INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2018
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IF 3.141
Dongyue Zhao,Zhongnan Gao,Hui Xian,Lingli Xing,Yuexi Yang,Ye Tian,Tong Ding,Zheng Jiang,Jing Zhang,Lirong Zheng,Xingang Li
Herein, we report the function of Pd species in the Pd-added La0.7Sr0.3CoO3 perovskite for removal of NOx (NO+NO2) in the lean-burn NOx traps (LNT) process. The addition of Pd significantly improves the De-NOx activity of the perovskite-based catalysts. The Pd-supported catalyst has an excellent NOx removal efficiency of 90.4%, which is higher than the Pd-doped catalyst (74.4%) and pure La0.7Sr0.3CoO3 (51.6%). Our results show that the addition of Pd species enhances both the NOx desorption behaviors to regenerate the NOx storage sites and NOx reduction ability of the catalysts in the fuel-rich period, which induces the improved NOx trapping performance in the followed lean-burn period. These achievements result in the enhanced De-NOx activity of the Pd-added catalyst in the alternative NOx storage and reduction operations. Compared with the Pd-doped catalyst, the Pd-supported catalyst possesses the higher utilization efficiency of the Pd, thus exhibiting a higher catalytic activity.
研究领域:
化学
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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 RARE EARTHS
·
2023
·
IF 4.9
Songil Sin,Jiawei Ji,Lijun Cheng,Zhiwen Gu,Chong Tan,Kwangchol Ri,Changjin Tang
CeO 2 -based catalysts are widely investigated for selective catalytic reduction (SCR) of NO with NH 3 . Interaction of NO/O 2 with CeO 2 generally produces two surface species, i.e., nitrates and nitrites. However, the explicit quantification of these two species is still unresolved. Herein, we reported that spectrophotometry characterization was effective in determining surface adsorbed NO x species on CeO 2 by measuring the corresponding ions (NO 2 – and NO 3 – ) dissolved in aqueous solution. Experimental results show that both nitrate (–NO 3 ) and nitrite (–NO 2 ) species can be quantitatively evaluated and the accuracy is verified by calibrating with NO x -TPD result. Exclusive transfer of adsorbed NO x from catalyst surface to aqueous solution is confirmed and the dissolution process can be accelerated by ultrasonic treatment. Moreover, useful information related to evolution of surface NO x species under various conditions (O 2 treatment, different adsorption temperature and duration) and over different catalysts (Fe 2 O 3 , MnO 2 and MnO x –CeO 2 ) are provided. The result of present study demonstrates the potential of spectrophotometry for quantitative discrimination of surface NO x species on CeO 2 and other oxide-based materials, which is conducive to mechanism analysis of SCR 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
INORGANIC CHEMISTRY COMMUNICATIONS
·
2023
·
IF 3.8
Xudong Liu,Fengyuan Liu,Junqi Li,Yuanpei Lan,Jian Yang,Arun Murali,Chaoyi Chen,Wei Zhang
To accurately evaluate the phase effects of MnO x in Mn-Ce catalysts towards to low temperature NO x removal performance with NH 3 , MnCO 3 @CeCO 3 OH was synthesized firstly and decomposed to MnO 2 @CeO 2 , Mn 2 O 3 @CeO 2 and Mn 3 O 4 @CeO 2 with similar size and morphology, this will avoid the influence of size and morphology on the experimental results. Experimental results show that the MnO 2 @CeO 2 exhibiting the best NO conversion ratio, which achieved nearly 96.5 % at a low temperature of 150 °C, and the catalytic performance order of MnO x @CeO 2 is determined as: MnO 2 @CeO 2 > Mn 2 O 3 @CeO 2 > Mn 3 O 4 @CeO 2 below 200 °C, and MnO 2 @CeO 2 > Mn 2 O 3 @CeO 2 ≈Mn 3 O 4 @CeO 2 at range of 200 –400 °C. But the N 2 selectivity of Mn 2 O 3 @CeO 2 reaches 96 % at 100 °C which was higher than that of MnO 2 @CeO 2 and Mn 3 O 4 @CeO 2 . Characterizations including BET, XRD, SEM, H 2 -TPR, NH 3 -TPD and FTIR show that MnO 2 @CeO 2 has maximum specific surface area, a stronger redox ability, and more surface acid sites.
