CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Xuesong Liu,Peng Jiang,Yong Chen,Yaoguang Wang,Qiaoling Ding,Zhiming Sui,Hongfeng Chen,Zhongyun Shen,Xiaodong Wu
Two Ce-W-Ti mixed oxide catalysts were prepared by wet impregnation (CeW/Ti-I) and mechanical mixing (Ce/W/Ti-M) methods. CeW/Ti-I catalyst exhibits over 80% NO x conversion and nearly 100% N 2 selectivity at 200–550 °C. The superior catalytic performance is associated with the high dispersion of active CeO 2 and acidic WO 3 on TiO 2 and the synergistic effects among different components. The X-ray Diffraction, Raman spectroscopy, Nitrogen physisorption, X-ray photoelectron spectroscopy, H 2 temperature-programmed reduction, temperature-programmed desorption of ammonia and infrared spectroscopy were performed. It is found that the formation of solid solutions, as well as the high specific surface area, would increase the amounts of Ce 3+ , oxygen vacancies and acid sites in the catalyst. These broaden the operating temperature window of NH 3 -SCR reaction and enhance the N 2 selectivity by facilitating “fast SCR” reaction at low temperatures and inhibiting the unselective oxidation of NH 3 at high temperatures.
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
CATALYSIS TODAY
·
2024
·
IF 5.2
Xin Xu,Bolin Xia,Amirreza Gholivand,Xiaoyu Zhang,Yunpeng Zhang,Linhui Liu,Daiqi Ye,Peirong Chen
Selective dissolution is highly promising for tailoring the structures and functions of metal oxides toward various applications. Here, we demonstrate a successful fabrication of porous γ-MnO 2 by selectively dissolving Ca in a CaMnO 3 perovskite (CMO) via dilute HNO 3 treatment. The perovskite-derived γ-MnO 2 (denoted as CMO-72 h) outperformed drastically the pristine CaMnO 3 and a commercial γ-MnO 2 in the catalytic oxidation of NH 3 and NO, two representative gaseous pollutants in the atmosphere. Physicochemical characterization by X-ray photoelectron spectroscopy and temperature-programmed techniques (including H 2 -TPR, O 2 -TPD and NH 3 -TPD) suggests that the excellent catalytic performance of CMO-72 h is associated with its low–temperature reducibility and abundant surface–active oxygen species. Specifically, acid treatment led to the oxidation of Mn 3+ to Mn 4+ on the surface, increasing significantly the Mn 4+ /Mn 3+ ratio from 0.76 (for CMO) to 1.45 (for CMO-72 h) and, meanwhile, generating additional surface oxygen vacancies . As a result, O 2 molecules can be easily adsorbed and activated on the CMO-72 h, leading to improved performance in NH 3 and NO oxidation. This study may offer new opportunities in the synthesis of high-performance Mn oxide catalysts for environmental applications.
研究领域:
环境科学
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材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2022
·
IF 9.221
Yu Zhang,Yongguang Liu,Ling Wang,Huizhu Zhou,Weiwei Meng,Yuehua Li,Zhangxing He,Lei Dai
Spinel oxide Zn 2 SnO 4 with cubic structure was synthesized by solid state reaction method. A NH 3 sensor based on mixed potential mechanism were fabricated with 8% yttria stabilized zirconia electrolyte with bi-layered and Zn 2 SnO 4 sensing electrode (SE). The influence of Zn 2 SnO 4 -SE thickness and sintering temperature on the response performance of the sensor was evaluated. The results display that the sensor using Zn 2 SnO 4 -SE with a thickness of 17 µm and sintered at 1100 °C displays better performance, which is closely related to the microstructure of the Zn 2 SnO 4 -SE. The response signals are linearly related to the logarithm of the NH 3 concentrations over the operating temperature range and at 600 °C the sensor shows the highest sensitivity of − 61.8 mV/decade. The cross-sensitivity experiment results show that the cross-sensitivity of the sensor towards CO 2 and H 2 is hardly observed; the NH 3 sensitivity decreases with the increasing of O 2 content to some extent; relative humidity and NO or NO 2 cause serious interference. In order to eliminate NO or NO 2 interference, CuO was chosen to replace Pt as the reference electrode, and the results show that the cross-sensitivity of the sensor to NO or NO 2 was significantly reduced, but the sensitivity slightly decreases. The sensor also shows a relatively good long-term stability. The polarization curve and Tafel plots verify that the sensor complies with mixed potential model.
