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
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2025
·
IF 5.4
Jian Gao,Xinrui Dai,Zhenhua Gu,Guixian Deng,Jiangyong Yuan,Kongzhai Li
Catalysts loaded with metal oxides of M (M = Mn, Co, Ce) were synthesized by deposition precipitation method using cold rolled sludge (iron oxide as the main component) as a raw material for the selective catalytic reduction of NO x by ammonia (NH 3 -SCR). Among the various formulations, the co-supported catalyst containing 5 % Mn and 5 % Co on CRS-400 exhibited exceptional SCR performance, achieving over 90 % conversion of NO x from 80 °C to 200 °C. The addition of 5 % Mn and 5 % Co as active components resulted in an increase in the specific surface area for catalytic performance and an enhancement of the redox capacity, leading to a significant improvement in catalyst activity. The catalyst’s efficient denitration performance was attributed to the synergistic interaction between Mn, Co, and Fe oxides, resulting in a catalyst with a higher proportion of adsorbed oxygen, as well as an elevated composition of Mn 4+ and Fe 2+ species. The catalyst demonstrated excellent SCR activity at low-temperatures, indicating its potential for downstream applications in soot treatment equipment. This would achieve the dual benefits of purifying the atmosphere and disposing of solid waste.
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 HAZARDOUS MATERIALS
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2020
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IF 9.038
Xuan Liu,Chang’an Wang,Tao Zhu,Qiang Lv,Defu Che
In this paper, the simultaneous removal of SO 2 and NO x catalyzed by Fe-Mo mixed oxides at varying Mo/Fe atomic ratios was reported for the first time with the aim of reducing H 2 O 2 consumption and elucidating the roles of Fe and Mo species in the catalytic process. Fe-Mo mixed oxides with varying Mo/Fe atomic ratios were synthesized and the catalytic performances were systematically studied. The catalyst with Mo/Fe atomic ratio of 2.0 exhibited the highest activity, with which removal efficiencies of 89.4 % for NO x and 100 % for SO 2 can be attained at extremely low H 2 O 2 dosage. Products analysis revealed that SO 2 was mainly removed via wet scrubber, while the adequate oxidation resulting from OH radicals was the prerequisite for NO x removal. The redox pair of Fe 2+ /Fe 3+ played a significant role in decomposing H 2 O 2 , while Mo species had double effect on catalytic activity. Higher Mo content resulted in abundant oxygen vacancies and stronger surface acidity, which favored OH formation. However, the excessive Mo content involved severe surface Mo enrichment and remarkably reduced the active sites of Fe species. The H 2 O 2 /Fe-Mo catalyst system showed excellent stability and had a promising prospect for simultaneously removing SO 2 and NO x in coal-fired flue gas.
研究领域:
环境科学
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催化化学
✓ 已验证
DOI
高影响因子
ChemCatChem
·
2018
·Vol. 10
·期 11
·2481-2487
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IF 4.674
Yani Zhang,Yue Peng,Chizhong Wang,Kezhi Li,Shuai Liu,Xiansheng Li,Jianjun Chen,Junhua Li
Graphical Change for copper : Copper ion exchanged SAPO-47 zeolite catalysts are synthesized and used for the selective catalytic reduction (SCR) of NO x with ammonia, for which they exert high activity. The structure–activity relationship is explored. Copper-exchanged H-SAPO-47 zeolites were synthesized by an aqueous solution ion exchange method and applied in the selective catalytic reduction of NO with NH 3 (SCR). The microporous chabazite (CHA) structure of the catalysts was characterized and confirmed using synchrotron X-ray diffraction and nitrogen adsorption–desorption experiments. The synthesized Cu x -SAPO-47 catalysts exhibited excellent SCR activity and nearly 100 % N 2 selectivity in a wide temperature range. The Cu 0.1 -SAPO-47 sample exhibited higher activity than the other samples below 250 °C. The weak Lewis acid sites originating from the introduction of Cu 2+ were more active than the Brønsted acid sites of the zeolites framework at low temperature. Two types of isolated Cu 2+ species with different coordination surroundings were found, namely, Cu 2+ cations bonded with the six-membered rings and those bonded in the CHA cages. The former species exhibited good stability and activity at high temperature, whereas the latter ones were more active at low temperature. The Cu 0.1 -SAPO-47 catalyst provided a considerable amount of isolated Cu 2+ bonded in the CHA cages. These results indicated that active Lewis acid sites and isolated Cu 2+ species are responsible for their excellent SCR activity.
