Synergistic degradation mechanism of chlorobenzene and NO over the multi-active center catalyst: The role of NO2, Brønsted acidic site, oxygen vacancy

V2O5–WO3/TiO2 Catalyst for Efficient Synergistic Control of NOx and Chlorinated Organics: Insights into the Arsenic Effect

“…The phenolates were then attacked by the oxygen of V–O–V bands and yielded the catecholate (1597 cm –1 ) and benzoquinone species (1676 cm –1 ), which had been further oxidized into maleates (1521 and 1320 cm –1 ) and the final products such as CO 2 and H 2 O. Comparing to Brønsted V–OH, the Ti–OH was shown much favorable to react with Cl free forming HCl, as the reaction energy of (−V–OH) + Cl free → −V–OHCl ad was calculated as high as 7.62 eV . Furthermore, both the V–OH (Brønsted acid sites) and VO species (Lewis acid sites) were involved in the SCR reaction.…”

“…The presence of the 1736 cm –1 band (CO of imide structures) indicated that the adsorbed NH 3 had been involved in the CBCO reaction. These NH 3 species can dissociate H protons that provides additional Brønsted acidic sites for Cl conversion . With increased arsenic loading, the bands of p -benzoquinone (1676 cm –1 ), catechol (1597 cm –1 ), and maleate (1320, 1521 cm –1 ) all increased, suggesting that the cleavage of aromatic rings was enhanced.…”

“…Comparing to Brønsted V−OH, the Ti−OH was shown much favorable to react with Cl free forming HCl, as the reaction energy of (−V−OH) + Cl free → −V−OHCl ad was calculated as high as 7.62 eV. 11 Furthermore, both the V−OH (Brønsted acid sites) and VO species (Lewis acid sites) were involved in the SCR reaction. The NH 3 appeared to be preferentially adsorbed on the V−OH sites (V 5+ −OH), activating through the transfer of H proton to V 5+ O forming the…”

“…Both of them can emit a range of harmful organic and inorganic substances that endanger the environment and human health; these include NO x , SO 2 , heavy metals (Pb, As, etc. ), and polychlorinated dibenzo- p -dioxins and polychlorinated dibenzofurans (PCDD/Fs). , Owing to the risk of toxic waste generation by the activated carbon injection technique, much effort has been made to develop advanced catalysts for the synergistic control of PCDD/Fs with the assistance of devices for NH 3 -selective catalytic reduction (SCR) of NO x . − Among formerly investigated catalysts, the V 2 O 5 –WO 3 /TiO 2 catalyst has shown to be highly efficient for PCDD/Fs destruction. − Since the 1990s, the company Shell has embedded this catalyst in a Shell dioxin destruction system (SDDS), which achieved at least 85% removal efficiency of PCDD/Fs at 220 °C . However, the complex components in the MSWI and ISSI flue gases often result in mutual interference in the synergistic process, which thereby profoundly affect the synergistic activity of V 2 O 5 –WO 3 /TiO 2 catalyst …”

Feasible Tuning of Surface OVs on (001) TiO2 for Superior Photocatalytic Nitrogen Fixation Activity

“…For instance, ternary metal oxides, hydrous oxides and bismuth oxyhalides have been modified with surface OVs to trigger nitrogen fixation activities in many pioneering researches. [9][10][11][12][13][14] Via a conventional solid phase reduction with NaBH 4 , the reduced TiO 2 prepared by Mi and his co-workers obtain a good N 2 photo-fixation rate to 324.86 μmol • g À 1 • h À 1 under full spectrum illumination. [15] Yu et al synthesized defective TiO 2 nanotubes through annealing under Ar/H 2 atmosphere and a following amine-assisted remedying process.…”