研究领域:
传感器学
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材料科学
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分析化学
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环境监测
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气体传感
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Yarong Bai,Junping Dong,Yaqin Hou,Yaoping Guo,Yongjin Liu,Yulin Li,Xiaojin Han,Zhanggen Huang
Herein, a series of Co 3 O 4 nanoparticles inlaid in porous carbon (CoO x @PC-T) were successfully prepared via first pyrolysis of ZIF-67 in argon atmosphere at different temperature and then oxidized in 5% O 2 /Ar mixed gas. The as-made samples were employed as catalysts for selective catalytic reduction of NO x with NH 3 at low temperature (100 °C–200 °C). The effect of pyrolysis temperature on the microstructure, textural properties, and chemical properties of CoO x @PC-T were characterized by TG-MS, BET, XRD, SEM, TEM, H 2 -TPR and XPS in detail. Results show that the pyrolysis temperature has a significant effect on the carbonization degree of carbon in ZIF-67, and which in turn affects the exposure and oxidization of cobalt nanoparticles on the catalyst surface. Experiments results show that CoO x @PC-800 display the highest NO x conversion ratio, which is attributed to its higher ratio of Co 3+ /Co 2+ and large specific surface area. Moreover, the stability, H 2 O and SO 2 resistance of CoO x @PC-800 were also studied.
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
高影响因子
Catalysis Science & Technology
·
2016
·Vol. 6
·期 24
·8516-8524
·
IF 5.287
Lei Huang,Kaiwen Zha,Supawadee Namuangruk,Anchalee Junkaew,Xin Zhao,Hongrui Li,Liyi Shi,Dengsong Zhang
Surface engineering of TiO2 is significant in the SCR reaction and worth studying. In a previous study, we found that TiO2 nanosheets (TiO2-NS) with the (001) plane exhibited a much better SCR performance than TiO2 nanoparticles (TiO2-NP) with the (101) plane. In this work, in situ DRIFTS and DFT calculations were applied to address the promotional effect of the (001) plane of TiO2-NS in the SCR reaction. The behavior of adsorption and desorption of NOx and NH3 on the two surfaces was studied. It was found that NH3 adsorbed on both TiO2-NS and TiO2-NP was in the form of NH3(g) on the Lewis acid sites. NOx on TiO2-NP were mainly trans-(NO)2 and N2O4 which were non-reactive. Differently, NO on TiO2-NS was mainly in the form of NO2 which was probably due to the high energy and abundant active oxygen species of the (001) facet. The formed NO2 could trigger the subsequent ‘fast SCR’ reaction thereafter promoting the activity. Therefore, TiO2-NS with more (001) facets had better SCR activity than TiO2-NP with the exposed (101) facet.
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
APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Weiyuan Yao,Xiaoqiang Wang,Yue Liu,Zhongbiao Wu
In this paper, Ce O P material (mainly consisted of CePO 4 ) and TiO 2 supported CeO 2 catalysts were prepared by wet impregnation route for the selective catalytic reduction (SCR) of NO with NH 3 . The SCR activity results had revealed that CeO 2 /Ce O P-0.4 catalyst yielded over than 90% NO conversion within the temperature range of 200–300 °C, whereas the deNO x efficiency of CeO 2 /TiO 2 -0.4 catalyst was less than 30% at 200 °C. After a series of characterization tests, it was found that CeO 2 /Ce O P catalysts were of better dispersion of active phase than CeO 2 /TiO 2 owing to the strong interactions between CeO 2 and surficial Ce O species on Ce O P material. Thus, more active oxygen species could participate in the SCR reaction at low temperature. Furthermore, compared to CeO 2 /TiO 2 sample, the surface acidity was greatly enhanced for CeO 2 /Ce O P catalysts by the introduction of the acidic support, benefiting the adsorption of NH 3 . Both of which were attributed to the main reasons of the promoted SCR performance over CeO 2 /Ce O P catalysts. Moreover, the NO x ad-species on CeO 2 /TiO 2 sample were very stable and could hardly react with adsorbed NH 3 , impeding L-H reaction pathway at low temperature.