研究领域:
化学工程
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催化材料科学
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DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2019
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IF 6.393
Rui Gao,Shan Gao,Ping Wang,Yingming Xu,Xianfa Zhang,Xiaoli Cheng,Xin Zhou,Zoltán Major,Hanyue Zhu,Lihua Huo
Ionic liquid [Bmim][BF 4 ] is used as a templating agent to synthesize ZnO with snowflake morphology by hydrothermal method. Different calcination temperatures make snowflake ZnO retain different content of ionic liquid residual which results in different gas response. The mesoporous ZnO material obtained after calcination at 650 °C shows the best gas response to NO x . The sensor not only has excellent gas selectivity, but also exhibits an optimal response to NO x (S = 73.4) at 170 °C with a response range of 0.05 ∼ 10 ppm. In addition, the sensor has good repeatability and long-term stability and also exhibits good moisture resistance at different humidity levels which may be attributed to an appropriate amount of residual ionic liquid after high temperature calcination. The reaction mechanism of the sensor to NO x is also discussed in detail based on XPS analysis, GC–MS measurement and DFT calculations.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Sensors
·
2023
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IF 8.9
Shiyuan Xu,Xuemei Liu,Jiaying Wu,Jianmin Wu
The detection of nitric oxide in human exhaled breath (EB) has received wide attention due to its close relationship with respiratory tract inflammation. Herein, a ppb-level NOx chemiresistive sensor was prepared by assembling graphene oxide (GO) with a conductive π–d conjugated metal–organic framework Co3(HITP)2 (HITP = 2,3,6,7,10,11-hexaiminotriphenylene) in the presence of poly(dimethyldiallylammonium chloride) (PDDA). The construction of a gas sensor chip was achieved by drop-casting the GO/PDDA/Co3(HITP)2 composite onto ITO-PET interdigital electrodes, followed by in situ reduction of GO to reduced graphene oxide (rGO) in hydrazine hydrate vapor. Compared with bare rGO, the nanocomposite shows significantly improved sensitivity and selectivity for NOx among various gas analytes owing to its folded and porous structure as well as its numerous active sites. The limit of detection (LOD) for NO and NO2 can reach as low as 11.2 and 6.8 ppb, respectively, and the response/recovery time to 200 ppb NO is 24/41 s. These results indicate that rGO/PDDA/Co3(HITP)2 can achieve a sensitive and fast response toward NOx at room temperature (RT). Additionally, good repeatability and long-term stability were observed. Furthermore, the sensor shows improved humidity tolerance owing to the presence of hydrophobic benzene rings in Co3(HITP)2. To demonstrate its ability in EB detection, EB samples collected from healthy individuals were spiked with a certain amount of NO to simulate the EB of respiratory inflammatory patients. The sensor can successfully distinguish healthy people from the simulated patients. Furthermore, in real clinical sample detection, the sensor can further differentiate acute respiratory inflammatory patients from the chronic ones.
研究领域:
材料科学
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医学诊断
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传感技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2018
·Vol. 34
·期 4
·661-664
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IF 1.248
Yi Ting,Li Jingwei,Zhang Yibo,Yang Xiangguang
Hollow-ZSM-5 was synthesized by a traditional hydrothermal method without alcohol, and a novel na-no-sized Ce-Cu/hollow ZSM-5 sample was prepared by conventional incipient wetness impreganation. The catalysts were characterized by TEM, SEM, XRD, NMR and N 2 adsorption-desorption. The results indicate that the hollow-ZSM-5 has a good MFI structure with large surface area. The synthesized CeO 2 -CuO/hollow ZSM-5 showed an excellent catalytic activity for NO x conversion(90% NO x conversion were obtained) in the temperature range of 340–550 °C under GHSV=480000 mL·g ‒1 ·h ‒1 due to its appropriate redox ability and acidity.
