Materials
·
2021
·Vol. 14
·期 20
·5958
·
IF 3.623
Xusheng Ren,Zhiliang Ou,Bang Wu
The activated coke is a promising support for catalysts, and it is important to study the performance of the activated coke catalyst on the removal of NOx. In the current research, a series of the activated coke-supported Mn–Cu catalysts are prepared by the incipient wetness impregnation method. The effects of the molar ration of Mn/Cu, the content of Mn–Cu, the calcination temperature, and reaction space velocity on NO conversion are investigated, and it was found that the 8 wt.% Mn0.7Cu0.3/AC had the best catalytic activity when the calcination temperature was 200 °C. The existence of SO2caused the catalyst to deactivate, but the activity of the poisoning catalyst could be recovered by different regeneration methods. To uncover the underlying mechanism, BET, XPS, XRD, SEM and FTIR characterizations were performed. These results suggested that the specific surface area and total pore volume of the poisoning catalyst are recovered and the sulfite and sulfate on the surface of the poisoning catalysts are removed after water washing regeneration. More importantly, the water washing regeneration returns the value of Mn3+/Mn4+, Cu2+/Cu+, and Oα/Oβ, related to the activity, basically back to the level of the fresh catalyst. Thus, the effect of water washing regeneration is better than thermal regeneration. These results could provide some helpful information for the design and development of the SCR catalysts.Keywords:activated coke;low-temperature NH3-SCR;sulfur poisoning;regeneration
研究领域:
催化化学
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环境科学
✓ 已验证
DOI
PubMed
高影响因子
ENERGY & FUELS
·
2017
·
IF 3.091
Linlin Yi,Huan Liu,Geng Lu,Qiang Zhang,Jiaxing Wang,Hongyun Hu,Hong Yao
Considerable amounts of NOx are generated from the thermal utilization of solid wastes. To control NOx emission, we investigated the influence of mixed Fe/Ca additives on the generation of NOx precursors (HCN and NH3) during pyrolysis at 873, 1073, and 1273 K. Protein, proline, and phenylalanine were selected as model compounds to represent the primary nitrogen forms in typical solid wastes, such as biomass and sludge. According to the results, the iron effect is a remarkable property that enables the obvious reduction of NH3. This was most likely because NH3 was consumed by iron compounds to generate FeNx. Iron compounds facilitated thermal cracking of heterocyclic N with the release of HCN. Ca(OH)2 promoted the conversion of HCN to NH3 and fixed HCN to form CaCxNy simultaneously. These intermediates (FeNx and CaCxNy) play important roles in the reduction of NOx precursors. A lower emission of NOx precursors was observed with mixed Fe/Ca additives than with either Fe or Ca individually. This is because the generation of Ca2Fe2O5 enhanced the tranformation of intermediates to N2. The transformation of intermediates to N2 was enhanced at elevated temperatures, which allows for the lowest emission of precursors (NH3 and HCN) at 1273 K, with a higher ratio of Ca2Fe2O5 in char.
