Catalysts
·
2021
·Vol. 11
·期 3
·324
·
IF 4.146
Jinkun Guan,Lusha Zhou,Weiquan Li,Die Hu,Jie Wen,Bichun Huang
SO2poisoning is a great challenge for the practical application of Mn-based catalysts in low-temperature selective catalytic reduction (SCR) reactions of NOxwith NH3. A series of Gadolinium (Gd)-modified MnOx/ZSM-5 catalysts were synthesized via a citric acid–ethanol dispersion method and evaluated by low-temperature NH3-SCR. Among them, the GdMn/Z-0.3 catalyst with the molar ratio of Gd/Mn of 0.3 presented the highest catalytic activity, in which a 100% NO conversion could be obtained in the temperature range of 120–240 °C. Furthermore, GdMn/Z-0.3 exhibited good SO2resistance compared with Mn/Z in the presence of 100 ppm SO2. The results of Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction of H2(H2-TPR) and temperature-programmed desorption of NH3(NH3-TPD) illustrated that such catalytic performance was mainly caused by large surface area, abundant Mn4+and surface chemisorbed oxygen species, strong reducibility and the suitable acidity of the catalyst. The in situ diffuse reflectance infrared Fourier transform spectra (DRIFTS) results revealed that the addition of Gd greatly inhibited the reaction between the SO2and MnOxactive sites to form bulk manganese sulfate, thus contributing to high SO2resistance. Moreover, in situ DRIFTS experiments also shed light on the mechanism of low-temperature SCR reactions over Mn/Z and GdMn/Z-0.3, which both followed the Langmuir–Hinshelwood (L–H) and Eley–Rideal (E–R) mechanism.Keywords:SO2poisoning;low temperature;NH3-SCR;in situ DRIFTS
研究领域:
催化化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2025
·
IF 4.8
Xinyu Liu,Chengxiong Wang,Feng Feng,Yinglong Wu,Shiying Chang,Guangxin Liu,Dong Tian,Weinan Yang,Xianming Cheng,Dongxia Yang,Kongzhai Li,Yunkun Zhao
Catalyst deactivation caused by SO 2 poisoning generally hinders commercial viability of CO oxidation catalysts in the field of industrial flue gas purification. XPS results, CO-DRIFTS spectra and DFT calculations suggested that Pt was highly-dispersed and remained the oxidative states on SnO 2 support, resulting in that the rate-determining step of CO oxidation is to clean up the adsorbed CO and PtS 2 species is readily formed in a SO 2 -contained hydrothermal environment. It predominantly maintained metallic Pt 0 in the Pt/WO 3 catalyst, thereby led to cleaning up the activated oxygen atoms as the rate-determining step. It is very difficult to remove the sulfur species in SO 2 -poisoned catalysts within 600 °C and the mechanisms of CO oxidation are not affected by SO 2 poisoning for Pt/SnO 2 and Pt/WO 3 catalysts. These findings provide some significant insights to understand the mechanisms of CO oxidation and SO 2 -tolerance.