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
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
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Chunxue Wang,Zhao Li,Xin Sun,Yuan Li,Lei Shi,Shunzheng Zhao,Kai Li,Ping Ning,Fei Wang
Ag-based catalysts show high activity in NH 3 -selective catalytic oxidation (NH 3 -SCO). The anchoring states of Ag species determines its valence and dispersion, thereby influencing the performance of Ag-based catalysts. Herein, we elucidated that the content and anchoring strength of the hydroxyl (OH) groups on support together affect the anchoring states of Ag. TiO 2 has few OH groups but high anchoring strength, the anchored Ag is in a highly dispersed oxidized state, while the unanchored Ag is aggregated in a metallic state (Ag 0 ), so it presents an unevenly sized dispersion and mainly in oxidized state. SiO 2 has abundant OH groups but weak anchoring, and can excessively agglomerate into large Ag 0 nanoparticles (Ag 0 NPs). Therefore, the introduction of SiO 2 can regulate the anchoring states of Ag on the TiO 2 support, making Ag presents highly dispersed Ag 0 NPs, thus following a reaction mechanism with lower energy barriers and significantly improving the NH 3 -SCO performance.
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
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Jinxiu Zhao,Xuejing Liu,Xiang Ren,Xu Sun,Dongxu Tian,Qin Wei,Dan Wu
Electrochemical N 2 reduction is developing as an appealing carbon-neutral strategy for NH 3 artificial synthesis but seriously influenced by requiring high-efficiency electrocatalysts for the N 2 activation at ambient conditions. Here, we reported that defective-rich ZnS nanoparticles supported on reduced graphene oxide (DR ZnS-rGO) acts as a high-efficiency electrocatalyst for ambient N 2 -to-NH 3 conversion with excellent selectivity. In 0.1 M HCl, such DR ZnS-rGO presents a large NH 3 yield of 51.2 μg h –1 mg cat. –1 (−0.15 V vs . reversible hydrogen electrode, RHE) and a high faradic efficiency of 28.2 % (−0.10 V vs . RHE), as well as high electrochemical and structure stability. Isotopic labelling samples experiments reveal that the synthetic NH 3 directly arise from the supplied N 2 . Density functional theory calculations demonstrated that the engineering S vacancies in DR ZnS-rGO not only provide reaction sites for N 2 -to-NH 3 conversion but activate of N 2 molecules.
研究领域:
材料科学
·
电化学
·
催化
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Engineering
·
2025
·
IF 11.6
Ying Zhu,Jingjing Liu,Guangzhi He,Shaohua Xie,Wenpo Shan,Zhihua Lian,Fudong Liu,Hong He
Catalytic activity and hydrothermal stability are both crucial for the application of the selective catalytic reduction of NO x with NH 3 (NH 3 -SCR catalyst) in diesel vehicles. In this study, a tin (Sn)-modified Ce–Nb mixed-oxide catalyst was synthesized as an NH 3 -SCR catalyst for NO x emission control. After the introduction of Sn, both the NH 3 -SCR activity and the hydrothermal stability of the catalyst were remarkably promoted. Even after hydrothermal aging at 1000 °C, the developed Ce 1 Sn 2 Nb 1 O x catalyst achieved more than 90% NO x conversion at 325–500 °C. Various methods, including N 2 -physisorption, X-ray diffraction, in-situ high-temperature X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray absorption fine-structure spectroscopy, temperature-programmed reduction of hydrogen, temperature-programmed desorption of ammonia, and density functional theory calculations were used to investigate the promotional effects induced by the Sn species. The characterization results showed that the addition of Sn not only promoted the formation of the Ce–Nb active phase but also improved its thermal stability, contributing to the excellent NH 3 -SCR performance and hydrothermal stability. This study provides an excellent sintering-resistance catalyst for the application of diesel engine NO x emission control.