研究领域:
环境科学
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化学工程
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Wenqi Liu,Jingyan Zhang,Mei Dong,Zhaoyi Ding,Qunfei Wang,Fanghao Ning,Qin He,Yanyan Chen,Zhen Zhao,Zhongfu Li,Conghua Liu
Low-silica chabazite (CHA) catalysts with varying configurations of Cu 2+ -2Z and [Cu(OH)] + -Z active centers are developed through the regulation of the opening of CHA-cages. The catalysts are subsequently applied to the selective catalytic reduction of NO x by NH 3 (NH 3 -SCR) reactions. A series of characterizations and performance evaluations indicate that the density of [Cu(OH)] + -Z in eight-member rings (8MRs) is positively correlated with low-temperature performance. Moreover, the presence of partial Cu 2+ -2Z in six-member rings (6MRs) enhances activity and tolerance at high temperatures. The residual K + ions in the CHA-cages after NH 4 + exchange are retained in the 6MRs. Density functional theory calculations demonstrate that the residual K + ions stabilize the 6MRs structure, ensuring the entry and stable presence of the active Cu 2+ -2Z centers. In situ analysis reveals the reaction intermediates involved in the NH 3 -SCR process on representative catalysts. These findings can further elucidate the active centers of CHA-type catalysts and guide the design of commercial 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
·
2021
·
IF 5.909
Zhifei Hao,Guoquan Liu,Nan Ma,He Zhang,Yi Li,Yuguo Xia,Dongpeng Zhang,Sihui Zhan
Acidity and redox properties of the catalyst are two crucial factors affecting the performance of NH 3 -SCR. Herein, we design a novel WO x /Cu-CeO 2 oxide catalyst in which the WO x species are highly dispersed on the {111}/{100}-terminated surface of Cu-doped CeO 2 nanospheres , which exhibits great deNO x activity advantage and wide operating temperature window (200–400 °C, over 85% NO x conversion with a gas hourly space velocity (GHSV) of 60,000 h −1 ), as well as good sulfur resistance and N 2 selectivity . The relationship among the composition, acidity and redox properties of the WO x /Cu-CeO 2 catalyst is established in the NH 3 -SCR reaction. The combined experimental studies and spectroscopic characterization reveal that the introduction of Cu into the lattice of CeO 2 not only increases the surface Ce 3+ and oxygen vacancy concentration but also provides more sites for capture and dispersion of WO x species, thus mediating and improving the Lewis and Brønsted acid sites and reducibility of catalyst. XPS and DFT calculations further demonstrate that electronic interaction between WO x and Cu-doped CeO 2 is enhanced duo to the existence of interactions of short-range Ce-O-Cu and Ce-O-W. Moreover, the NH 3 -SCR reaction over WO x /Cu-CeO 2 may follow both Langmuir-Hinshelwood and Eley-Rideal reaction pathway according to the 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
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 43
·20777-20785
·
IF 3.925
Yanke Yu,Mengqiao Geng,Desheng Wei,Chi He
Selective catalytic oxidation of NH3 (NH3-SCO) is a promising method to reduce NH3 pollution. The Pt-based catalysts exhibited excellent activity in the NH3-SCO reaction under low temperatures. However, it was easy for the NH3 to be oxidized to N2O and NOx (NO and NO2) over the Pt-based catalyst, causing a low N2 selectivity. The CuSO4, which could supply both Brønsted and Lewis acid sites on the catalyst, was used to promote N2 selectivity. The N2 adsorption–desorption, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), inductively coupled plasma mass spectrometry (ICP-MS), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), NH3-temperature programmed desorption (NH3-TPD), H2-temperature programmed reduction (H2-TPR) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) were used to characterize the catalyst. The addition of CuSO4 could suppress the formation of N2O and NOx, thus the highest N2 selectivity on the catalyst increased from 21.2% to 78.1%. An imide mechanism was the main reaction mechanism on the Pt/TiO2 catalyst. After adding CuSO4, the NH3-SCO reaction over the CuSO4-Pt/TiO2 catalyst mainly followed an i-SCR mechanism where NH3 was oxidized to N2O and NOx, and then the newly formed N2O and NOx were reacted with NH3/NH4+ adsorbed on the Lewis and Brønsted acid sites via an NH3-SCR reaction over the catalyst, and finally N2 was formed. The acid sites performed an important role in the formation of N2 and this work should provide an effective method to promote N2 selectivity in a NH3-SCO reaction.