研究领域:
催化化学
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环境科学
·
理论计算化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2025
·
IF 21.1
Xinyu Han,Kaijie Liu,Mengyao Bian,Zhaoxu Yuan,Yannan Li,Yunlong Zhang,Xiangguang Yang,Yibo Zhang
Despite SO 2 being recognized as a catalyst poisoning substance, a trace amount can enhance the acidity of the NH 3 -SCR (selective catalytic reduction) catalyst, which facilitates NH 3 adsorption and accelerates the reaction rate according to the Eley-Rideal mechanism. In this study, monoatomically dispersed Ce atoms were doped into the MoTiO x lattice to regulate the quantity and distribution of sulfate. This regulation was achieved by leveraging the stronger affinity of SO 2 to Ce, thus maximizing the acidifying effect of SO 2 to boost the NH 3 -SCR performance of the catalyst. The catalyst demonstrated the ability to maintain over 80 % NO x conversion for at least 144 hours in the presence of high concentration SO 2 (250 ppm). A detailed examination of the surface dynamics after SO 2 introduction revealed that NH 4 (SO 4 ) 2 , formed on the surface, converted to NH 4 HSO 4 . The decomposition of NH 4 HSO 4 extracted lattice oxygen from the catalyst, leading to an increase in oxygen vacancies on the catalyst surface as the duration of SO 2 exposure increased. The surface-adsorbed oxygen, brought about by these oxygen vacancies, was readily activated, which promoted the dehydrogenation process of NH 3 and the progression of NH 3 -SCR. Further, based on the discovery of the unique phenomenon and mechanism of NH 4 HSO 4 decomposition that generates oxygen vacancies, gases containing poisonous SO 2 were utilized for the pretreatment of the catalyst to optimize its surface and enhance its sulfur resistance (fighting poison with poison). The results demonstrated that the pretreated catalyst rapidly achieved optimal NO x conversion and maintained catalytic stability for over 240 h even in the presence of 250 ppm SO 2 without any decrease in activity. This research innovatively leveraged the poisonous SO 2 to optimize the catalyst's surface, thereby achieving higher catalytic performance and sulfur resistance, which offers valuable insights into the design of novel sulfur-resistant catalysts.
研究领域:
催化化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2019
·
IF 0
Limei Cao,Qian Wang,Ji Yang
A novel ultrafine Pt/Beta catalyst supported on carbon paper was prepared and applied to selective catalytic reduction of NO x by H 2 at a low temperature below 90 °C. Here, 0.8 wt.% Pt/Beta reached approximately 100 % NO conversion at 90 °C under oxygen-rich conditions (1000 ppm NO, 1 % H 2 , and 4 % O 2 ). The influence of the dispersion and particle size of Pt on the catalytic performance was investigated using Polyvinylpyrrolidone (PVP) as a structure directing agent to regulate the Pt particles. The feeding amount of PVP significantly influenced the catalytic activity of the catalysts. When the feeding amount was less than 50 mg, the Pt particle size was smaller, and the dispersion was higher, providing a higher NO conversion. However, when the feeding amount exceeded 50 mg, the dispersion no longer increased, and the activity slightly decreased. N 2 physisorption (BET) confirmed that excessive PVP decreased the specific surface area, which suppressed the catalytic activity of Pt/Beta. Moreover, the NO conversion efficiency was dependent on the dispersion and particle size of Pt and was minimally affected by the surface area of the catalysts. The Pt/Beta catalyst system was deactivated, and an irreversible poisoning phenomenon for SO 2 was observed. Zr, Ce, and V were introduced into the catalyst system as metal auxiliaries . The Ce-modified Pt-Ce/Beta catalyst prepared in this study showed resistance to SO 2 .
研究领域:
环境科学
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催化化学
✓ 已验证
DOI
Journal of Cleaner Production
·
2022
·
IF 11.072
Jiajin Huang,JiaYu Chen,Jinze Yao,Siyao Zhao,Xingbei Wu,Qibin Xia
The challenge for selective catalytic reduction (SCR) of NO x with NH 3 is to improve de-NO x activity at low temperatures while simultaneously improving the tolerance of catalysts towards SO 2 poisoning. Herein, V and Ce oxides were loaded on deactivated SCR catalysts subjected to acid pickling (CAT) via impregnation to recover de-NO x activity. The resulting V–Ce@CAT catalyst exhibited 85–95% NO x conversions over a wide temperature window of 200–450 °C while conversions of only 40–78% over the same temperature range were observed with CAT (spent catalyst treated with acid). Interestingly, in addition to the high tolerance towards SO 2 displayed by V–Ce@CAT, the catalyst exhibited improved reactivity after the introduction of 200 ppm SO 2 , with the NO x conversion increasing from 80% to 87%. The results indicated that a kinetic equilibrium was reached between the formation and decomposition rates of Ce 2 (SO 4 ) 3 on V–Ce@CAT which prevented the accumulation of surface sulfate species, thereby protecting the main active species V from catalytic inactivation. Furthermore, in situ DRIFTS revealed that the NH 3 -SCR reaction pathway of V–Ce@CAT follows the L-H mechanism.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2021
