Journal of Physical Chemistry C
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2021
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IF 4.126
Yanye Zhu,Fangyuan Zhou,Xiaoqiang Wang,Yue Liu,Zhongbiao Wu
The NH3–SCR process could provide cobenefits for VOCs abatement from industrial sources. Ceria-based catalysts have received considerable attention for NOx removal at low-medium temperatures. In this study, the reaction behaviors of the simultaneous control of NOx and methanol over the Sb0.5CeZr2Ox catalyst were investigated. It was found that the presence of methanol reduced NOx conversion at low temperatures, while the methanol mineralization rate was promoted in the SCR reaction environment. This effect weakened as the temperature increased, and both NOx and methanol could be effectively removed (with efficiencies more than 90%) within 250–350 °C at a CH3OH/NO ratio of no more than 1:1. NO adsorption and oxidation were greatly suppressed by methanol, thereby inhibiting the SCR reaction via the Langmuir–Hinshelwood (L-H) mechanism. Meanwhile, the formation of formamide via NH3 and intermediates of methanol oxidation was also responsible for the deactivation effect on the SCR reaction at low temperatures. The presence of NO was found to be the main reason for enhanced methanol deep oxidation as NO can promote the rehealing process of active oxygen species.
研究领域:
环境科学
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催化化学
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DOI
高影响因子
ChemistrySelect
·
2024
·Vol. 9
·期 28
·e202401039
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IF 1.9
Xueqi Wang,Kai Li,Fei Wang,Lei Shi,Shuangyou Bao,Jiacheng Bao,Xin Sun
Graphical In this study, we prepared the thermally modified copper slag catalyst CS-CaO-900 and applied it to a pilot-scale Fenton-like denitrification system. In single-factor experiments, the effects of six factors, namely inlet NO concentration, H 2 O 2 concentration, catalyst dosage, reaction temperature, L/G ratio, and pH value, on desulfurization and denitrification were investigated. Through analysis of the experimental results, the three factors that had the greatest impact on the maximum denitrification efficiency, namely pH value, H 2 O 2 concentration, and reaction temperature, were selected. The response surface methodology was employed to investigate the significance of the three factors and optimize the parameters, and it was finally determined that the initial pH of the slurry had the greatest impact on the maximum denitrification efficiency, followed by the H 2 O 2 concentration. At the same time, the combination of initial slurry pH and reaction temperature, initial slurry pH and H 2 O 2 concentration also had a large impact on the maximum denitrification efficiency, and the combination of reaction temperature and H 2 O 2 concentration had a non-significant impact on the denitrification efficiency. And through the model optimization to get the best parameters, denitrification experiments under this parameter to achieve the maximum denitrification efficiency of 91.5 %, for further industrial application to provide reference and guidance. In this study, Response Surface Methodology (RSM) was employed to optimize the experimental factors influencing the simultaneous removal of NOx and SO 2 in a spray tower wet scrubbing experiment. Thermally modified copper slag (CS-CaO-900) was prepared by heat treating the original copper slag. The performance of CS-CaO-900 in the synchronized removal of NOx and SO 2 was then evaluated in an expanded experimental setup. Based on single-factor experimental results, the Box-Behnken design of RSM was used to optimize the reaction parameters in a two-stage sequential reactor (bubbling reactor + spray tower). NOx removal efficiency was modeled as a function of reaction temperature, pH, and H 2 O 2 concentration. Regression curves provided a visual representation of the interaction effects among these parameters on NOx removal efficiency in the thermally modified copper slag/H 2 O 2 composite slurry. This study elucidates the characteristics of each parameter under wet scrubbing conditions and provides essential data for industrial applications.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
Journal of Energy Chemistry
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2020
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IF 7.216
Huimin Liu,Yidan Zhang,Jingshan Luo