研究领域:
催化材料
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Qinyu Zhou,Chong Tan,Tianfa Tang,Yu Wang,Siyuan Li,Meilin Tao,Hongliang Zhang,Liu Yang,Changjin Tang
The occurrence of NH 3 over-oxidation represents one intractable challenge for the effective application of NH 3 -SCR technology. Herein, a rational NO x activation strategy was innovatively proposed to counteract NH 3 over-oxidation during high temperature NH 3 -SCR. As a proof of concept, the hybrid catalyst of CeO 2 -ZSM-5 was explored. It was shown that the activity of CeO 2 in NH 3 -SCR was profoundly improved via physically mixing with ZSM-5, achieving more than 85 % NO at 500 °C, in sharp contrast to the negative NO conversion present for pristine CeO 2 . Comprehensive characterizations from NH 3 -TPD, NO-TPD and in situ DRIFTS verified the negligible modification of NH 3 oxidation but significant alteration of surface NO x . Due to the facile NO x activation, the reaction of NH 3 + NO x overwhelms that of NH 3 + O 2 , leading to the obtainment of excellent high temperature NH 3 -SCR performance. The novel strategy reported here is expected to provide valuable guidance for designing NH 3 -SCR catalysts with superior high temperature performance.
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Benyong Yang,Wentao Mu,Benedict Tsz Woon Lo,Sijie Liu,Zhihang Chen,Liam John France,Xuehui Li
NOx and CO formation is, at present, a consequence arising from fuel production, but their emission need not be. In this study, a series of novel Ir-containing TiO2-nanobelt catalysts were designed and prepared for the simultaneous removal of NOx and CO. Activity data demonstrates that the TiO2(B) support promotes NO reduction compared to anatase. Furthermore, reaction efficiency (RE), a measure of NOx consumption vis-à-vis that of CO, reveals that catalysts containing anatase promote CO oxidation more so than their TiO2(B) counterparts. Increasing Ir concentration over the latter promotes low-temperature catalytic performance, an effect believed to be linked to the formation of Ir0–IrO2 composites. In situ DRIFTS experiments reveal the relevance of nitrite/nitrate formation and consumption at 250 °C, a mechanism insinuated by the RE value. However, at 300 °C, both TOF and RE increase, signifying the participation of a faster and more-selective reaction, which appears consistent with the isocyanate-mediated pathway.
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
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Yi Li,Yanping Li,Pengfei Wang,Wenping Hu,Suge Zhang,Qiang Shi,Sihui Zhan
A series of MnFeO x nanorods with different Fe/Mn molar ratios were successfully synthesized by the hydrothermal method for low temperature selective catalytic reduction (SCR) of NO x with NH 3 . These MnFeO x catalysts have been systematically characterized by SEM, TEM, XRD and XPS. Furthermore, the MnFe (0.1) O x showed the highest catalytic performance with nearly 100% of NO x removal efficiency from 200 to 350 °C. On the basis of the TPR, BET and in situ DRIFT results, it can be found that the addition of Fe species induced a possible redox reaction process and increased the surface chemisorbed oxygen concentration and acid sites, which should be responsible for the enhanced SCR activity of MnFe (0.1) O x . Meanwhile, several important process parameters affecting NO x removal efficiency in NH 3 -SCR were carried out, such as time, H 2 O and SO 2 .
