Catalysis Science & Technology
·
2021
·Vol. 11
·期 22
·7467-7474
·
IF 6.119
Yangfan Ming,Gang Li
When Cu–TEPA (Cu2+ coordinated with tetraethylenepentamine) is used as a template in the one-pot synthesis of Cu–SSZ-13, Cu2+ will be reduced to Cu0, resulting in a too high Cu content in the product. Herein, by adding iron complexes to the precursor, the reduction of Cu2+ could be inhibited and FeCu–SSZ-13 samples with rational Cu and Fe contents were prepared by a simple one-pot strategy. Although these samples show high activity in the NH3-SCR at low temperature, their high temperature performance is poor due to the lack of strong NH3 adsorption sites such as Brønsted acid sites. Meanwhile, different iron complexes were used as iron sources to synthesize FeCu–SSZ-13, and among them the sample with sodium nitroprusside shows the highest activity. Due to the large ionic radius of K+, it is easily retained which blocks the pores, so the performance of the samples synthesized with a K-type iron source is poorer than that of their Na-type counterparts. Moreover, the activity of the catalyst synthesized with an Fe3+ source is higher than that synthesized with an Fe2+ source because the valence state of Fe sources has a great influence on the Fe chemical state in the catalysts.
研究领域:
催化化学
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Yiqing Zeng,Fengye Lyu,Yanan Wang,Shule Zhang,Qin Zhong,Zhaoxiang Zhong
High N 2 O selectivity of MnO x -TiO 2 catalyst hinders its development in ammonia selective catalytic reduction (NH 3 -SCR) of NO x . Herein, a series of MnO x -TiO 2 catalyst with different Mn/Ti ratio were prepared by wet-impregnation method to study the N 2 O formation during ammonia selective catalytic reduction (NH 3 -SCR) of NO x from the perspective of catalyst. It is found that MnO x and TiO 2 species are the mainly redox and acid sites for the NH 3 -SCR denitration reaction over MnO x -TiO 2 catalyst, respectively. As the Mn/Ti ratio increases, MnO x species layer expanded on TiO 2 support, leading to increase of redox sites but decrease of surface acid sites. These changes contribute to the occurrence of the no-selective oxidation of NH 3 on MnO x species and the over-activation of NH 3 at Mn-Ti interface, resulting in the formation of N 2 O via the route of 2NH 3 + 2O 2 → N 2 O + 3H 2 O and 4NO + 4NH 3 + 3O 2 → 4N 2 O + 6H 2 O, respectively. Through this work, it can be speculated that both improving MnO x dispersion and increasing surface acidity of catalyst are feasible strategy for suppressing the N 2 O formation on MnO x -TiO 2 .
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Sciences
·
2022
·
IF 6.796
Zhihui Lv,Guangzhi He,Wenshuo Zhang,Jingjing Liu,Zhihua Lian,Yang Yang,Zidi Yan,Guangyan Xu,Wenpo Shan,Yunbo Yu,Hong He
TiO 2 -supported V 2 O 5 catalysts are commonly used in NO x reduction with ammonia due to their robust catalytic performance. Over these catalysts, it is generally considered that the active species are mainly derived from the vanadia species rather than the intrinsic structure of V-O-Ti entities, namely the interface sites. To reveal the role of V-O-Ti entities in NH 3 -SCR, herein, we prepared TiO 2 /V 2 O 5 catalysts and demonstrated that V-O-Ti entities were more active for NO x reduction under wet conditions than the V sites (V=O) working alone. On the V-O-Ti entities, kinetic measurements and first principles calculations revealed that NH 3 activation exhibited a much lower energy barrier than that on V=O sites. Under wet conditions, the V-O-Ti interface significantly inhibited the transformation of V=O to V-OH sites thus benefiting NH 3 activation. Under wet conditions, meanwhile, the migration of NH 4 + from Ti site neighboring the V-O-Ti interface to Ti site of the V-O-Ti interface was exothermic; thus, V-O-Ti entities together with neighboring Ti sites could serve as channels linking NH 3 pool and active centers for activation of NH 4 + . This finding reveals that the V-O-Ti interface sites on V-based catalysts play a crucial role in NO x removal under realistic conditions, providing a new perspective on NH 3 -SCR mechanism.