Ammonia synthesis by electrocatalytic nitrogen reduction reaction (NRR) is considered as a promising alternative to the Haber−Bosch process. However, due to the extremely low ammonia yield and easily accessible extraneous contamination in the laboratory, NRR study always suffers from fluctuation and variability. Finding and eliminating all kinds of possible extraneous contamination is crucial to evaluate the performance of electrocatalytic ammonia synthesis accurately. In this work, we systematically explored two factors that affect NRR results but are easy to be ignored: the selection of membrane for NRR and the unconscious N-source in NRR catalysts. After series of experiments, we proposed a low-cost and almost pollution-free Celgard 3501 membrane as the separator for NRR to avoid the adsorption and release of ammonia by the membrane. In addition, we proposed a pre-reduction strategy to remove residual or adsorbed NO x contaminants in catalysts. These two solutions will help the community to evaluate the NRR activity more accurately.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
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2024
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IF 6.5
Ruoyuan Li,Aixia Li,Junhua Li,Yao Wang,Zhiming Liu
Selective catalytic reduction of NO x by CO (CO-SCR) in the presence of O 2 is challenging because in this process CO is prone to being oxidized by O 2 , thus inhibiting NO x reduction by CO. Furthermore, SO 2 typically leads to the deactivation of the CO-SCR catalyst. Herein, a significant promoting effect of SO 2 on Ir/SiO 2 catalyst for the CO-SCR of NO x in the presence of O 2 is reported. In-situ X-ray Absorption Fine Structure (XAFS) and X-ray photoelectron spectroscopy (XPS) analysis showed that SO 2 does not affect the chemical nature of Ir 0 under reaction conditions. However, SO 2 can be oxidized to sulfate and deposit on the catalyst surface. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis demonstrated that the presence of SO 2 can inhibit the CO + O 2 reaction, thus leaving more CO available to reduce NO x over the active Ir 0 sites. As a result, the reduction of NO x is remarkably promoted even in the presence of O 2 and SO 2 .
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
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Yuting Hu,Minghu Zhao,Bo Du,Ting Cheng,Zhaozhong Jiang,Kai Qin,Chengzhu Zhu
A series of M-MnCeO X catalysts using MOF (Metal-organic Framework) were prepared to apply for NH 3 -SCR (Selective Catalytic Reduction) of NO X . The effects of Mn/Ce molar ratio, calcination temperature and its activity including catalytic activity, H 2 O/SO 2 resistance and stability were systematically investigated. The results showed that under the Mn/Ce molar ratio of 1 and calcination temperature of 400 ℃, the catalyst exhibited excellent catalytic activity, H 2 O/SO 2 resistance, and stability. When the concentration of NO was 500 ppm, the gas spatiotemporal velocity (GHSV) was 36,000 h −1 , and the reaction temperature was 100 ℃, the NO conversion efficiency of M-MnCeO X exceeded 90.0 %. Added 200 ppm SO 2 and 3 vol% H 2 O simultaneously, the NO conversion efficiency was close to 80.0 %. By analyzing the physicochemical properties of the catalyst, M-MnCeO X had a large specific surface area, numerous acidic sites, and excellent redox properties. According to density functional theory (DFT), the NH 3 /NO adsorption energy of M-MnCeO X were −2.35 and −2.40 eV, exhibiting lower than a single MOF-derivative, promoting the adsorption of NH 3 or NO. The reaction mechanism on the M-MnCeO X catalyst followed the E-R and L-H mechanisms by In situ DRIFTS.
研究领域:
环境催化
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材料科学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2018
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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
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2019
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IF 3.131
Boqiong Jiang,Beilong Lin,Zhiguo Li,Shuang Zhao,Ziying Chen
A series of Mn/TiO 2 catalysts were prepared by ultrasonic spray pyrolysis (USP) method for selective catalytic reduction (SCR) of NOx from flue gas at low temperatures. The highest activity of Mn/TiO 2 was obtained with a Mn/Ti ratio of 0.5. When Fe was doped into Mn(0.5)/TiO 2 , the NOx conversion rate on Fe(0.05)-Mn(0.5)/TiO 2 was increased by approximately 10 % at 120–180 °C. The samples were characterized by XRD , SEM , H 2 -TPR, and N 2 adsorption analyses. Results revealed that Mn(0.5)/TiO 2 with Mn/Ti ratio of 0.5 presented the lowest crystallinity , the highest surface area, and the highest redox ability. Although the surface area was significantly decreased by Fe doping, it also reduced the crystallinity and crystal size of the catalysts, thereby increasing the O concentration on the surface of catalyst. Moreover, Fe(0.05)-Mn(0.5)/TiO 2 displayed a higher redox ability than the other catalysts. At 120–240 °C, the activation energy decreased from 27.65 kJ/mol on Mn(0.5)/TiO 2 to 14.46 kJ/mol on Fe(0.05)-Mn(0.5)/TiO 2 , thereby facilitating the activation of the reaction on Fe(0.05)-Mn(0.5)/TiO 2 . Despite that the NO and NH 3 adsorptions were lower on Fe(0.05)-Mn(0.5)/TiO 2 than on Mn(0.5)/TiO 2 , the intermediates on Fe(0.05)-Mn(0.5)/TiO 2 , particularly nitrates, were easily activated to participate in the reaction, leading to increasing catalytic activity.
