COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
·
IF 4.9
Tian Gu,Chengzhi Wang,Denghui Chen,Mengmeng Han
Modulating the physicochemical properties of catalysts through the construction of special crystal structures or microscopic morphology provides new insights for developing high-performance low-temperature denitrification catalysts. This paper explores the effect of morphology structure on catalyst performance and identifies the dominant driving factors. The catalyst activity sequence was found to be MnO x spiny nanospheres (Mn-SNS) > MnO x nanowires (Mn-N) > MnO x nanospheres (Mn-NS) > MnO x nanoparticles (Mn-P). Among these, the Mn-SNS catalyst prepared by the hydrothermal method exhibited the best catalytic activity and the good resistance to water and sulfur. It achieved over 70% NO x conversion at 150 °C, and maintained 100% at 200–350 °C. In the presence of SO 2 and H 2 O, the NO x conversion was maintained at 87%. The spherical structure consisting of nanospikes provides the Mn-SNS catalysts with a large specific surface area, more (Mn 4+ +Mn 3+ ), abundant acid sites, and stronger reducibility, thus exhibiting excellent performance through the "fast-SCR" pathway. It also inhibits oxide crystallization and provides more sites for the adsorption activation of NO x and NH 3 . The nanowire structures can provide a large specific surface area and a high concentration of Mn 3+ and Mn 4+ for MnO x catalyst. Characterization analyses revealed that the specific surface area, the ratio of (Mn 4+ +Mn 3+ )/Mn, and the number of Lewis acid sites (L-NH 3 ) are the most important factors affecting the catalytic activity. This present empirical analysis provides new ideas for designing high-performance catalysts with a large specific surface area.
研究领域:
环境科学
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催化科学
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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
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2017
·Vol. 19
·期 7
·5333-5342
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IF 4.123
Shu-xian Wang,Rui-tang Guo,Wei-guo Pan,Ming-yuan Li,Peng Sun,Shu-ming Liu,Shuai-wei Liu,Xiao Sun,Jian Liu
It was well recognized that Pb had a poisoning effect on a SCR catalyst. In this study, the deactivation mechanism of Pb on the Ce/TiO2 catalyst was investigated based on the characterization results of TPD and in situ DRIFT studies. It was found that the addition of Pb on the Ce/TiO2 catalyst not only inhibited the adsorption and activation of NH3 species, but also led to the decrease of the activity of adsorbed NH3 species in the SCR reaction. The adsorption of NOx species and the oxidation of NO by O2 over the Ce/TiO2 catalyst were also suppressed by the addition of Pb, while the reactivity of adsorbed NO2 species did not decrease. Moreover, the results revealed that the NH3-SCR reaction over the Ce/TiO2 catalyst followed both the E–R and L–H mechanisms, while the NH3-SCR reaction over Ce/TiO2-Pb was mainly controlled by the L–H mechanism. The contributions of the L–H mechanism to the SCR reactions over Ce/TiO2 and Ce/TiO2-Pb decreased with increasing reaction temperature. The deactivation of Ce/TiO2-Pb was mainly attributed to the suppressed NH3 adsorption and activation, accompanied by the inhibited NO oxidation and the decrease of Brønsted acid sites.
研究领域:
环境催化
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大气污染控制
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材料化学
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表面科学
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物理化学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2019
·
IF 4.63
Li Cao,Xiaodong Wu,Ze Chen,Yue Ma,Ziran Ma,Rui Ran,Zhichun Si,Duan Weng,Baodong Wang
CeO 2 /WO 3 -TiO 2 (CeWTi) and Nb 2 O 5 -CeO 2 /WO 3 -TiO 2 (NbCeWTi) catalysts were prepared by a sol-gel precipitation method. Both the catalysts exhibit high selective catalytic reduction of NO x with NH 3 (NH 3 -SCR) activities at 270–500 °C. The sulfur tolerances of the catalysts were evaluated at 270 °C by adding H 2 O and SO 2 in the feeding gas and NbCeWTi exhibited a significantly improved resistance. The thermogravimetric (TG) and mass spectrographic (MS) results indicated that much less sulfates formed on NbCeWTi and existed mainly in the form of ammonium hydrogen sulfate species which protected Ce x+ active sites effectively from attacking of SO 2 . According to the results of temperature-programmed desorption of ammonia (NH 3 -TPD), H 2 temperature-programmed reduction (H 2 -TPR) and SO 2 oxidation , loading niobia on CeWTi inhibited the SO 2 oxidative adsorption and SO 3 production which basically reduced sulfur poisoning of the catalyst. Additionally, the niobia modification ensured the formation of nitrates from the competitive adsorption of SO 2 and hereby facilitated the nitrate SCR route based on the in situ diffuse reflectance infrared Fourier transform spectra (DRIFTS).
