exploited to disclose the significance of the kind/binding array for SO A 2– (B – ) species or redox sites in expediting the SCR and AS/ABS fragmentation routes via kinetic assessments. (See Figure S1 for details.)…”

Effect of Catalyst Crystallinity on V-Based Selective Catalytic Reduction with Ammonia

“…V 2p was mainly composed of V 5+ and V 4+ , and the two fitted peaks at 517.1 and 516.1 eV could be attributed to V 5+ 2p 3/2 and V 4+ 2p 3/2 , respectively [35]. According to previous studies, V 4+ can promote the adsorption of oxygen and form reactive oxygen species on the surface of a catalyst, leading to fast redox cycles and improving the redox properties [36]. Figure 5c shows that crystalline V 2 O 5 -WO 3 /TiO 2 contains a higher proportion of V 4+ than amorphous V 2 O 5 -WO 3 /TiO 2 .…”

Promotional effect of Fe and Ce co-doping on a V2O5–WO3/TiO2 catalyst for SCR of NOx with high K and Pb resistance

“…As shown in Fig. 6, the reduction peaks centered at 470 °C and 538 °C 2,30,31 in the VWTi catalyst could be ascribed to the reduction V 5+ → V 4+ → V 3+ in the surface region. The peak centered at 645 °C in the VWTi catalyst was attributed to the reduction of WO x.…”

“…The peak centered at 645 °C in the VWTi catalyst was attributed to the reduction of WO x. 30 Compared with VWTi, the reduction peaks at 460 °C and 572 °C of the CeVWTi catalyst shown in Fig. S6,† could be attributed to the overlapping reduction peaks of nonstoichiometric Ce 4+ and V 5+ in the surface region.…”