研究领域:
环境科学
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催化材料
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产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2021
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IF 7.963
Ji Liu,Wei Zhao,Shuang-wei Yang,Bin Hu,Ming-xin Xu,Shan-Wei Ma,Qiang Lu
Incineration of food waste leads to the release of NO x pollutants, whereas the formation mechanism of the NO x precursors (HCN, NH 3 , and HNCO) during the initial pyrolysis process is far from well-studied, limiting the source control on NO x release. In this work, 2,5-diketopiperazine (DKP) was selected as the N-containing model compound to study the formation mechanism of NO x precursors in food waste pyrolysis, by combining experiments and density functional theory (DFT) calculations. The C1-N2 bond broken via the N2-to-N5 H-transfer possesses the lowest energy barrier, together with the largest reaction rate constants in the range of 400–800 °C. NH 3 can be easily generated with low energy barriers and high rate constants at low temperatures (below 630 °C). Whereas, the rate constants of the pathways for HCN formation will exceed those for NH 3 generation in the range of 630–740 °C. In addition, the DKP pyrolysis can also lead to the formation of HNCO with a very low energy barrier, and it can convert into HCN and NH 3 through further hydrogenation and decomposition. These calculation results are exactly consistent with the experimental results that NH 3 was the main precursor in the range of 400–600 °C, and the yield of HCN exceeded that of NH 3 when the temperature was over 600 °C. Our current work on the formation mechanism of NO x precursors during the pyrolysis of DKP can provide theoretical guidance for the development of NO x control technology in the pyrolysis/combustion process of organic waste.
研究领域:
环境科学
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化学工程
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能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
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2022
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IF 7.968
Nan Ma,Zhifei Hao,Guoquan Liu,He Zhang,Sihui Zhan
Acidity is a crucial factor limiting the application of ceria-based catalyst for selective catalytic reduction (SCR) of NO x with NH 3 . Unravelling the participation mechanism of acid sites on ceria-based catalyst is imperative but still lacking. Herein, by tuning the electronic interaction between MoO x and CeO 2 nanosheet with numerous pits (P-CeO 2 ) via controlling the number of surface pits of P-CeO 2 , we demonstrate that electronic interaction strongly determines the acidity properties of catalyst to modulate the catalytic performance. The MoO x /P-CeO 2 exhibits much better catalytic activity , N 2 selectivity and tolerance to SO 2 and H 2 O than MoO x /CeO 2 with few pits in a temperature range of 250–400 °C with a gas hourly space velocity (GHSV) of 60,000 h −1 , which is due to the highly dispersion of Mo-O-Mo structure over P-CeO 2 as determined by Raman. Furthermore, XPS and DFT calculations demonstrate that electrons transfer from P-CeO 2 to MoO x result in a unique dynamic transformation from Brønsted acid site to Lewis acid site, enhancing the catalytic activity. This work increases the acidity sites on the catalyst by regulating the electron oxide-support interaction, which provides a new strategy for designing highly efficient ceria-based SCR catalysts.