研究领域:
催化
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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
SENSORS
·
2024
·Vol. 24
·期 6
·1824
·
IF 3.4
Yuan Qu,Haotian Zheng,Yuhua Lei,Ziwen Ding,Siqi Li,Song Liu,Wei Ji
Morphology and structure play a crucial role in influencing the performance of gas sensors. Hollow structures, in particular, not only increase the specific surface area of the material but also enhance the collision frequency of gases within the shell, and have been studied in depth in the field of gas sensing. Taking SnO2as an illustrative example, a dual-shell structure SnO2(D-SnO2) was prepared. D-SnO2@Polyaniline (PANI) (DSPx, x represents D-SnO2molar content) composites were synthesized via the in situ oxidative polymerization method, and simultaneously deposited onto a polyethylene terephthalate (PET) substrate to fabricate an electrode-free, flexible sensor. The impact of the SnO2content on the sensing performance of the DSPx-based sensor for NH3detection at room temperature was discussed. The results showed that the response of a 20 mol% D-SnO2@PANI (DSP20) sensor to 100 ppm NH3at room temperature is 37.92, which is 5.1 times higher than that of a pristine PANI sensor. Moreover, the DSP20 sensor demonstrated a rapid response and recovery rate at the concentration of 10 ppm NH3, with response and recovery times of 182 s and 86 s.
研究领域:
材料科学
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纳米技术
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气体传感
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化学传感器
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2023
·
IF 22.1
Ning Luo,Fengyu Gao,Hengheng Liu,Tingkai Xiong,Jiajun Wen,Erhong Duan,Chengzhi Wang,Shunzheng Zhao,Honghong Yi,Xiaolong Tang
Developing effective and stable catalysts for low-temperature selective catalytic reduction (SCR) of NO x remains challenging. Herein, we constructed a hierarchical structure by loading CoMn 2 O 4 onto Ti-doped CeO 2 , that CoMn 2 O 4 /CeTiO x catalyst has shown superior deNO x activity (>95% at 100–225 °C), prominent reaction activation energy (28.8 ± 0.9 kJ mol −1 ) and outstanding stability (>75% at 100–200 °C within H 2 O and SO 2 ). The “low-temperature active sites” and “dual anti-poisoning sites” contribute to excellent activity and stability. Firstly, the hierarchical structure boosts generation of active metal-support interface, which is conducive to oxygen migration (including adsorbed oxygen (O ads ), lattice oxygen (O lat ) and oxygen vacancy (O v )) and metal charge transfer (Mn 2+/3+ +Ce 4+ ↔Mn 3+/4+ +Ce 3+ , Ti 4+ +Ce 3+ ↔Ce 4+ +Ti 3+ ). This is the key to breaking through the limits of catalytic activity stability. Secondly, enhanced surface acidity favors NH 3 adsorption and activation, which accelerates -NH 2 /-NH concatenate with NO x through Eley-Rideal mechanism to generate N 2 and H 2 O. Thirdly, the dual strong SO 2 affinity sites by Ti-induced CeO 2 crystal reconstruction retard the active center affected by the sulfate species, which contributes to striking stability. This work highlights the importance of design of isolated active sites to improve SO 2 and H 2 O endurance.
研究领域:
催化
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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
Journal of Environmental Chemical Engineering
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2022
·
IF 7.968
Beilei Li,Xiaoxiang Wang,Yaqing Wang,Weijia Wang,Shuguang Zhou,Shihan Zhang,Wei Li,Sujing Li
Elimination of NO x from the non-electric industrial boilers has become priority under the effective implementation of ultra-low emissions. A series of Ce-promoted FeVO 4 catalysts with improved acidity and reducibility have been synthesized in this work. Thereinto, 10Ce/FeVO 4 exhibited an optimum low-temperature performance with 90% of NO x conversion and 95% of N 2 selectivity at 200–300 °C which was kept nearly unchanged with different concentrations of SO 2 ranging from 50 ppm to 200 ppm, showing a superior sulfur tolerance. An array of well-designed experiments has demonstrated that Ce mainly existed as CeVO 4 under a low doping content (1 wt%) on FeVO 4 , which could efficiently increase the amount of acid sites. With more cerium (5–12 wt%) loading on FeVO 4 , the appearance of CeO 2 further resulted in a strong interaction between cerium species and ion species, thus significantly improving the low-temperature catalytic activity . Therefore, the optimum coexistence of CeVO 4 and CeO 2 over 10Ce/FeVO 4 modulated its Brønsted acid and enhanced its redox circulation of Fe 3+ species. Moreover, the NH 3 -SCR reaction pathways of 10Ce/FeVO 4 were broadened from only Eley-Rideal to both Eley-Rideal and Langmiur-Hinshelwood mechanisms after Ce loading on FeVO 4 catalyst. With the presence of SO 2 , the S O/S-O deriving from the generated Ce 2 (SO 4 ) 3 and NH 4 HSO 4 increased the Brønsted acid sites, inducing a satisfying SO 2 tolerance of 10Ce/FeVO 4 catalyst, although the Langmiur-Hinshelwood pathway of 10Ce/FeVO 4 was immediately cut off due to the competitive adsorption of gaseous SO 2 and NO x . This work exemplifies a promising strategy for developing an ideal low-temperature NH 3 -SCR catalyst with good SO 2 resistance.