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 MOLECULAR LIQUIDS
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2020
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IF 5.065
Dongshun Deng,Xiaoxia Deng,Xiuzhi Duan,Lei Gong
Deep eutectic solvents (DES) are regarded as the second generation ionic liquids with potential application in gas capture and separation field due to negligible vapor pressure and abundant formation variation. In present work, protic guanidine isothiocyanate was selected as hydrogen bond acceptor and paired with acetamide as hydrgen bond donor to construct low viscosity DES. The DESs were characterized with phycsichemical properties and utilized in NH 3 capture and NH 3 /CO 2 separation systematically. The gas solubility enhcanced with the increasing molar ratio of GI to AT, increasing pressure, and falling temperature. The solubilities of NH 3 and CO 2 were correlated by Henry's law . The thermodynamic parameters were further calculated according to the temperature dependence of Henry's constants . The NH 3 saturated DES could be easily recycled five times with persistent absorption performance. The ideal NH 3 /CO 2 selectivity at 303.15 K was 151 and higher than most solvents reported in the literatures. The absorption mechanism was further deduced by NMR and F-IR spectroscopy. These DESs presented efficient NH 3 absorption and selective separation performance due to good absorption performance, reversibility, and high NH 3 /CO 2 selectivity.
✓ 已验证
DOI
高影响因子
Surfaces and Interfaces
·
2025
·
IF 6.3
Huiying Li,Zhixing Gao,Xinyue Yang,Chen Zhang,Zhongjie Du,Wei Zou
To meet the growing demands for ammonia gas (NH 3 ) sensor, the development of high-performance sensing materials is essential. Herein, the polyaniline (PANI) pristine hollow microspheres (H-PANI) with high specific surface area were prepared through template removal approach, and then exhibited an enhancing NH 3 detection performance than PANI powders. Firstly, polyaniline core-shell hollow microspheres (PANI-TEMs) were prepared by in-situ oxidative polymerization of aniline onto the surface of thermally expandable microspheres (TEMs) template. Subsequently, H-PANI featuring a dense shell and a high specific surface area of 72.35 m 2 /g was obtained after the removal of the TEMs template. Based on the results of the morphology and the specific surface area of the hollow microspheres characterized by scanning electron microscopy (SEM) and N 2 adsorption-desorption technique, respectively, the preparation of PANI-TEMs and the removal process were investigated and optimized. Finally, when the obtained H-PANI was employed in NH 3 detection, according to the ratio of the changed resistance to the initial resistance, the sensitive response values of up to 144 for 3000 ppm NH 3 and 8 for 50 ppm NH 3 at room temperature were achieved, which could attribute to the increased specific surface area. This finding holds great potential for enhancing the sensitivity of ammonia detection materials.
研究领域:
材料科学
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化学工程
·
传感技术
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2024
·Vol. 53
·期 29
·12291-12300
·
IF 3.5
Liangliang Huang,Tao Peng,Rui Wang,Beibei He,Jun Jin,Huanwen Wang,Yansheng Gong
Photocatalytic ammonia production holds immense promise as an environmentally sustainable approach to nitrogen fixation. In this study, In2O3/In2S3-ZnCdS ternary heterostructures were successfully constructed through an innovative in situ anion exchange process, coupled with a low-temperature hydrothermal method for ZnCdS (ZCS) incorporation. The resulting In2O3/In2S3-ZCS photocatalyst was proved to be highly efficient in converting N2 to NH3 under mild conditions, eliminating the need for sacrificial agents or precious metal catalysts. Notably, the NH4+ yield of In2O3/In2S3-0.5ZCS reached a significant level of 71.2 μmol g−1 h−1, which was 10.47 times higher than that of In2O3 (6.8 μmol g−1 h−1) and 3.22 times higher than that of In2O3/In2S3 (22.1 μmol g−1 h−1). This outstanding performance can be attributed to the ternary heterojunction configuration, which significantly extends the lifetime of photogenerated carriers and enhances the spatial separation of electrons and holes. The synergistic interplay between CdZnS, In2S3, and In2O3 in the heterojunction facilitates electron transport, thereby boosting the rate of the photocatalytic nitrogen fixation reaction. Our study not only validates the efficacy of ternary heterojunctions in photocatalytic nitrogen fixation but also offers valuable insights for the design and construction of such catalysts for future applications.
