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It is still a serious challenge to develop a simple synthesized method of SAPO‐34 sieve modified by Cu with high NH3‐SCR performance. The Cu/SAPO‐34 samples with hierarchical structure were synthesized for the first time using cupric citrate as copper source by one‐pot hydrothermal method which showed excellent NH3‐SCR performance for NO removal. Among them, the 0.15Cu/SAPO‐34 catalyst with a Cu/Al ratio of 0.15 exhibited the widest temperature operating window (160–500 °C) and better hydrothermal stability. The physicochemical properties of 0.15Cu/SAPO‐34 was measured to understand the impacts of the Cu species on the NH3‐SCR of NO activity by various characterization methods including XRD, NH3‐TPD, N2 adsorption‐desorption, XPS, EPR, UV‐vis, NH3‐oxidation, NMR and in situ DRIFTS. The results reveal that the good activity is assigned to the isolated Cu species located at the site (I) in SAPO‐34, and the co‐existence of surface Cu2+ and Cu+ species with almost equal amounts. In addition, 0.15Cu/SAPO‐34 also possesses suitable acidic sites which are conducive to catalytic activity. The results of in situ DRIFTS suggest that the NH3‐SCR reaction follows Eley‐Rideal mechanism over 0.15Cu/SAPO‐34. [ABSTRACT FROM AUTHOR]

Cu ion-exchanged SAPO-34 with hierarchical pore structure (Cu/SAPO-34-H) presents excellent NH 3 -SCR activity, which is attributed to the active Cu species located in D6R. • Preparation of Cu/SAPO-34-H with hierarchical pore structure by ion exchanged method. • High NH 3 -SCR of NO x activity over 2.7 wt%Cu/SAPO-34-H at 170–480 °C even under 10%H 2 O. • Excellent SCR activity due to Cu2+ mainly located in D6R in Cu/SAPO-34-H. • Hierarchical pore structure promote the generation stability and of active Cu species. • Much better hydrothermal stability at either high temperature or low temperature. SAPO-34 with hierarchical pore structure (SAPO-34-H) was first prepared by a hard-template method using CaCO 3 as template. The x Cu/SAPO-34-H (x = 1.1 wt%, 1.9 wt%, 2.7 wt% and 3.2 wt%) catalysts were synthesized by ion-exchanged method and applied for selective catalytic reduction (SCR) of NOx with NH 3. XRD, XRF, SEM, TEM, UV–vis-DRS, NH 3 -TPD, XPS, NMR, EPR and in situ DRIFTS were used to characterize the physiochemical properties of the catalysts. The SCR activity results demonstrate that 100% NOx conversion can be achieved over the 2.7 wt%Cu/SAPO-34-H catalyst at about 150 °C in the GHSV of 40,000 h−1. Furthermore, NOx conversion under the testing conditions of H 2 O and SO 2 was slightly influenced over the 2.7 wt%Cu/SAPO-34-H catalyst after high-temperature hydrothermal aging at 700 and 800 °C, respectively. NOx convention presents above 90% at 170–480 °C even introducing 10% H 2 O for 10 h, and it can be maintained 90% by introducing 200 ppm SO 2 and 12% H 2 O over 2.7 wt%Cu/SAPO-34-H. In the meantime, 2.7 wt%Cu/SAPO-34-H was investigated through the low-temperature hydration treatment at 80 °C, it also displays superior hydration treatment resistance for low-temperature. The outstanding performance is ascribed to the hierarchical pore structure of 2.7 wt%Cu/SAPO-34-H, which can promote the diffusion of reaction gas and generation of active sites. EPR results indicate that the Cu2+ species mainly locates the site I in 2.7 wt%Cu/SAPO-34-H, while the Cu2+ species mainly locates the site III for the conversional 2.7 wt%Cu/SAPO-34. Moreover, the in situ DRIFTS results indicate that the Lewis acid sites are easy to participate in NH 3 -SCR reaction for 2.7 wt%Cu/SAPO-34-H, which mainly follows the Eley-Rideal (E-R) reaction mechanism at 200 °C for 2.7 wt%Cu/SAPO-34-H. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tar induced severe deactivation of SCR catalyst is first reported in China. • Proposed pyrolysis effectively removes the poisoning substances. • Heating rate is the critical factor to keep a superior mechanical property. • The generated catalyst show activity as high as the fresh catalyst. • Regeneration of SCR catalyst shows favorable environmental and economic benefits. Tar species on catalyst's surface promote the deposition of NH 4 HSO 4 /(NH 4) 2 SO 4 leading to the complete deactivation of V 2 O 5 -MoO 3 /TiO 2 catalyst utilized in a glass kiln. The proposed pyrolysis method in this work effectively removes the poisoning substances. TG-IR and TG-MS results indicate that the pyrolysis products are mainly CO 2 and SO 2 representing the pyrolysis of tar species and NH 4 HSO 4 /(NH 4) 2 SO 4. The heating rate and pyrolysis temperature are the critical factors to keep a superior mechanical property. The axial and transverse compressive strength remained 1.77 MPa and 0.53 Mpa falling only by 4.8% and 13.1% respectively through the optimized treatment at 420 °C for 2 h with heating rate of 3 K min−1. The characterizations indicated that the surface area, pore volume and acid property were apparently restored after the heat treatment. As a result, the regenerated powder catalyst showed 100% NO conversion and more than 94% N 2 selectivity at 250 – 300 °C and the regenerated honeycomb catalyst exhibited 91.6% NO conversion at 260 °C. The TPR and XPS results indicated changes of the redox behavior, which contracted the temperature range of excellent performance. Typically, the redox cycles shifting to high temperatures narrowed this temperature range, while the excessive oxidation ability decreased the N 2 selectivity. The schematic of tar induced deactivation and regeneration was proposed. Overall, the tar induced deactivated catalyst was successfully regenerated by proper pyrolysis and can be reutilized in the original glass kiln at 260 °C. [ABSTRACT FROM AUTHOR]

• Good activity in range of 210–420 °C with 100% NO conversion and N 2 selectivity. • The special activity due to more surface acid amount and suitable redox ability. • Monodentate nitrate and NH 2 species as main active intermediates. • H 2 O mainly restrains L-H reaction pathway leading to the deactivation of catalyst. A serial of novel Ni m Co 0.3-m Ti 0.7 O x (m = 0.05-0.25) mixed-oxide catalysts was synthesized by sol-gel method, and applied for selective catalytic reduction (SCR) of NO x by NH 3. Influences of the Ni/Co ratio on the physi co- chemical properties and SCR performance were characterized by various analytical techniques, including BET surface area, XRD, XPS, NH 3 -TPD, H 2 -TPR and in situ DRIFTS. The Ni 0.1 Co 0.2 Ti 0.7 O x catalyst shows optimum NH 3 -SCR activity and excellent N 2 selectivity with a broader activity temperature window (210–450 °C), which is associated with the much higher BET surface area, more surface acid amounts and the suitable redox ability derived from the strong interaction between Co and Ni (Co3+ + Ni2+ ↔ Ni3+ + Co2+). In situ DRIFTS results reveal that the formed monodentate nitrate and NH 2 species, as main active intermediates, are favor of the NH 3 -SCR reaction. The existence of H 2 O mainly restrains Langmuir-Hinshelwood reaction pathway which may be the main cause for the catalyst deactivation. [ABSTRACT FROM AUTHOR]