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
ENERGY
·
2024
·
IF 9
Shuai Guo,Yu Wang,Li Yang,Baizhong Sun,Hongwei Qu,Xingcan Li,Deng Zhao
The study used ReaxFF MD (Reactive Force Field Molecular Dynamics) to investigate the migration behavior and mechanisms of nitrogen in the pyrolysis process of biomass, specifically focusing on the effect of the alkali metal potassium on the main nitrogen-containing substance, proteins. This research primarily centers on the conversion mechanisms of nitrogen in the three-phase products (char, tar, and gas) during the pyrolysis of proteins, as well as the impact on NH 3 formation. The findings reveal several key insights: First, the introduction of potassium significantly enhances the cleavage activity of protein macromolecules by promoting the breaking of carbon-carbon and carbon-nitrogen bonds, which accelerates the degradation process of protein molecules and subsequently increases the conversion rate of nitrogen from proteins to the nitrogen in char, tar, and gas. Second, the addition of potassium alters the sources of gaseous nitrogen (gas-N); initially derived mainly from the secondary cracking of tar nitrogen (tar-N), gas-N predominantly originates from the conversion of char nitrogen (char-N) under the influence of potassium. Lastly, the introduction of potassium affects NH 3 production by significantly altering the trend of nitrogen-hydrogen bond variation during the pyrolysis of proteins. This is primarily attributed to potassium's facilitation of dehydration reactions, which disrupt nitrogen-hydrogen bonds during protein pyrolysis. Additionally, it allows NH 3 produced in the later stages of pyrolysis to participate in the formation of other nitrogen-containing compounds, particularly HCN. Potassium also promotes the dehydrogenation of the large number of HCN molecules generated during protein pyrolysis, forming CN radicals that subsequently react with NH 3 to produce new compounds. This is the main reason for the variation in NH 3 yield.
研究领域:
能源与环境科学
·
化学工程
·
计算化学
✓ 已验证
DOI
高影响因子
International Journal of Refrigeration
·
2021
·
IF 3.629
Zhenghao Jin,Shuhong Li,Runfa Zhou,Mengkai Xu,Weixue Jiang,Kai Du
The newly NH 3 – H 2 O – LiBr working fluid can decrease the power wasted in the generator, thus improves the COP of the ammonia absorption refrigeration system. But the applying of NH 3 – H 2 O – LiBr working fluid decreases the ammonia absorption efficiency, so the COP of the system is still unsatisfactory. To further enhance the COP of the NH 3 – H 2 O - LiBr absorption refrigeration system, TiO 2 nanoparticles are added to the NH 3 – H 2 O - LiBr working fluid in this study. And the effects of TiO 2 nanoparticles concentration on the performances of the generator, absorber, evaporator, condenser, and solution heat exchanger are tested in an ARS experimental system. The experimental results indicate that the addition of TiO 2 nanoparticles increases the P g , P e , P a , and P c , meaning that the value of ammonia produced in the generator increases. Therefore, the COP and iCOP of the system are improved by adding TiO 2 nanoparticles, and the COP is maximum improved by 18.96% compared with the ammonia-water absorption refrigeration system. When the x TiO2 is increased from 0.3% to 0.5%, the increase rate of the COP decreases because the newly added nanoparticles do not disperse well. So 0.3% is a better choice for the TiO 2 nanoparticles concentration when comprehensively considering the dispersion stability of nanoparticles and the COP.
研究领域:
工程热物理
·
制冷技术
✓ 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）