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
PubMed
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2023
·
IF 5.7
Tao Zhang,Guiqing Zhang,Zuoying Cao,Mingyu Wang,Wenjuan Guan,Shengxi Wu,Qinggang Li
Background The NH 3 , a clean reductant, generated by the thermolysis of NH 4 VO 3 , is not effectively utilized in the conventional process of vanadium metallurgy. Additionally, the preparation process of V 2 O 3 is both long and costly. Ammonia recovery is essential to prevent environmental issues resulting from ammonia release. By direct thermolysis of NH 4 VO 3 and effectively utilizing of active NH 3 , it is possible to achieve the short flow and green process for the production of V 2 O 3 . Method In an open NH 3 atmosphere, one end of the flange was connected to the liquid ammonia gas cylinder, while the other end was connected to the tail gas absorber. Furthermore, in a closed NH 3 atmosphere, both ends of the tube furnace were sealed with flanges, and the initial atmosphere in the tube was pre-injection NH 3 . The products of NH 4 VO 3 thermolysis were characterized using various techniques, including XRD, FT-IR, ICP-OES, SEM, XPS, and TG. Significant finding The thermolysis process of NH 4 VO 3 with pre-injection of NH 3 under the sealed condition was a simulation of the continuous production process of V 2 O 3 using a rotary kiln in industrial production. The rational utilization of ammonia resulted in the reduce of energy consumption, extra reductant consumption, and significant NH 3 emissions compared to the traditional V 2 O 3 production process. It was observed that V 2 O 3 was easily obtained through the thermolysis of NH 4 VO 3 with pre-injection of NH 3 under the sealed condition at 600 °C for 3 h, using a dosage of NH 4 VO 3 ranging from 2 g to 10 g. During this process, the NH 4 VO 3 went through the phase transition as follows: NH 4 VO 3 →NH 4 V 3 O 8 →(NH 4 ) 0.38 V 2 O 5 →V 6 O 13 →VO 2 →V 4 O 7 →V 3 O 5 →V 2 O 3 , and the relevant characterization of products showed that the V 2 O 3 obtained was qualified. These experimental results were of great significance to the industrial practice of vanadium metallurgy. Based on these results, short flow and green process of V 2 O 3 could be achieved in industry by partially improving the calcination process of NH 4 VO 3 in large-scale rotary kilns.
研究领域:
冶金学
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材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Jiangxiao Qiao,Jinxin Gan,Fei Gao,Xiangsen Xu,Jiesong Tan,Yiqing Zeng,Feng Zhang,Feng Han,Zhaoxiang Zhong,Weihong Xing
Synergistic removal of nitrogen oxides (NOx) and particulate matter (PM) can be achieved using multifunctional catalytic membranes. In this work, CePO4 nanorods were loaded on the pore surfaces of SiC membranes to construct the CePO4/SiC-X catalytic membranes. The stacked nanorod structure of the CePO4 catalyst layer facilitates the diffusion of gases to the catalyst surface during reactions. Owing to the high specific surface area, rich surface acidity, and strong redox capacity, the CePO4/SiC-400 catalytic membrane exhibits the best ammonia-selective catalytic reduction (NH3–SCR) denitration activity, achieving >90% NO conversion at a temperature of 250–380 °C and negligible N2O byproduct. In addition, the CePO4/SiC-400 catalytic membrane demonstrates excellent H2O and SO2 resistance. The performance of dust filtration and simultaneous dust filtration and denitration at 250–350 °C proposed that the dust rejection efficiency reached more than 99% at various conditions, and the dust filtration process did not affect the NH3–SCR performance of the CePO4/SiC-400 catalytic membrane. From the above results, the CePO4/SiC-400 catalytic membrane presents a broad application prospect in the simultaneous dust removal and denitration of high-temperature flue gas.
