Uncovering the centrality of mono-dentate SO32-/SO42- modifiers grafted on a metal vanadate in accelerating wet NOX reduction and poison pyrolysis

Unveiling the Catalytic Merits of LaV3O9 over Conventional LaVO4 Polymorphs to Boost Desired Kinetics of Humid NOX Reduction and Poison Disintegration

“…This was in partial agreement with the N La3+-O2--V5+ values of LaVO 4 /LaV 3 O 9 terminated on the surface (101) facets (Figure S1), where smaller N La3+-O2--V5+ values could limit e − migration from La 3+ to V 5+ , thus rendering V 5+ and neighboring SO Z 2− more e − -deficient and less NH 3 -philic, respectively, in the order of tetragonal LaVO 4 < monoclinic LaVO 4 < LaV 3 O 9 , as speculated above (E NH3 ∼ E BA ↓ for LaV 3 O 9 ). 4,[8][9][10][11]33 Moreover, the XP spectra of the catalysts in the La 3d regions were curve-fitted to four sub-bands, two of which were situated in the La 3d 5/2 domains. These two sub-bands could be assigned to La 3+ and satellite, with their binding energies being ∼16.7 eV smaller than those of the corresponding subbands located in the La 3d 3/2 regimes due to spin−orbit splitting, as reported elsewhere (Figure S6 and Table S3).…”

“…10,15,16 In addition, the characteristics of −OH are arduous to regulate and are occasionally misleading owing to the H 2 O chemisorbed on or near TM n+ -O − /V 4+ , thus motivating the exploration of BA − -H + stemming from SO Z 2− as a substitute for −OH. 10,17,18 Significantly, NH 3 is adsorbed on BA − -H + and generates BA − -NH 4 + , to which TM n+ -O − (O L =TM n+ ; − O L -TM (n−1)+ ) is bound to yield BA − -NH 4 + ••• − O L -TM (n−1)+ . 4,5,9−11 BA − -NH 4 + ••• − O L -TM (n−1)+ then reacts with gaseous NO to produce N 2 and H 2 O in tandem with the evolution of BA − -H + /HO L -TM (n−1)+ .…”

“…Initially, BA − -NH 4 + interacts with NO-− O L -M (n−1)+ to generate BA − -NH 4 + ••• − NO 2 -M (n−1)+ prior to its fragmentation into N 2 , 2H 2 O, BA − , and M (n−2)+ . 3,10,25 BA − is then converted to BA − -H + via protonation by H + roaming on or near La 3+ -O − / V 4+ , whereas M (n−2)+ binds with O M to regenerate O L =M n+ and terminates the LH-type model. 3,10 Although the ratedetermining step of the acidic cycle for the LH-type model remains unclarified, its energy barrier (E BARRIER,LH ) was reported to be lower than E BARRIER,ER .…”

“…3,10,25 BA − is then converted to BA − -H + via protonation by H + roaming on or near La 3+ -O − / V 4+ , whereas M (n−2)+ binds with O M to regenerate O L =M n+ and terminates the LH-type model. 3,10 Although the ratedetermining step of the acidic cycle for the LH-type model remains unclarified, its energy barrier (E BARRIER,LH ) was reported to be lower than E BARRIER,ER . 3,10,26,27 This indicates that the reduction of the former is not as effective as that of the latter in increasing low-temperature -r NOX .…”

“…3,4,[9][10][11]53 The areas under the resulting NO-TPD profiles (NO signals evolved versus temperature; Figure S11) were used to evaluate the numbers of NO adsorbed in a per-gram of the catalysts (N NO ) at 250 °C (Figure 5B). 3,4,[9][10][11]53 The N NO values of LaV 3 -S/LaV 3 -Sb-S (25−27 μmol NO g CAT −1…”