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
RESEARCH ON CHEMICAL INTERMEDIATES
·
2022
·Vol. 48
·期 7
·3007-3018
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IF 3.134
Liu Fengyuan,Li Junqi,Chen Chaoyi,Ning Deyang,Yang Jian,Chu Zhiyao,Mao Xisong,Lan Yuanpei
A novel tactic was employed to evaluate the low-temperature NH 3 -SCR (selective catalytic reduction) NO x removal property of manganese oxides (MnO x ) in various valence states, avoiding the influences of size, morphology and synthetic method on catalytic activity. Firstly, similar sized hollow-spherical MnO 2 , Mn 2 O 3 , Mn 3 O 4 and MnO were obtained by decomposing MnCO 3 at 440 and 500 °C in Air, 430 °C in H 2 and Ar, respectively. The orders of MnO x catalytic activity varied at different reaction temperature range, while MnO 2 showed the best NO conversion. Surface acidity has significant influences on the SCR activity, Mn 3 O 4 exhibits a better catalytic property than Mn 2 O 3 below 300 °C, and conversely, Mn 2 O 3 has a better high-temperature NO conversation than Mn 3 O 4 due to a stronger NH 3 adsorption ability above 300 °C. MnO will be oxidized in the studied atmosphere with 5% O 2 to Mn 3 O 4 , Mn 5 O 8 and finally to Mn 2 O 3 successively, and the mixed phases of MnO/Mn 3 O 4 or Mn 3 O 4 /Mn 5 O 8 exhibit a better catalytic activity than Mn 2 O 3 at 200–300 °C.
研究领域:
环境科学
·
催化材料
✓ 已验证
产品关联
DOI
高影响因子
Journal of Chemistry
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2017
·
IF 1.3
Zhitao Han,Bojun Liu,Shaolong Yang,Xinxiang Pan,Zhijun Yan
The experiments were performed in a lab-scale countercurrent spraying reactor to study the NOx removal from simulated gas stream by cyclic scrubbing using NaClO solution. The effects of NaClO concentration, initial solution pH, coexisting gases (5% CO2 and 13% O2), NOx concentration, SO2 concentration, and absorbent temperature on NOx removal efficiency were investigated in regard to marine exhaust gas. When NaClO concentration was higher than 0.05 M and initial solution pH was below 8, NOx removal efficiency was relatively stable and it was higher than 60%. The coexisting CO2 (5%) had little effect on NOx removal efficiency, but the outlet CO2 concentration decreased slowly with the initial pH increasing from 6 to 8. A complete removal of SO2 and NO could be achieved simultaneously at 293 K, initial pH of 6, and NaClO concentration of 0.05 M, while the outlet NO2 concentration increased slightly with the increase of inlet SO2 concentration. NOx removal efficiency increased slightly with the increase of absorbent temperature. The relevant reaction mechanisms for the oxidation and absorption of NO with NaClO were also discussed. The results indicated that it was of great potential for NOx removal from marine exhaust gas by wet scrubbing using NaClO solution.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2019
·
IF 4.507
Haotian Li,Feng Liu,Shuhui Wang,Fengjia Wang,Xin Qian,Caiduan Zhang,Yongliang Ma,Lidong Wang
Based on advanced oxidation technology, a new method for the simultaneous removal of SO 2 and NO x from industrial flue gas using Na 2 S 2 O 8 /MgO was proposed. The method does not require the body structure of the wet desulfurization device is changed but adds Na 2 S 2 O 8 to the original equipment to realize simultaneous desulfurization and denitrification. After determining Cl − was additive, the effects of various reaction factors on the simultaneous removal of SO 2 and NO x were investigated, including the Cl − concentration, the initial concentration of the oxidant, the initial pH value of the solution, and the reaction temperature. According to the characterization of removal products and the types of free radicals involved in the reaction by XRD , XPS , and EPR , the reaction mechanism was elucidated. The experimental results indicated that the removal products were mainly sulfates and nitrates. The free radicals involved in the reaction were SO 4 ·− , ·OH, and Cl·, and the key free radical was Cl·.