·
IF 3.171
Xin Yong,Hong Chen,Huawang Zhao,Miao Wei,Yingnan Zhao,Yongdan Li
The effects of SO 2 on an one-pot synthesized Cu-SSZ-13 catalyst for selective reduction of NO x by NH 3 were examined. The addition of SO 2 inhibited NO x conversion significantly below 300 °C, while no effect on NO x conversion was observed above 300 °C. TGA, TPD , and XPS results showed that the deactivation was caused by the formation of (NH 4 ) 2 SO 4 , SO 2 chemisorption on the isolated Cu 2+ ion sites, as well as the formation of CuSO 4 -like species. Among them, the site-blocking effect of (NH 4 ) 2 SO 4 on Cu 2+ was the primary reason for deactivation. Fortunately, 89% of deNO x activity of the poisoned catalyst was recovered after thermal treatment at 500 °C in air, where (NH 4 ) 2 SO 4 was completely decomposed. The activity was further recovered with regeneration temperature increasing to 600 °C, removing the adsorbed SO 2 on the Cu 2+ sites. The regeneration at 600 °C could not recover the activity completely, because of the high stability of CuSO 4 -like species.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2019
·Vol. 21
·期 4
·1-7
·
IF 2.009
Xie Chong,Shi Jian-Wen,Yang Shenghui,Li Xifei
The MnO x -TiO 2 /MWCNTs nanocomposites were used as De-NO x catalysts to study the deep-rooted reason for the deactivation. Based on a series of characterization on as-prepared catalyst and poisoned catalyst, the results showed that the chief culprit for the deactivation is the micropores in the De-NO x catalyst. The formed ammonium (bi)sulfate in the micropores during the SCR reaction process could not be took away by the gas flow soon and then deposited on the catalyst surface gradually, and further covered the active sites. And the poisoned catalysts could be recovered partly rather than fully by heat treatment at 500 °C because of the decomposition of the ammonium (bi)sulfate and the phase transition of the TiO 2 .
研究领域:
环境催化
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纳米材料科学
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大气污染控制
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2015
·
IF 3.368
Xiaole Weng,Xiaoxia Dai,Qingshan Zeng,Yue Liu,Zhongbiao Wu
Heteropoly acids (HPAs) have been effectively utilized in selective catalytic reduction (SCR) of NO to improve the NH 3 absorption capacity and alkaline/alkali metal resistance for SCR catalysts. However, despite the promise on super-acidities, their other properties that would work on SCR process are still lack of exploration. In this study, a 12-tungstaphosphoric acid (H 3 PW 12 O 40 , HPW) was selected to modify a well-reported CeO 2 catalyst. The resulted CeO 2 /HPW catalyst was subsequently utilized for SCR of NO with excess NH 3 , which revealed a significantly promoted performance in SCR reaction. DRIFT analyses showed that the unique NO 2 absorption capacity of HPW could prevent the NO 2 being further oxidized into nitrate species and the abundant Brønsted acid sites could effectively retain the NH 3 , avoiding them being over-oxidized at evaluated temperatures. The presence of NO 2 was demonstrated able to induce a so called “fast SCR” reaction over the CeO 2 /HPW catalyst, which effectively facilitated the SCR reaction. Furthermore, we have also constructed a CeO 2 @HPW catalyst, which showed an enhanced SO 2 poisoning resistance in SCR reaction.
研究领域:
环境科学
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催化化学
✓ 已验证
DOI
PubMed
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2019
·Vol. 128
·期 2
·681-693
·
IF 1.428
Xie Chong,Yang Shenghui,Shi Jian-Wen,Niu Chunming
A novel MnO x –TiO 2 catalyst with hollow silkworm structure was synthesized successfully via an ethanol-thermal strategy by using activated carbon fiber felt as template for the first time. The silkworm-like MnO x –TiO 2 catalyst (MnTi) exhibited higher NO x conversion in the whole experimental temperature region (90–330 °C) under a high space velocity of 36,000 h −1 in comparison with the common MnO x –TiO 2 catalyst without hollow silkworm structure (MnTi-B). The excellent catalytic performance of MnTi can be attributed to its high specific surface area, large content of active surface oxygen species (O S ), and more surface acid sites. In addition, the MnTi catalyst also exhibited excellent resistance to water or SO 2 poisoning.