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
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2025
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IF 11.3
Zhiqiang Zhang,Baiyun Zhu,Lu Xu,Yan Wang,Jiawei Ji,Wang Song,Meilin Tao,Changjin Tang,Lin Dong
Alkali metal poisoning represents a formidable challenge for the effective utilization of ammonia selective catalytic reduction (NH3–SCR) technology. Herein, we propose a versatile strategy to radically circumvent the deactivation effect from alkali metals via regulated activation of surface NOx species. Activity test showed that after physical mixing with a series of zeolites (ZSM-5, MOR, and SAPO-34), the activity of the K-poisoned CeO2–MnOx catalyst achieved complete recovery, and the observed NO conversion was found to be even superior to that of the fresh catalyst. Mechanism analysis from in situ DRIFTS and TPSR revealed that K deposition shut off the transformation of surface NOx from chelating bidentate nitrites to bidentate nitrates (both bridging and chelating bidentate nitrates), leading to catalyst deactivation. Zeolite coupling introduced labile NO+ species, which interacted facilely with the chelating bidentate nitrites to generate chemically reactive bidentate nitrates, enabling a thorough regeneration of NH3–SCR performance. In addition to CeO2–MnOx, this strategy was also found to be valid for a variety of NH3–SCR catalysts, demonstrating great potential in reversing alkali metal poisoning.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Sciences
·
2024
·
IF 5.9
Yingqi Zhao,Zhaoyan Zhang,Ya Zhao,Chong Wang,Hua Xie,Jiayue Yang,Weiqing Zhang,Guorong Wu,Gang Li,Ling Jiang,Xueming Yang
It is highly challenging to precisely compare the impacts of anthropogenic pollutants on the photooxidation of isomeric volatile organic compounds with respect to molecular compositions and particle number/mass concentrations of secondary organic aerosols (SOAs). In this study, we conducted a series of well-defined indoor chamber experiments to compare the effects of NO x (NO and NO 2 ) on the photooxidation of isomeric monoterpenes of β -pinene and limonene. For the photooxidation of β -pinene with NO x , the increase of the initial concentrations of NO ([NO] 0 ) shows a monotonous suppression of the particle mass concentration, whereas the increase of [NO 2 ] 0 shows a monotonous enhancement of the particle mass concentration. For the photooxidation of limonene with NO x , the increase of [NO] 0 exhibits a monotonous suppression of the particle mass concentration, whereas the increase of [NO 2 ] 0 shows a parabolic trend of the particle mass concentration. Utilizing a newly developed vacuum ultraviolet free electron laser (VUV-FEL), the online threshold photoionization mass spectrometry reveals a series of novel compounds at molecular weight (MW) = 232 and 306 for the β -pinene + NO x system and MW = 187, 261, 280, and 306 for the limonene + NO x system. The molecular structures and formation pathways of these species were inferred, which led to the prediction of the diversity and difference of SOA products (i.e., ester and peroxide accretion products) formed from different monoterpene precursors. To improve the predictions of future air quality, it is recommended that climate models should incorporate the NO x -driven diurnal photooxidation of monoterpenes for SOA formation mechanisms.
研究领域:
大气化学
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环境科学
✓ 已验证
DOI
高影响因子
Journal of Environmental Sciences
·
2022
·
IF 6.796
Peng Lu,Xianhui Yan,Lyumeng Ye,Dingsheng Chen,Dongyao Chen,Jianhang Huang,Chaoping Cen
The co-removal of CO 2 while removing SO 2 and NO x from industrial flue gas has great potential of carbon emission reduction but related research is lacking. In this study, a wet scrubbing process with various urea solutions for desulfurization and denitrification was explored for the possibility of CO 2 absorption. The results showed that the urea-additive solutions were efficient for NO x and SO 2 abatement, but delivered < 10% CO 2 absorption efficiency. The addition of Ca(OH) 2 dramatically enhanced the CO 2 absorption, remained the desulfurization efficiency, unfortunately restricted the denitrification efficiency. Among various operating parameters, pH of solution played a determining role during the absorption. The contradictory pH demands of CO 2 absorption and denitrification were observed and discussed in detail. A higher pH of solution than 10 was favorable for CO 2 absorption, while the oxidizing of NO to NO 2 , NO 2 − or NO 3 − by NaClO 2 was inhibited in this condition. When 7 < pH < 10, it was favorable for the conversion and absorption of NO and NO x . However, the conversion of HCO 3 − to CO 3 2− was significantly inhibited, hence preventing the absorption of CO 2 . Large part of Ca(OH) 2 became CaCO 3 with a finer particle size, which covered the unreacted Ca(OH) 2 surface after the reaction. Kinetic analysis showed that the CO 2 absorption in urea-NaClO 2 -Ca(OH) 2 absorbent was controlled by chemical reaction in early stage, then by ash layer diffusion in later stage.