研究领域:
催化
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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
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Peng Wang,Chengli Tang,Libing Zhang,Yebo Lu,Fengli Huang
Ammonia (NH 3 ) gas is regarded as a biomarker for clinical diagnosis of various diseases and a potential indicator for the spoilage of protein-rich foods. The acuate detection of the ammonia gas concentration depend on reliable gas sensor. In this paper, flexible room temperature ammonia gas sensor based on hierarchical Au/PANI/WS 2 ternary composite was successfully prepared by in-situ polymerization, reduction and drop-coating process. The Au/PANI/WS 2 -based ammonia sensor was tested for its room temperature sensing property including response value, response/recovery time, selectivity, and long-term stability. The effects of flexible state, humidity and operating temperature on the sensor response were also investigated. The 0D/1D/2D Au/PANI/WS 2 -based sensor showed significantly enhanced ammonia sensing property both in response and response/recovery time as compared to that of pristine WS 2 . Gas sensing mechanism of the prepared sensor was investigated by complex impedance spectroscopy and in-situ fourier transform infrared spectroscopy analysis. Besides, the sensor was proved for its practical usability in seafood spoilage detection and warning. The construction of multidimensional materials into hierarchical structure may provide an instructive way for the sensibilization of layered two-dimensional nanomaterial of WS 2.
研究领域:
材料科学
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纳米技术
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传感器技术
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食品科学
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分析化学
✓ 已验证
产品关联
DOI
高影响因子
Chemistry-An Asian Journal
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2020
·Vol. 15
·期 8
·1272-1276
·
IF 4.056
Yueming Cao,Peipei Li,Tengteng Wu,Meiling Liu,Youyu Zhang
Graphical HKUST-1 (Cu−BTC, BTC=benzene-1,3,5 tricarboxylate) was selected as an electrocatalyst for the reaction of conversion N 2 to NH 3 under ambient conditions. At −0.75 V vs. reversible hydrogen electrode, it achieves excellent performance with high NH 3 yield (46.63 μg h −1 mg −1 cat. or 4.66 μg h −1 cm −2 ) and Faraday efficiency (2.45%). Electrolytic ammonia synthesis from nitrogen at ambient conditions is appearing as a promising alternative to the Haber-Bosch process which is consuming high energy and emitting CO 2 . Here, a typical MOF material, HKUST-1 (Cu−BTC, BTC=benzene-1,3,5-tricarboxylate), was selected as an electrocatalyst for the reaction of converting N 2 to NH 3 under ambient conditions. At −0.75 V vs. reversible hydrogen electrode, it achieves excellent catalytic performance in the electrochemical synthesis of ammonia with high NH 3 yield (46.63 μg h −1 mg −1 cat. or 4.66 μg h −1 cm −2 ) and good Faraday efficiency (2.45%). It is indicated that the good performance of the HKUST-1 catalyst may originate from the formation of Cu(I). In addition, the catalyst also has good selectivity for N 2 to NH 3 .
研究领域:
材料科学
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电化学
·
催化反应
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Dongshun Deng,Xiaoxia Deng,Ke Li,Hao Fang
Development of high-efficient absorbents for ammonia (NH 3 ) to improve the quality of atmosphere and ecological environment has gained interest among scholars. Ionic liquids (ILs) with unique properties have been reported as potential solvents for NH 3 uptake to avoid many problems troubling the traditional NH 3 capture technology. In this study, six protic ethanolamine-based ILs (PILs) were synthesized for efficient and reversible NH 3 uptake, with the initial idea of constructing multiple binding sites to enhance the absorption ability for NH 3 . The physical properties and NH 3 absorption performance in these PILs were investigated and analysized on the basis of molecular structures. The results demonstrated that the preferred [EtAN][SCN] had suitable viscosity of 78.18 mPa.s and molality capacity up to 0.296 and 0.0802 g NH 3 /g PILs at 100.0 and 4.5 kPa NH 3 pressure, respectively. Such absorption ability was higher than all the reported absorbents related with ILs. 1 H NMR spectroscopy illustrated that the outstanding absorption ability was originated from multiple hydrogen-bonding interactions between acidic proton, hydroxyl group and thiocyanate with NH 3 . The absorption enthalpy of −35.5 kJ/mol was further calculated according to the absorption capacity at low NH 3 pressure under corresponding temperatures. In short, present PILs exhibited attractive absorption ability, excellent recyclability, low absorption enthalpy, and competitive selectivity of NH 3 /CO 2 . Present work can provide instructive idea for designing PILs in NH 3 recovery and separation application.
