In situ DRIFTS studies on CuO-Fe2O3 catalysts for low temperature selective catalytic oxidation of ammonia to nitrogen

2017 ◽  
Vol 419 ◽  
pp. 733-743 ◽  
Author(s):  
Qiulin Zhang ◽  
Huimin Wang ◽  
Ping Ning ◽  
Zhongxian Song ◽  
Xin Liu ◽  
...  
Keyword(s):  
Low Temperature ◽  
Catalytic Oxidation ◽  
In Situ Drifts ◽  
Selective Catalytic Oxidation ◽  
Oxidation Of Ammonia

Low-temperature selective catalytic oxidation of ammonia over the CuO x /C-TiO2 catalyst

2014 ◽  
Vol 41 (8) ◽  
pp. 5743-5752 ◽  
Author(s):  
Hu Jingli ◽  
Tang Xiaolong ◽  
Yi Honghong ◽  
Li Kai ◽  
Sun Xin
Keyword(s):  
Low Temperature ◽  
Catalytic Oxidation ◽  
Tio2 Catalyst ◽  
Selective Catalytic Oxidation ◽  
Oxidation Of Ammonia

scholarly journals Catalytic Oxidation of Ammonia over Cerium-Modified Copper Aluminium Zinc Mixed Oxides

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6581
Author(s):  
Sylwia Górecka ◽  
Kateřina Pacultová ◽  
Dagmar Fridrichová ◽  
Kamil Górecki ◽  
Tereza Bílková ◽  
...  
Keyword(s):  
Low Temperature ◽  
Metal Oxides ◽  
Catalytic Oxidation ◽  
Catalytic Efficiency ◽  
Composition Analysis ◽  
High Catalytic Activity ◽  
Mixed Metal Oxides ◽  
Mixed Metal ◽  
Selective Catalytic Oxidation ◽  
Oxidation Of Ammonia

Copper-containing mixed metal oxides are one of the most promising catalysts of selective catalytic oxidation of ammonia. These materials are characterized by high catalytic efficiency; however, process selectivity to dinitrogen is still an open challenge. The set of Cu-Zn-Al-O and Ce/Cu-Zn-Al-O mixed metal oxides were tested as catalysts of selective catalytic oxidation of ammonia. At the low-temperature range, from 250 °C up to 350 °C, materials show high catalytic activity and relatively high selectivity to dinitrogen. Samples with the highest Cu loading 12 and 15 mol.% of total cation content were found to be the most active materials. Additional sample modification by wet impregnation of cerium (8 wt.%) improves catalytic efficiency, especially N2 selectivity. The comparison of catalytic tests with results of physicochemical characterization allows connecting the catalysts efficiency with the form and distribution of CuO on the samples’ surface. The bulk-like well-developed phases were associated with sample activity, while the dispersed CuO phases with dinitrogen selectivity. Material characterization included phase composition analysis (X-ray powder diffraction, UV-Vis diffuse reflectance spectroscopy), determination of textural properties (low-temperature N2 sorption, scanning electron microscopy) and sample reducibility analysis (H2 temperature-programmed reduction).

Promotional effects of ascorbic acid on the low-temperature catalytic activity of selective catalytic oxidation of ammonia over Pt/SA: effect of Pt0 content

2020 ◽  
Vol 44 (10) ◽  
pp. 4108-4113 ◽  
Author(s):  
Jingying Liu ◽  
Qingjin Lin ◽  
Shuang Liu ◽  
Shuhao Xu ◽  
Haidi Xu ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Catalytic Activity ◽  
Low Temperature ◽  
Catalytic Oxidation ◽  
Selective Catalytic Oxidation ◽  
Lower Temperature ◽  
Oxidation Of Ammonia

The amount of Pt species was increased by the addition of ascorbic acid to the Pt/SiAl catalyst, which shifted the temperature of the NH3-SCO reaction between NH3 and O2 to a lower temperature.

scholarly journals Insight into the Promoting Role of Er Modification on SO2 Resistance for NH3-SCR at Low Temperature over FeMn/TiO2 Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 618
Author(s):  
Huan Du ◽  
Zhitao Han ◽  
Xitian Wu ◽  
Chenglong Li ◽  
Yu Gao ◽  
...  
Keyword(s):  
Low Temperature ◽  
Catalyst Surface ◽  
Impregnation Method ◽  
In Situ Drifts ◽  
Tio2 Catalyst ◽  
Nh3 Scr ◽  
Nh3 Adsorption ◽  
So2 Resistance ◽  
Fast Scr

Er-modified FeMn/TiO2 catalysts were prepared through the wet impregnation method, and their NH3-SCR activities were tested. The results showed that Er modification could obviously promote SO2 resistance of FeMn/TiO2 catalysts at a low temperature. The promoting effect and mechanism were explored in detail using various techniques, such as BET, XRD, H2-TPR, XPS, TG, and in-situ DRIFTS. The characterization results indicated that Er modification on FeMn/TiO2 catalysts could increase the Mn4+ concentration and surface chemisorbed labile oxygen ratio, which was favorable for NO oxidation to NO2, further accelerating low-temperature SCR activity through the “fast SCR” reaction. As fast SCR reaction could accelerate the consumption of adsorbed NH3 species, it would benefit to restrain the competitive adsorption of SO2 and limit the reaction between adsorbed SO2 and NH3 species. XPS results indicated that ammonium sulfates and Mn sulfates formed were found on Er-modified FeMn/TiO2 catalyst surface seemed much less than those on FeMn/TiO2 catalyst surface, suggested that Er modification was helpful for reducing the generation or deposition of sulfate salts on the catalyst surface. According to in-situ DRIFTS the results of, the presence of SO2 in feeding gas imposed a stronger impact on the NO adsorption than NH3 adsorption on Lewis acid sites of Er-modified FeMn/TiO2 catalysts, gradually making NH3-SCR reaction to proceed in E–R mechanism rather than L–H mechanism. DRIFTS.

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