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Catalysis
·
2021
·
IF 13.084
Dongdong Chen,Huarong Lei,Wuwan Xiong,Ying Li,Xiang Ji,Jia-Yue Yang,Baoxiang Peng,Mingli Fu,Peirong Chen,Daiqi Ye
Phosphorus (P) originating from lubricant oil additives or biofuels is an emerging chemical poison in catalytic systems for automotive exhaust after-treatment. Here, we demonstrate that P-poisoning led to severe deactivation of small-pore Pd-SSZ-13 zeolites (with CHA framework) as passive NOx adsorbers (PNA) and CO oxidation catalysts for cold-start exhaust purification applications. Deactivation mechanisms of P-poisoning were unraveled by comparatively examining the P-free and P-loaded Pd-SSZ-13 zeolites using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance (NMR), temperature-programmed reduction by hydrogen (H2-TPR), CO pulse adsorption, temperature-programmed desorption using NH3 as a probe molecule (NH3-TPD), ultraviolet/visible light (UV/vis) spectroscopy, and in situ diffuse relectance infrared Fourier transform spectroscopy (DRIFTS). The loss of isolated Pd sites─namely, [Pd(OH)]+ and Pd2+ (located in the eight- and six-membered rings of CHA framework, respectively)─was revealed to be largely responsible for the deactivation of Pd-SSZ-13 in passive NOx adsorption and catalytic CO oxidation. In situ DRIFTS studies using NO or CO as a probe molecule suggest that [Pd(OH)]+ was more susceptible to P-poisoning than Pd2+. Specifically, P-poisoning led to a migration of [Pd(OH)]+ from cationic exchange sites to the zeolite surface, forming inactive metaphosphate (i.e., [Pd(OH)]+PO3–) and bulk PdOx species at high temperatures. In contrast, P-poisoning of Pd2+ sites proceeded via a sequential transformation to [Pd(OH)]+ first, and then to [Pd(OH)]+PO3– and bulk PdOx. This study provides a comprehensive mechanistic understanding on the deactivation of Pd-SSZ-13 by P-poisoning, and may guide the design of high-performance, phosphorus-resistant Pd-zeolite catalysts for cold-start exhaust after-treatment.
研究领域:
催化材料
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环境科学
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化学工程
✓ 已验证
DOI
高影响因子
ChemCatChem
·
2022
·Vol. 14
·期 17
·e202200476
·
IF 5.497
Shuangxi Li,Weiwei Hu,Ziqiang Xu,Huijun Yu,Tianwei Lan,Lupeng Han,Dengsong Zhang
Graphical Reaction pathway ? More adsorption of NH 3 /NH 4 + species and the higher reactivity with gaseous NO maintain the process of E−R reaction path, leading to a satisfactory SCR activity of K poisoned NbFeVO x /TiO 2 . Whereas the decreased adsorption and reactivity of NH 3 /NH 4 + and NO x restrains the process of L−H reaction path, thus showing inferior SCR activity of K poisoned FeVO 4 /TiO 2 . FeVO 4 -based catalysts with a wide temperature window and high SO 2 tolerance have attracted increasing attention for the selective catalytic reduction of NO x with NH 3 . However, the alkali-resistance of FeVO 4 -based catalysts is still challenging. In this study, the K-resistance of FeVO 4 /TiO 2 was markedly improved via the Nb modification. It was demonstrated that the adsorption and reactivity of NH 3 /NH 4 + and NO x species on K poisoned FeVO 4 /TiO 2 both decreased, which restrained the process of Langmuir-Hinshelwood reaction path. As a comparison, more adsorption of NH 3 /NH 4 + species and the higher reactivity with gaseous NO maintain the process of Eley-Rideal reaction path, leading to a satisifactory SCR activity. This work demonstrated an effective route to improve alkali-resistance via modulating reactivity and reaction path of adsorbed NH 3 /NH 4 + and NO x species over Nb modified vanadate catalysts, which presented a new point for the development of high-performance alkali-resistant SCR catalysts.
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
危险品化学品经营许可证（带存储）