Hydrothermal Aging Treatment Activates V₂O₅/TiO₂ Catalysts for NO_x Abatement

Abstract

Thermal stability is crucial for the practical application of deNO x catalysts. Vanadia-based catalysts are widely applied for the selective catalytic reduction of NO x with NH3 (NH3-SCR). Generally, hydrothermal aging at high temperatures induces the deactivation of deNO x catalysts. However, in this work, a remarkable increase in low- and medium-temperature NH3-SCR activity was observed for a V2O5/TiO2 catalyst after hydrothermal aging treatment, especially at 750 °C for 16 h. After the vanadia-based catalyst was hydrothermally treated at 750 °C, the specific surface area decreased and the surface VO x density and surface V ratio increased significantly. Therefore, the aged catalyst presented more abundant polymeric vanadyl species than the fresh one. Furthermore, the redox capability was improved markedly after hydrothermal treatment due to the strong interaction of vanadia and titania, contributing to the NH3-SCR reaction. 750 °C is the optimal temperature to activate the V2O5/TiO2 catalyst, improving the SCR performance significantly. This study provides an in-depth understanding of vanadia-based catalysts for practical applications.

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

“…Figure a illustrates the H 2 -TPR profiles of the catalysts, and the H 2 consumption is listed in Table . It was found that a main peak was located at 381 °C on the VTi catalyst, which was ascribed to the reduction of surface V 5+ species. ,, When cadmium was incorporated into the catalyst, the V 5+ reduction peak shifted to a lower temperature (311 °C) with a significantly reduced intensity, and a reduction peak of Cd 2+ appeared (271 °C). , It meant that the reduction of V 5+ species was strongly restrained, resulting from the interaction between cadmium and vanadium. After arsenic doping, the overlapping of As 5+ (395 °C) , and V 5+ (407 °C) species reduction peaks was recorded over VTi–As with an increased H 2 consumption (0.16 mmol/g).…”

“…It was found that a main peak was located at 381 °C on the VTi catalyst, which was ascribed to the reduction of surface V 5+ species. 21,43,51 When cadmium was incorporated into the catalyst, the V 5+ reduction peak shifted to a lower temperature (311 °C) with a significantly reduced intensity, and a reduction peak of Cd 2+ appeared (271 °C). 15,18 It meant that the reduction of V 5+ species was strongly restrained, resulting from the interaction between cadmium and vanadium.…”

Electron Donation from Boron Suboxides via Strong p–d Orbital Hybridization Boosts Molecular O2 Activation on Ru/TiO2 for Low-Temperature Dibromomethane Oxidation

“…21-1272) and rutile (JCPDS No. 21-1276) phases of crystalline TiO 2 were identified without boric acid or titanium borate impurities. No Ru diffraction peak was identified due to the low loading and/or high dispersion.…”

Coupling effects between metal–organic framework derivatives and oxygen-deficient TiO2 nanotubes: identified charge-transfer processes and photoelectric synergistic effect

“…TiO 2 as a semiconductor metal oxide makes it easy to synthesize the TiO 2 -NTs (TNTs) structure with adjustable shape, in which tubular structures are considered the most suitable method for achieving more significant surface area increases without increasing the geometric area. 13 By modifying the reaction conditions, TNTs produced by anodic oxidation and electrochemical reduction may accurately regulate the structural characteristics (pore size, wall thickness, and length). A strong support structure is provided by the ordering and the closely packed nanotubes, which enables the loading of a particular photoactive material and lessens the loss of light reflection brought on by various radiation scatters.…”