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Inorganic and Nano-Metal Chemistry
·
2021
·
IF 1.716
Changsheng Qu,Hao Zhou,Dongyao Xu,Jiaojiao Guo,Danyang Zhao,Xuewei Guo,Luyuan Xing
In this study, the manganese was loaded on three different zirconia crystal types by ultrasonic impregnation method, and the performance of selective catalytic reduction (SCR) of NOx with NH3 was tested. The characteristics of the catalytic were tested by BET, XRD, SEM, and XPS. It was founded that the performances of unloaded different crystal zirconia was basically the same which were less than 40%. Compared with unloaded catalyst, the DeNOx performance of catalysts after loaded manganese was greatly improved, and the crystal type had obvious influence on the DeNOx performance of Mn/x-ZrO2. The Mn/m-ZrO2 had the highest DeNOx performance (90.97% at 240 °C) compared with the Mn/t-ZrO2 and Mn/c-ZrO2. The difference of crystal type made Mn/m-ZrO2 have lower surface Mn average valence states and more oxygen vacancy, which made it have best DeNOx performance. The effects of SO2, H2O, and alkali metal on DeNOx efficiency were also tested.
研究领域:
环境科学
·
催化材料科学
✓ 已验证
DOI
高影响因子
NEUROPHARMACOLOGY
·
2020
·
IF 4.431
Aijing Bi,Wenji An,Chunmei Wang,Yao Hua,Fang Fang,Xiaoliang Dong,Rong Chen,Zhengping Zhang,Lan Luo
Except for few symptoms-improved drugs for Alzheimer's disease (AD), no disease-modified drug has been developed, especially for AD in type 2 diabetes mellitus (T2DM). SCR-1693, a disease-mortified candidate for AD, which is now in Phase I clinical study in China, improves Aβ 25 – 35 -impaired cognitive function in rodent's models. Here we report the effect of SCR-1693 on regulation of tau phosphorylation and insulin resistance associated cognition, and illustrate its underlying mechanism. We found that in intracerebroventricular injection of streptozotcin (STZ) rats, oral administration of SCR-1693 dose-dependently improved the learning and memory in Morris water maze test, decreased tau hyperphosphorylation , astrogliosis and postsynaptic protein loss in hippocampus . In Neura-2a cells with stable transfection of full-length human tau (Neura-2a-tau), treatment of SCR-1693 concentration-dependently enhanced the activation of protein phosphatase (PP1) and protein phosphatase 2A (PP2A), decreased cellular tau phosphorylation, and increased insulin-induced cellular signaling to reverse insulin resistance. Pre-treatment with the inhibitor of PP1 and PP2A inhibited the effect of SCR-1693 on both of tau phosphorylation and insulin signaling in Neura-2a-tau cells. All data suggest that an increase of activity of tau phosphatase was involved in the mechanism of SCR-1693 on the regulation of tau phosphorylation and insulin signaling, and SCR-1693 is considerable candidate for insulin resistance associated sporadic AD.