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2025
·
IF 4.8
Xiao Yang,Heying Zhao,Aiyong Wang,Wangcheng Zhan,Yanglong Guo,Li Wang,Xuan Tang,Yun Guo
SO 2 in the sintering flue gas severely inhibits the CO oxidation performance of commercial Pt/Al 2 O 3 catalysts. However, the major poisoning mechanism of SO 2 on Pt/Al 2 O 3 in CO oxidation in the presence of H 2 O remains to be elucidated. Here, Pt/Al 2 O 3 was pretreated with different reducing atmospheres at high temperatures. Among these, the catalyst pretreated with a CO atmosphere at 600 °C (denoted as Pt/Al 2 O 3 -CO-600) exhibited superior CO oxidation performance and enhanced sulfur resistance in the presence of both H 2 O and SO 2 . The combination of XPS, HAADF-STEM, TG-MS, SO 2 oxidation test, and in-situ DRIFTS reveal that the Pt species on Pt/Al 2 O 3 -CO-600 transformed from Pt oxide clusters to metallic Pt nanoparticles. This transformation enhanced SO 2 adsorption and reactivity, leading to increased sulfate accumulation. Despite the high SO 2 reactivity and sulfate content, in-situ DRIFTS revealed that the CO reaction of Pt/Al 2 O 3 -CO-600 was less hindered by SO 2 and the sulfated Al 2 O 3 . This is attributed to the high ratio of the under-coordinated (UC) Pt sites in Pt/Al 2 O 3 -CO-600, which promotes the reaction intermediates spillover from Pt site to Al 2 O 3 compared to the Pt/Al 2 O 3 . This phenomenon was positively correlated with the sulfur resistance of reduced catalysts. Accordingly, the UC site contributes to the spillover of sulfate intermediate (H 2 SO 4 ), reducing the CO reactivity loss of Pt/Al 2 O 3 due to the intermediate coverage. This study elucidates that the primary poisoning pathway of Pt/Al 2 O 3 in the presence of H 2 O and SO 2 is the difficulty of sulfate intermediate spillover.
研究领域:
催化化学
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环境化学
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材料科学
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表面科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2025
·
IF 21.1
Cangpeng Shan,Qinwei Jia,Yan Zhang,Guoshuai Liu,Xinyu Hou,Yunchong Wang,Rui Han,Caixia Liu,Weichao Wang,Qingling Liu
Removing industrial source CO through catalytic oxidation and providing heat for denitrification units have significant economic and environmental benefits. Sulfur poisoning of catalysts is the bottleneck to stabilize the system operation. To overcome this problem, we fabricated sulfate modified Pt/TiO 2 by appropriate NH 4 HSO 4 deposition, which survived in the SO 2 environment with the concentration as high as 1000 ppm SO 2 , and exhibited an outstanding stability with over 90% CO conversion at 200 °C for 500 h under a typical steel sintering flue gas condition. Experimental and theoretical explorations confirmed that the electronic structure of PtO x clusters was optimized through Pt-O-S bridges after sulfate modification. The O 2p band center closer to the Fermi level and the smaller energy difference between Pt 5d and O 2p band centers led to more active lattice oxygen of PtO x clusters. The more stable π back bonding between Pt 5d and CO 2p and weaker hybridization between Pt and the π⁎ (Ssp2-Osp2)2 orbital of SO 2 indicated enhanced CO adsorption while weakened SO 2 adsorption on Pt sites. The above factors simultaneously improved the low-temperature activity and sulfur resistance for CO oxidation over sulfate modified Pt/TiO 2 . This work provides new insights for the design of sulfur-resistant catalysts and the understanding on the effect of sulfates on catalytic activity.
研究领域:
催化化学
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环境化学
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材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）