研究领域:
环境科学
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催化材料
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Jiahao Chen,Bin Wang,Kai Yuan,Yutang Kang,Shasha Feng,Feng Han,Hongmiao Wu,Rongfei Zhou,Zhaoxiang Zhong,Yiqun Fan,Weihong Xing
The SiC catalytic membrane combining dust removal and denitration can realize the efficacious treatment of atmospheric pollutants. Unfortunately, a large amount of SiO 2 , formed by the partial oxidation of SiC at a high temperature, results in the decreased chemical resistance of SiC catalytic membrane. In addition, the complicated preparation processes and susceptible to loss of catalytic components under harsh conditions restrict the industrial application of SiC catalytic membranes. Here, the Cu-SAPO-34(D)/SiC catalytic membranes were directly prepared via a facile one-pot hydrothermal synthesis method, which ingeniously utilized the generated SiO 2 as a Si source to participate in the growth of Cu-SAPO-34 zeolites. Excellent binding strength and chemical resistance were simultaneously realized for the SiC catalytic membranes. As a comparison, a Cu-SAPO-34(I)/SiC catalytic membrane was fabricated via the conventional two-step ion-exchange method. The 0.2 Cu-SAPO-34(D)/SiC (Cu molar ratio of 0.2) achieved the best NH 3 -SCR performance among the prepared catalytic membranes for its highly active copper and oxygen species, abundant Lewis acid sites and remarkable redox capacity. When implementing the simultaneous removal of NO and PM, the 0.2 Cu-SAPO-34(D)/SiC catalytic membrane achieved a high NO degradation performance of 98% from 200 to 280 °C, coupled with an excellent PM 0.3 (model dust with average size of 300 nm) filtration performance of 99.99%. These results were better than those of the Cu-SAPO-34(I)/SiC catalytic membrane (92% for NO degradation and 99.98% for PM 0.3 filtration). The one-pot in situ synthesis of Cu-SAPO-34(D)/SiC catalytic membrane with enhanced binding strength and chemical resistance provides a novel strategy for preparation of high-performance SiC catalytic membrane with double benefits.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Jingang Wang,Jianbo Zhang,Cheng Xing,Taosheng Jin,Jinpeng Liu,Meiting Ju,Xuejiao Tang
Phosphorus (P) poisoning of NH 3 -SCR catalysts is inevitable in application of NO x abatement of diesel exhaust. The distinct effects on Cu-SSZ-13 of P from different precursors (H 3 PO 4 and (NH 4 ) 2 HPO 4 ) were figured out and the mechanism was further investigated. P-poisoned Cu-SSZ-13 (Si/Al = 6) catalysts were prepared and characterized using N 2 adsorption, X-ray powder diffraction (XRD), scanning electron microscope with energy-dispersive X-ray spectroscopy mapping (SEM-EDX), ammonia temperature-programmed desorption (NH 3 -TPD), X-ray photoelectron spectroscopy (XPS), hydrogen temperature programmed reduction (H 2 -TPR), electron paramagnetic resonance (EPR) and 27 Al solid-state magic angle spinning nuclear magnetic resonance spectroscopies ( 27 Al NMR). Significant enhancement of high-temperature activities (400–600 °C) were observed for the catalysts with P loading of 0.3–0.9 wt%, since the appropriate incorporation enabled to bind P atoms to CuO x in remained framework. However, the high P content of 1.5 wt% resulted in a detrimental effect on framework to induce the accumulation of Cu species. Interestingly, the dominant P from H 3 PO 4 was inclined to directly attack the framework Al leading to more severe dealumination, while the P from (NH 4 ) 2 HPO 4 interacted with Cu 2+ to form copper phosphate with more Cu 2+ migrating to the surface of the catalyst which promoted the NO x conversation at each active site resulting in the low-temperature catalytic activity unchanged. So, control of the P/Cu and form of P is capable of preventing P poisoning and unlocks the potential of Cu-SSZ-13 in exhaust treatment.
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）