INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Wenshuo Hu,Renzhi Zou,Yi Dong,Yu Zhang,Mingchu Ran,Qi Xin,Yang Yang,Hao Song,Weihong Wu,Shaojun Liu,Chenghang Zheng,Xiang Gao
Enhancement of the low-temperature (LT) performance of selective catalytic reduction (SCR) of NOx with NH3 has been a spotlight in environmental catalysis. Here, we use a bifunctional catalytic system mixing V–W/Ti with an oxidative component, i.e., MnOx/CeO2, to achieve both improved LT-SCR activity and N2 selectivity. An integrated approach of steady-state kinetic measurements, chemical trapping techniques, time-resolved in situ FTIR spectroscopy, and density functional theory (DFT) calculations reveals that such a synergistic enhancement is at a short distance and is significant when V–W/Ti and MnOx/CeO2 are in intimate contact. These findings further suggest a bifunctional LT-SCR pathway mediated by a short-lived, mobile nitrite-precursor intermediate, which is facilely generated on the oxidative component and then communicates with the adjacent SCR phase through reacting with the abundant NH3 adsorbates there. Assembling such a mechanism with commercial SCR catalysts, accordingly, acts as a promising way to enhance the LT-SCR performance.
研究领域:
环境催化
·
材料科学
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DOI
高影响因子
TALANTA
·
2025
·
IF 6.1
Rui Yang,Luji Yang,Jiahui Yang,Zhi-ang Li,Chengbin Zheng
Pollution caused by nitrogen oxides (NO x , mainly NO and NO 2 ) has attracted considerable attention due to its negative implications on the environment and human health. Herein, a novel, portable, and battery-operated system integrating a purge and trap (P&T) system with a miniaturized point discharge optical emission spectrometer ( μ PD-OES) was developed for monitoring atmospheric NO x . Among NO x , NO 2 can be selectively and directly absorbed by sodium hydroxide (NaOH) solution and converted to nitrite (NO 2 − ). In contrast to NO 2 , NO cannot be absorbed by NaOH and must be oxidized to NO 2 by KMnO 4 prior to its absorption. When NO 2 and NO x samplers were exposed simultaneously, NO can be calculated as the difference. The concentration of NO x in the air was determined by analyzing the NO 2 − . The obtained NO 2 − solution was purged with an argon carrier gas at a rate of 400 mL min −1 for 5 min to remove all the volatile organic compounds contained in the solution before reacting with cyclamate to generate volatile cyclohexene, which was efficiently isolated and preconcentrated by P&T. Subsequently, the cyclohexene was desorbed from the P&T unit and swept into the μ PD-OES for its detection under optimized conditions. The system demonstrated a detection limit of 0.02 ppbv (0.04 μg/m 3 ) for NO 2 , surpassing conventional methods. Precision expressed as the relative standard deviation (RSD, n = 11) was better than 3.5 %. The system was validated by analyzing two NO 2 standard gases and fourteen ambient air samples, and the obtained analytical results demonstrated its promising potential for rapid, sensitive, and precise NO x evaluation and monitoring.
研究领域:
环境科学
·
分析化学
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产品关联
DOI
PubMed
高影响因子
ATMOSPHERIC ENVIRONMENT
·
2026
·
IF 3.8
Shijie Liu,Jie Wang,Zhifei Wang,Feiyong Chen,Yusi Liu,Xiaofeng Wei,Youmin Sun,Zaifeng Wang,Guiqin Zhang
α-Pinene is a key precursor in the formation of secondary organic aerosols (SOA) in the atmosphere. SOA formation via atmospheric photooxidation of α-pinene under varying nitrogen oxides (NO x ) and ammonia (NH 3 ) concentrations was investigated in a laboratory smog chamber, with a focus on SOA mass concentration and chemical composition. The experimental results demonstrated that increasing NO x concentrations from 30 to 80 ppb reduced the α-pinene SOA yield from 15.5% to 9.0%. In contrast, the presence of NH 3 enhanced the SOA yield. The investigation revealed that the suppressive effect of NO x on SOA yield gradually weakened with increasing NH 3 concentration, whereas the promoting effect of lower NH 3 concentrations on SOA yield was more pronounced under lower NO x conditions. The chemical composition of SOA revealed that NH 3 promoted the formation of nitrogen-containing organic compounds (NOCs). Furthermore, NO x increased the abundance of nitrogen-containing functional groups within NOCs. A comparison of the volatile components of SOA indicated that the increase in volatile organic component (VOC) and intermediate-volatility organic component (IVOC) contents with increasing NO x concentration was responsible for the suppression of SOA formation. Furthermore, the enhancement of SOA yield by NH 3 was mainly attributed to the increase in IVOC and semi-volatile organic component (SVOC) contents. Overall, these results demonstrated that NH 3 and NO x exerted distinct effects on α-pinene-derived SOA formation. These findings provide valuable insights into the mechanism of SOA formation under complex pollution conditions involving the coexistence of NO x and NH 3 .