研究领域:
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
Molecular Catalysis
·
2025
·
IF 4.9
Qiuju Qin,Chaolian Zhu,Donghai Mo,Zhengjun Chen,Lihui Dong,Bin Li,Liya Zhou
MnO x exhibits excellent low temperature activity for degradation NO x , but its poor SO 2 tolerance restrains its application. Herein, an in situ construction method for MnO x loading on Mn-doped ZrO 2 carrier with carbon (MnO x /Mn-ZrO 2 -C) derived from Mn(NO 3 ) 2 /UIO-66 by in situ doped pyrolysis–oxidation, in which Mn replaces Zr to modify the electronic structure of the ZrO 2 . The MnO x /Mn-ZrO 2 -C with abundant surface oxygen and acid sites showed excellent activity and better SO 2 resistance. A series of characterization results indicated that Mn doping modulates the electron structure of carrier ZrO 2 and enhances the interactions among MnO x , carbon, and Mn-ZrO 2 , resulting in increasing the electron cloud density around Mn and Zr, and consequently, the Mn and Zr on the MnO x /Mn-ZrO 2 -C exhibit poorer sulfiphilic. These findings emphasize the benefits of utilizing a multipronged effect to fabricate highly active and sulfur-resistant NH 3 -SCR 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
FUEL
·
2024
·
IF 6.7
Qitong Xue,Jiaying Xing,Jianjun Chen,Jinxing Mi,Jianqiang Shi,Yao Wang,Junhua Li,Zhiming Liu
V 2 O 5 /TiO 2 has been wide used in the selective catalytic reduction of NO x by NH 3 (NH 3 -SCR). However, the poisoning mechanism of thallium (Tl) on the catalytic performance of commercial V 2 O 5 /TiO 2 catalyst has remained unclear. Herein, we have systematically investigated the poisoning effect of Tl based on the different characterizations and DFT calculations. It was found that the strong interaction between V and Tl exists, resulting in the transformation of V from monomeric VO x to polymeric and crystalline VO x , the formation of V-O-Tl species, a decrease in the active V 5+ sites, and the inhibition of the adsorption and activation of NH 3 on both Brønsted and Lewis acid sites. Mechanistic studies further confirmed that inactive nitrate intermediate species gradually accumulated over V 2 O 5 /TiO 2 catalyst surface due to the presence of Tl. A combination of factors ultimately led to the deactivation of the V 2 O 5 /TiO 2 catalyst. This study unveils the poisoning mechanism of Tl on V-based catalysts and shed light on the design of Tl-tolerant NH 3 -SCR catalysts.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Jiangtao Meng,Jing Wang,Fengling Yang,Fangqin Cheng
This study proposed a novel strategy to control nitrogen oxides (NOx) precursors by directing nitrogen to adhere to the fuel-N→NH 3 →N 2 pathway. The research aimed to illuminate the regulatory effects of CaO, Fe 2 O 3 , and their mixtures on NO and N 2 O precursors (NH 3 , HCN, and HNCO) during sludge pyrolysis, further sought to establish scientific correlations with varying temperatures and differentiate their impact. The findings indicated that unlike NH 3 , HNCO is generated from the cleavage of amides, sharing its origin with HCN. Notably, the sensitivities of three conditioners to different functional groups result in distinct impacts on precursor emissions. CaO interacted with –OH and N-H functional groups, releasing NH 3 . Fe 2 O 3 , being more responsive to C-H and C-C groups, contributed to HNCO emission. At 750 °C, a CaO-Fe 2 O 3 mixture created Ca x Fe y O z , which selectively reacted with N-H and C≡N, facilitating the conversion of HNCO and HCN to NH 3 . While temperature is a crucial factor in the performance of CaO, its impact on Fe 2 O 3 is primarily confined to transformation of heterocyclic and nitrile . Below 350 °C, Fe 2 O 3 favored the evolution of nitrogen into heterocyclic compounds within tar. Conversely, above 490 °C, it inhibited the formation of nitrile in char, promoting the dehydrogenation of tar into unsaturated aromatic structures. The CaO-Fe 2 O 3 mixtures exhibited a superposition of individual effects from CaO and Fe 2 O 3 , with Ca x Fe y O z stimulating N 2 emission. Importantly, among three conditioners, Fe 2 O 3 showed the most significant abatement effect on NOx precursors, primarily through nitrogen fixation in char, nitrogen enrichment in tar, and precursor oxidation. This research contributes innovative perspectives on nitrogen regulation in nitrogen-rich fuels, the utilization of NH 3 , and effective NO and N 2 O control.
研究领域:
环境科学
·
能源工程
✓ 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）