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

Abstract

There is an increasing demand to develop efficient SCR deNOx catalysts with high resistance to alkali and heavy metal. In this study, the V2O5-WO3/TiO2 (denoted as VWTi) catalyst modified with...

Improved NH3-SCR activity by the cooperation of FeVO4 and CeO2 nanosheet catalysts: structure and mechanism

“…When NH 3 was introduced, the observed bands of adsorbed NH 3 species corresponded to coordinated NH 3 on Lewis acid sites (1593, 1551, 1535 and 1197 cm −1 ), the NH 4 + species on Brønsted acid sites (1666 and 1420 cm −1 ) and amide species (1354 and 1321 cm −1 ). 4,18,47 There was no significant difference between the adsorbed NH 3 species and their peak intensity shown in Fig. S11a and that in Fig.…”

“…9a and b, after NH 3 adsorption and N 2 purge, the observed bands of adsorbed NH 3 species corresponded to coordinated NH 3 on Lewis acid sites (1593, 1551, 1533, 1234 and 1204 cm −1 ), NH 4 + species on Brønsted acid sites (1666 and 1420 cm −1 ) and amide species (1356 and 1329 cm −1 ). 4,18,47 As shown in Fig. S13a,† the NH 3 species adsorbed on CeO 2 -S were basically the coordinated NH 3 on Lewis acid sites (1593, 1568, 1550 and 1294 cm −1 ).…”

“…When NO was introduced, the bands of adsorbed NO x species including hyponitrite (1357 cm −1 ), monodentate nitrate (1490, 1294 and 1222 cm −1 ), bidentate nitrate (1543 cm −1 ) and bridging nitrate (1600 cm −1 ) were generated, as shown in Fig. S10a † 17,47 . When NO + O 2 were introduced, the generated NO x adsorbed species in Fig.…”

“…9c and d, after NO + O 2 adsorption and N 2 purge, the bands of adsorbed NO x species including monodentate nitrate (1490 cm −1 ), bidentate nitrate (1575 and 1543 cm −1 ) and bridging nitrate (1600 cm −1 ) were generated. 17,47 After converting the gas to NH 3 , the bands corresponding to coordinated NH 3 on Lewis acid sites (1597, 1551, 1533, 1234 and 1204 cm −1 ), NH 4 + species on Brønsted acid sites (1666 and 1420 cm −1 ) and amide species (1356 and 1319 cm −1 ) appeared and increased with time. It was observed that the bands of adsorbed NO x species and adsorbed NH 3 species overlapped at 1650–1475 cm −1 .…”

Extraordinary Detoxification Effect of Arsenic on the Cadmium-Poisoned V2O5/TiO2 Catalyst for Selective Catalytic Reduction of NOx by NH3

“…The disappearance of this peak over VTi− Cd&As indicated that the ammonia species were no longer adsorbed on the CdO sites because of the interaction between cadmium and arsenic. Combined with the reported DRIFT spectra of V-based catalysts, 58,59 the weak coordinated NH 3 peak at 1240 cm −1 over VTi−Cd&As was ascribed to the NH 3 adsorption on the partially recovered VO x Lewis acid sites. Given the key role of surface VO x sites in the NH 3 -SCR reaction, the negative band at 2048 cm −1 assigned to the loss of V�O groups reduced by ammonia was studied.…”