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
JOURNAL OF ALLOYS AND COMPOUNDS
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2022
·
IF 6.371
Baowei Cao,Dachuan He,Fei Rao,Qadeer Ul Hassan,Xiaolong Cai,Lingna Liu,Fan Xue,Gangqiang Zhu
BiOI-loaded flower-like CeO 2 (BiOI/CeO 2 ) p-n heterojunction was synthesized via a simple two-step chemical route. The phase structure and chemical states of the heterojunction were analyzed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The transmission electron microscopic (TEM) and the scanning electron microscope (SEM) reveal the close contact between BiOI and CeO 2 . The formation of the p-n heterojunction is verified by the Mott-Schottky curves. The p-type BiOI with a narrow band-gap when loaded on CeO 2 can not only improve the separation of photogenerated electron-hole pairs but also facilitate the absorption of visible light. The photo-oxidative removal efficiency of 9%BiOI/CeO 2 among other heterojunctions for NO reaches 45.49% and remains highly stable with an efficiency of 40.40% after the five cycles. Trapping experiments and ESR measurements were conducted to explore the contribution of charge carriers and the reactive oxygen species during the photocatalytic NO removal. This work highlights that constructing such p-n heterojunction by loading BiOI on CeO 2 microstructures can significantly enhance photocatalytic NO removal.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Qingsong Zhang,Meng Sun,Weidi Qin,Yang Xiao,Chunlei Zhang,Hui Yu,Liangshu Xia
Multilayer ZnO nanoflowers constructed by many nanograins with highly exposed {0001} facet have been prepared. The grain size and exposed {0001} facet is adjusted by hydrothermal condition and citrate-assisted steric hindrance, respectively. Subsequently, the gas sensing performances of the as-prepared ZnO sensors with various hydrothermal temperatures and times were investigated. The detailedly sensing experiments demonstrated that when the hydrothermal temperature and time are 120 °C and 9h, respectively, the obtained ZnO nanoflower sensor (ZnO-120-9) possesses optimal response of 80.3 towards 100 ppm NO x gas concentration at 180 °C. Meanwhile, ZnO-120-9 exhibits excellent selectivity, rapid response and recovery time, and also shows an obvious response signal at 0.5 ppm NO x exposure, which manifests that the lower concentration detection is also attainable. The superior performance of ZnO-120-9 towards NO x is due to the highly exposed {0001} facet and the size comparable to Debye length. As a result, such structure is conducive to the adsorption of more oxygen species and significant reduction of resistance, and they improve the sensitivity of a sensor.
研究领域:
材料科学
·
传感器技术
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2020
·Vol. 7
·期 12
·125502
·
IF 1.929
Lei Zhao,Kun Li,Ruian Wu,Hua Zhang,Jiang Jin
The catalytic filter was fabricated by supporting selective catalytic reduction (SCR) catalyst on the low-density ceramic (LDC) for the removal of dust and nitrogen oxides (NOx) in the flue gases at relative low temperature. MnOx–ZrO2/TiO2 catalyst was selected as SCR catalyst. The NOx and dust removal efficiency, filter resistance, regeneration performance and anti-sulfur performance were investigated. The result showed that the NOx removal efficiency at 180°C reached 98.4% (1 m/min filtration velocity) for 6 wt% MnOx–ZrO2/TiO2 catalytic filter with Mn/Zr molar ratio of 2. Furthermore, MnOx–ZrO2/TiO2 catalytic filter performed good anti-sulfur performance. In the presence of 10 vol% water vapor and 100 ppm SO2 at 180 °C, the NOx removal efficiency for MnOx–ZrO2/TiO2 catalytic filter could retain up to 83.2% and it could recover to 91.8% when the water vapor and SO2 were cut off. MnOx–ZrO2/TiO2 catalytic filter showed the high dust removal efficiency of 99.99% and the low filter resistance of less than 200 Pa. The filter resistance of MnOx–ZrO2 /TiO2 catalytic filter could maintain 235.7 Pa after 200 times pulse blowback. The result illustrated that MnOx–ZrO2/TiO2 catalytic filter showed good regeneration performance.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）