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高影响因子
Catalysts
·
2025
·Vol. 15
·期 10
·971
·
IF 4
Shaogang Wang,Pengxin Zeng,Ning Li,Yuansheng Yi,Yongsheng Qin,Xin Yu,Lei Liu,Qi Guo,Zijian Zhou
The narrow operating temperature window of commercial V-W/TiO2catalysts severely limits NOxremoval efficiency, especially during low-load boiler operations. To achieve broad-temperature NOxabatement, we developed Ce-M/Ti (M = Co, Fe, Mn, Mo) catalysts via a dual-site strategy. The temperatures required for 80% NO conversion (T80) were 302 °C for Ce-Mo/Ti, 372 °C for Ce-Fe/Ti, 393 °C for Ce-Mn/Ti, and 415 °C for Ce-Co/Ti. Among them, Ce-Mo/Ti exhibited the most favorable low-temperature activity, outperforming a commercial catalyst (324 °C). Its turnover frequency (3.12 × 10−3s−1) was 1.29 times higher. Combined physicochemical characterization and density functional theory (DFT) calculations further reveal the mechanism behind the enhanced dual-site synergy in Ce-Mo/Ti. In the Ce-Co, Ce-Fe, and Ce-Mn sites, weak orbital hybridization leads to limited charge transfer. In contrast, Ce-Mo/Ti exhibits stronger hybridization between the Ce 4f/5dand Mo 4dorbitals, which breaks the inherent limitation of the Ce-based (Ce3+/Ce4+) redox capability and enables reverse electron transfer from Mo to Ce. This distinctive electron transfer direction creates a unique electronic environment, activating an efficient redox cycle between Mo6+/Mo5+and Ce4+/Ce3+. This work offers a promising design strategy for dual-site catalysts with high NOxremoval efficiency over a wide temperature range.
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高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Pengxin Zeng,Zijian Zhou,Lei Liu,Xin Yu,Xiaowei Liu,Minghou Xu
Commercial V-W/TiO 2 catalysts are extensively applied for NO x emission control in coal-fired power plants. However, their limited operating temperature range and low active site utilisation significantly restrict NO x removal efficiency, particularly during boiler load fluctuations. This study introduces atomically dispersed Ce-V/TiO 2 catalysts synthesised using a dual-site coordination strategy, enhancing active site dispersion. This method addresses the limitations of low active site turnover frequency (TOF) and high energy barriers in rate-determining steps, resulting in an extended operating temperature range and improved NO x removal efficiency. Under identical conditions, Ce-V/TiO 2 achieved 90 % NO x conversion from 290 to 450 °C, a substantial increase over the commercial catalyst (365–425 °C). Additionally, Ce-V/TiO 2 exhibited a TOF of 3.58 × 10 − 3 s − 1 , 1.52 times higher than the commercial catalyst. Density functional theory (DFT) analysis demonstrated that Ce V synergy accelerates the Eley-Rideal rate-determining step by lowering the activation energy for NH 3 dissociation into -NH 2 , and reduces the energy barrier for -NHNO intermediate formation in the Langmuir-Hinshelwood pathway. This work overcomes poor low-temperature activity by leveraging Ce V synergy, offering a strategy for efficient NO x removal across a broad temperature range with selective catalytic reduction catalysts.
研究领域:
环境催化
·
材料科学
·
化学工程
·
理论化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Junjie Jiang,Yongqi Zhao,Xue Li,Xiaolong Liu,Tingyu Zhu
Nitrogen oxides (NO x ) and volatile organic compounds (VOCs) released from industrial sources react to generate pollutants such as O 3 through photochemical reactions. In order to realize the simultaneous removal of NO x and VOCs, this work provides a reaction site-isolation (RSI) catalyst with isolated reaction zones of toluene oxidation over Cu-Ce sites and NH 3 -SCR over V-W sites, respectively. Reaction site-isolation significantly weakens the impact of competitive adsorption between different reactants and reduces the formation of by-products during the reaction. The NO and toluene conversion both reached to 100 % at 275 ℃ and the catalyst demonstrated great sulfur resistance and stability. Characterization of the catalyst revealed that the interaction between Cu and Ce promoted the formation of oxygen vacancies, while the introduction of Cu increased the adsorption sites of toluene. Notably, DFT calculation and activation energy calculation reveal that the adsorption performance of active sites for reactant and the reaction activation energy required for reactions are different. Therefore, this work achieves adsorption and reaction co-induced bifunctional catalysis by isolating active sites.