研究领域:
神经科学
·
药理学
·
糖尿病
·
阿尔茨海默病
✓ 已验证
DOI
PubMed
高影响因子
Catalysts
·
2022
·Vol. 12
·期 11
·1430
·
IF 4.501
Yang Gao,Li Cao,Xiaodong Wu,Xu Zhang,Ziran Ma,Rui Ran,Zhichun Si,Duan Weng,Baodong Wang
CeNbTi catalyst was poisoned in different sulfur poisoning atmospheres at 300 °C for 6 h and then was evaluated for selective catalytic reduction (SCR) of NOxwith NH3. The catalyst deactivation upon SO2exposure was effectively inhibited in the presence of NH3. Temperature-programmed decomposition (TPD) analyses were applied to identify deposit species on the poisoned catalysts by comparison with several groups of reference samples. Diffuses reflectance infrared Fourier transform spectroscopy (DRIFTS) over CeNbTi catalysts with different poisoning pretreatments and gas purging sequences were designed to investigate the roles of NH3in the removal of surface sulfites and sulfates. More ammonium sulfates including ammonium bisulfate and ammonium cerium sulfate were generated instead of inert cerium sulfate in these conditions. The mechanisms about the formation and transformation of surface deposits upon sulfur poisoning w/wo NH3were explored, which provided a basis for developing Ce-based mixed oxides as SCR catalysts for stationary sources.Keywords:ceria;SCR;sulfur;NH3;TPD;DRIFTS;deposit
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Minghu Zhao,Jiuhu Zhao,Ran Ding,Rongshu Zhu,Haiyan Li,Zhi Li,Jingwen Zhang,Yongji Zhu,Huiying Li
The existence of sulfur dioxide and water vapor in the flue gas generated from waste-to-energy stations could lead to catalyst deactivation , which has adverse effects on NO x removal. It is thus particularly important to study the reaction mechanism of catalyst resistance to poisoning. Herein, we report the mechanism of In-Co 3 O 4 -Ga 2 O 3 /H-Beta catalyst to SO 2 and H 2 O resistance in the selective catalytic reduction (SCR) of NO x by CH 4 . The catalyst could achieve 74.6% NO x removal efficiency in the presence of 100 ppm SO 2 and 5% H 2 O. In this catalyst, Co 3 O 4 is attributed to enhancing the reversible poisoning of SO 2 and CH 4 activation and increasing the number of Brønsted acid sites by decomposing H 2 O. However, the InO + active center was still eroded by a small amount of water vapor, leading to a reduction in NO x removal efficiency. The addition of Ga 2 O 3 primarily provided an important intermediate NO 2 for CH 4 -SCR reaction and reduced the aggregates of Co 3 O 4 to increase the exposure of indium sites, and could reduce a part of SO 2 to S 2− . This study provides a good candidate for preparing catalysts with superior resistance towards SO 2 and H 2 O for CH 4 -SCR.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Zhong-yi Wang,Rui-tang Guo,Zhen-zhen Guan,Xu Shi,Wei-guo Pan,Zai-guo Fu,Hao Qin,Xing-yu Liu
A sequence of Cr-modified CeZr 2 O x catalysts were synthesized through the co-precipitation way and applied in selective catalytic reduction (SCR) of NO x with ammonia. The optimal catalyst (Cr 1 CeZr 2 O x ) exhibited the excellent NH 3 -SCR activity and high SO 2 resistance. From the characterization results, Cr species in Cr 1 CeZr 2 O x could suppress the formation of ZrO 2 crystals, which could also contribute to stronger surface acidity and reducibility . Besides, more Ce 3+ and surface adsorbed oxygen species were observed on Cr 1 CeZr 2 O x catalyst. On the basis of in situ DRIFT experiments, it could be confirmed that the NH 3 -SCR process on Cr 1 CeZr 2 O x was promoted through Langmuir-Hinshelwood (L-H) mechanism. Besides, the improved NO oxidation and more ad-NO x and ad-NH 3 also played a vital role for the superior low-temperature SCR activity of Cr 1 CeZr 2 O x .