研究领域:
催化化学
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环境科学
✓ 已验证
DOI
高影响因子
ACS Sensors
·
2025
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IF 9.1
Weirong Zhou,Guoxuan Gu,Yuan Gao,Jiayin Han,Ning Yu,Chao Liao,Geyu Lu
Monitoring trace levels of nitrogen oxides (NOx) in high-humidity agricultural greenhouse environments is essential for both crop growth and workers’ health. However, achieving reliable NOx detection under extreme humidity remains challenging. Herein, this work presents an ultralow-detection-limit and highly humidity-tolerant NOx sensor based on Ag2Te/CeO2 nanocomposites. To the best of our knowledge, this is the first demonstration of Ag2Te/CeO2 heterostructures for gas sensing. Among the as-prepared samples, the optimal Ag2Te/CeO2 sample, with a molar ratio of 1:2, exhibited superior response and an ultralow detection limit of 5 ppb NO2 at 65 °C. The sensor response retained over 92% of its regular response even at 99% relative humidity. Density functional theory (DFT) calculations suggest that minimal H2O adsorption on Ag2Te and strong NO2 adsorption on CeO2, along with the formation of an n–n heterojunction, synergistically enhanced performance. Moreover, the sensor was further integrated into an Internet of Plants (IoP) environmental monitoring system. This work provides a new strategy for designing humidity-tolerant NOx sensors and offers a core device for smart agriculture.
研究领域:
材料科学
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环境科学
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农业技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2024
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IF 12.2
Fuli Wang,Aling Chen,Tianwei Lan,Xin Chen,Mengxue Wang,Xiaonan Hu,Penglu Wang,Danhong Cheng,Dengsong Zhang
The synergistic removal of NO x and chlorinated volatile organic compounds (CVOCs) has become the hot topic in the field of environmental catalysis. However, due to the trade-off effects between catalytic reduction of NO x and catalytic oxidation of CVOCs, it is indispensable to achieve well-matched redox property and acidity. Herein, synergistic catalytic removal of NO x and chlorobenzene (CB, as the model of CVOCs) has been originally demonstrated over a Co-doped SmMn 2 O 5 mullite catalyst. Two kinds of Mn-Mn sites existed in Mn-O-Mn-Mn and Co-O-Mn-Mn sites were constructed, which owned gradient redox ability. It has been demonstrated that the cooperation of different active sites can achieve the balanced redox and acidic property of the SmMn 2 O 5 catalyst. It is interesting that the d band center of Mn-Mn sites in two different sites was decreased by the introduction of Co, which inhibited the nitrate species deposition and significantly improved the N 2 selectivity. The Co-O-Mn-Mn sites were beneficial to the oxidation of CB and it cooperates with Mn-O-Mn-Mn to promote the synergistic catalytic performance. This work paves the way for synergistic removal of NO x and CVOCs over cooperative active sites in catalysts.
研究领域:
环境催化
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材料科学
✓ 已验证
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2023
·
IF 8.8
Guobo Li,Yaping Zhang,Peng Wu,Kai Shen,Shule Zhang,Shipeng Ding
The synergistic degradation of VOCs and NO x that were emitted from the incineration of municipal and medical wastes by a single catalyst is challenging, due to the poor activity at low temperatures, and the SO 2 poisoning on the active sites. Herein, N-doped TiO 2 (N–TiO 2 ) was used as the support for designing a highly efficient and stable catalyst system for CB/NO x synergistic degradation even in the presence of SO 2 . The prepared SbPdV/N–TiO 2 catalyst, which presented excellent activity and tolerance to SO 2 in the CBCO + SCR process, was investigated by a series of characterizations (such as XRD, TPD, XPS, H 2 -TPR and so on) as well as DFT calculations . The electronic structure of the catalyst was effectively modulated after N doping, resulting in effective charge flow between the catalyst surface and gas molecules. More importantly, the adsorption and deposition of sulfur species and reaction transient intermediates on active centers were restrained, while a new N adsorption center for NO x was provided. Abundant adsorption centers and superior redox properties ensured smooth CB/NO x synergistic degradation. The removal of CB mainly follows the L-H mechanism, while NO x elimination follows both E-R and L-H mechanisms. As a result, N doping provides a new approach to develop more advanced anti-SO 2 poisoning CB/NO x synergistic catalytic removal systems for extensive applications.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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