The Properties and SCR de‐NO_x Application of Supported V₂O₅/TiO₂ Catalysts with Different Polymerization State of VO_x Species Controlled by the pH Value of Their Precursors

Abstract

NO x is the main pollutant in the air, which causes many harmful effects on society. The V 2 O 5 /TiO 2 catalysts are very important to reduce the NO x from the heat engine plants and vehicle exhausts. However, various reasons will affect the performance of the catalysts. In this paper, the polymerization state of surface VO x of supported V 2 O 5 /TiO 2 catalysts was controlled by changing the pH value of the impregnation precursor solutions, and the redox and acidity properties of the catalysts can be adjusted consequently. The Raman spectroscopy, 51 V magicangle spinning nuclear magnetic resonance (MAS NMR), H 2temperature-programmed reduction (H 2-TPR), NH 3-temperature-programmed desorption (NH 3-TPD), NH 3-temperature-programmed oxidation (TPO) and 15 NH 3-NO-O 2-temperature-programmed surface reaction (TPSR) were mainly used for the characterization and properties tests of the samples. Although all catalysts in this work had similar surface morphology and the same vanadium loading, the catalyst oxidability decreased while acidity increased with the increasing of VO x polymerization, which causes the NO conversion increases with the increasing of VO x polymerization below 300°C in selective catalytic reduction (SCR) de-NO x reaction. This work will promote the advance in catalysis and anti-pollution fields for human and nature.

Polymerization State of Vanadyl Species Affects the Catalytic Activity and Arsenic Resistance of the V2O5–WO3/TiO2 Catalyst in Multipollutant Control of NOx and Chlorinated Aromatics

“…We then performed 51 V MAS NMR analyses to quantitively determine the different vanadyl species. Benefiting from sufficiently high fields and fast spinning rates, 51 V MAS NMR can provide detailed information on the local environment of the vanadyl species. − As shown in Figures and S11, the pristine VWT catalyst exhibited three vanadyl species: monomeric, dimer, and oligomer vanadyl species. For the VWT catalyst, the bands at 510 and 542 ppm were attributed to the monomer VO x structure (13.0%), while the band at 581 ppm was assigned to the dimeric vanadia structure (37.5%).…”

Electrocatalytic Performance of V2O5/Ti Composite Membrane for High-Efficiency Treatment of Ammonia Nitrogen Wastewater

“…Compared to our previous studies on catalysts TiO 2 and MnOx, V 2 O 5 is widely used in lithium-ion batteries, [28][29][30] supercapacitors, 31,32 gas sensitive sensor, 33,34 electrochromic materials 35,36 and catalytic destruction of hazardous organic compounds [37][38][39][40] owing to its abundant valence state (+2, +3, +5) as well as various chemical structures. 41 Researchers mainly adopted the sol-gel, 42 electrodeposition, 43 hydrothermal, 44 and magnetron sputtering 45,46 methods to prepare V 2 O 5 films. Due to its dense and uniform structure as well as excellent adhesion forces between the coating and substrate, the coating prepared by the magnetron sputtering method has received widespread attention.…”

Effect of HCl Treatment on Acidity of Pd/TiO2 for Furfural Hydrogenation

“…The transition metal TiO 2 can adjust the acidity of the surface through the formation of oxygen defects and changes in the acid density of Ti. For example, doping TiO 2 with metal oxides, such as SiO 2 , ZrO 2 , WO 3 , Al 2 O 3 , and V 2 O 5 , has been reported to increase the acidity of the surface and catalytic activity [18][19][20][21][22]. In addition, studies have reported the modification of the surface of TiO 2 by introducing functional groups via chemical treatment such as PO 4 3and SO 4 2- [23][24][25].…”