研究领域:
催化化学
·
环境科学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 27
·15238-15245
·
IF 12.732
Linying Wang,Dali Zhu,Juan Wang,Wenhao Cui,Jingfeng Han,Bing Li,Dong Fan,Peng Tian,Zhongmin Liu
An X-ray amorphous material with a CHA-like structure, named embryonic CHA zeolite, has been designed and employed for the synthesis of SSZ-13, which leads to ultra-fast crystallization (1.5–12 h), wide product SiO2/Al2O3 ratio (SAR = 22–100) and high yield (82.8–92.9%). The usage of N,N,N-trimethyl-1-adamantammonium hydroxide (TMAdaOH) for the synthesis can be controlled at unprecedentedly low amounts (TMAdaOH/SiO2 = 0.035–0.050). Characterization results reveal that the embryonic zeolite has a small particle size of 10–20 nm, large micro/mesopore volume and abundant double 6-ring units (subunits of the CHA structure). It provides ample active surface and subunits for the formation of the CHA structure and promotes the fast synthesis of SSZ-13 with a wide phase region. The resultant material (SAR = 23.2), after Cu2+ exchange, exhibits superior NH3-SCR activity and extraordinary hydrothermal stability (steaming at 800 °C for 16 h), implying its promising application for NOx removal. In addition, high-silica SSZ-13 shows good catalytic performance for the MTO reaction. It is anticipated that the embryonic zeolite-assisted strategy will benefit the synthesis of more industrially important zeolites.
研究领域:
材料科学
·
催化化学
✓ 已验证
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
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Minghu Zhao,Junyi Chen,Fei Wu,Yungang Wang,Kai Chen,Chao Xiong,Rongshu Zhu
Rationally designing catalysts suitable for flue gas purification at low temperatures and unraveling the anti-poisoning mechanism at the atomic level remain challenges. Here, a highly dispersed Ni-doped MnO x catalyst (Ni 0.1 Mn 0.9 O x ) was constructed and applied for selective catalytic reduction (SCR) of nitrogen oxides (NO x ). The long-term stability of Ni 0.1 Mn 0.9 O x is up to 80% (180 ℃) after 18 h under SO 2 and H 2 O conditions. This is due to the fact that the highly dispersed Ni atoms enhance the redox and surface acidity of MnO x , and modulate the electronic structure of the active Mn sites. The denitrification reaction on Ni 0.1 Mn 0.9 O x mainly follows the Eley-Rideal mechanism. The anti-poisoning mechanism is that the introduction of Ni weakens the electron transfer between the Mn site and SO 2 , thereby inhibiting the adsorption of SO 2 . In particular, the H 2 O adsorbed on the Ni sites is decomposed to replenish the depleted Brønsted acid sites, which facilitates the adsorption of NH 3 . However, an excess of H 2 O can have an inhibitory effect. In addition, the mesoporous structure may increase the mass transfer rate and reduce the accumulation of harmful substances. This study provides viable insights for the design of SCR catalysts with excellent anti-poisoning ability.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2021
·
IF 6.609
Zhanzhi Ge,Yuesong Shen,Sasa Gu
The catalyst for selective catalytic reduction of NO x at high temperatures is significantly demanded by current gas-fired exhaust purification. In this work, the complex oxides composed of two different structures of ZrO 2 -WO 3 and WO 3 /ZrO 2 with zirconium as the main component were prepared for NH 3 -SCR of NO at high temperatures by blending method and equal volume impregnation method, respectively. Combined with XRD, NH 3 -TPD, FE-SEM, BET and in situ DRIFTS characterization, the effects of component optimization of two kinds of ZrO 2 and WO 3 complex oxides on the performance for NH 3 -SCR of NO were mainly studied. The optimal compatibility of ZrO 2 and WO 3 complex oxides was determined, and the corresponding N 2 selectivity and anti-interference ability of water vapor and SO 2 were further investigated. Results showed that the performance of ZrO 2 -WO 3 prepared by blending method for NH 3 -SCR of NO was significantly better than that of WO 3 /ZrO 2 prepared by impregnation method. The ZrO 2 -WO 3 containing 20% WO 3 has the best performance in NH 3 -SCR of NO with NO conversion higher than 90% and N 2 selectivity higher than 90% at 450–650 °C, and the performance was not affected by SO 2 , slightly affected by competitive adsorption of water vapor at 450 °C and not disturbed by water vapor above 500 °C. Further investigation showed that the NH 3 -SCR of NO over the ZrO 2 -WO 3 reaction followed both L-H and E-R mechanisms. Characterization analysis revealed that ZrO 2 -WO 3 has finer microscopic particles, larger specific surface area, higher acid amount and stronger acid strength than WO 3 /ZrO 2 .
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）