研究领域:
环境科学
·
催化化学
·
材料科学
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产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2026
·
IF 9
Hanbo Shi,Nannan Zhang,Wei Guo,Tancheng Dong,Bihui Zhou,Lanlan Yu,Baojun Liu,Jincheng Mu
Birnessite-type δ-MnO 2 is a promising candidate for low-temperature NH 3 -SCR reaction owning to its excellent redox properties. However, its performance is severely hampered by the excessive oxidation state of Mn species, which induces strong NH 3 chemisorption and subsequent over-oxidation to NO x . Herein, phenylalanine-functionalized δ-MnO 2 nanosheets (MnO x -Phe) were developed, leveraging Phe's coordinating –NH 2 group to modulate surface properties of Mn species. The optimal MnO x -Phe-0.1 catalyst achieves ∼90% NO x conversion at 75 °C with a broad temperature window from 75 to 210 °C (GHSV = 50,000 h −1 ), representing a reaction rate 4.8 to 8.2 times greater than that of pure δ-MnO 2 . Additionally, the catalyst exhibits remarkable resistance against SO 2 and H 2 O. Comprehensive characterizations and density functional theory calculations reveal that Phe modification shifts down the d -band center of δ-MnO 2 from −1.22 eV to −2.78 eV, and attenuates the oxidation state of Mn species. This unique configuration suppresses the over-oxidation of NH 3 and weakens the interaction between catalyst and poisons, while promoting the activation of NH 3 to *NH 2 with a lower energy barrier, thus driving a desired Eley-Rideal pathway and endowing strong tolerance against SO 2 and H 2 O at low temperatures. This work provides a novel organic-inorganic hybrid strategy for designing robust low-temperature NH 3 -SCR catalysts with superior activity and poison resistance.
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DOI
高影响因子
CATALYSIS TODAY
·
2020
·
IF 5.825
Jinfeng Han,Caixia Liu,Qingling Liu,Shuangchun Lu,Yalian Bi,Xiaohan Wang,Mingyu Guo,Chunfeng Song,Na Ji,Xuebin Lu,Degang Ma,Zhenguo Li
Novel Al-rich OFF-CHA twin-crystal zeolite was synthesized by one-pot hydrothermal method, and applied in ammonia-selective catalytic reduction (NH 3 -SCR) after copper ion exchange. Results indicated that Cu content in Cu-OFF-CHA played a significant role in NH 3 -SCR reaction. The insufficiency of copper activity sites and the formation of CuOx were the main reasons affecting low and high temperature SCR activity of catalyst, respectively. Cu 3.1 -OFF-CHA, with the optimal copper content, demonstrated over 90 % NOx conversion and exhibited excellent N 2 selectivity in the range from 160 to 550 ℃. Further research verified that the SCR activity of Cu 3.1 -OFF-CHA maintained above 80 % in the temperature range from 180–450 °C after hydrothermal treatment 16 h. The reason might be that Cu 2+ in Cu-OFF-CHA was migrated from CHA to OFF sites after hydrothermal treatment, and Cu 2+ in OFF sites on Cu-OFF-CHA was more stable, resulting in less conversion of the active site to CuOx clusters. Cu-OFF-CHA has the potential to be applied in SCR after-treatment systems of diesel exhaust due to the excellent SCR activity and hydrothermal stability.
研究领域:
催化化学
·
环境化学
·
材料科学
·
化学工程
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DOI
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2025
·
IF 7.7
Wenyu Li,Hui Yu,Ming Yang,Xiangting Dong,Ying Yang,Tianqi Wang
Photosensitized metal oxide gas sensors have been a research hotspot in the field of gas sensors in recent years, the vast majority of related studies use the ultraviolet light as the excitation light source, there are relatively few related studies on the ceramic gas sensors using a single LED as the excitation light sources, and even fewer studies on using natural sunlight as the light excitation source. In this study, porous ZnO precursor particles were introduced into the channels of ZIF-8 to ensure the integrity of its skeleton after calcination, and ZnO/ZIF-8 derivative was prepared and used to construct gas sensors to detect NO x under the different excitation light source (the natural sunlight, 365 nm LED and xenon lamp). Compared with the test under darkness conditions, the operating temperature was reduced 70℃ under light excitation conditions, the gas-sensitive response of the gas sensor to 20 ppm NO x under the natural sunlight excitation was 7.48 times of the darkness conditions, and the measured detection limit was as low as 50 ppb. Under the excitation of natural sunlight, 365 nm LED or xenon lamp, the room temperature gas sensitive response to NO x gas could be achieved. The prepared gas sensor was used for the actual detection of NO x concentration in vehicle exhaust, which showed the attractive practicality and excellent detection sensitivity.
研究领域:
气体传感器
·
材料科学
·
环境监测
·
光电传感
·
纳米材料
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产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2021
·Vol. 11
·期 15
·5125-5134
·
IF 6.119
Yanke Yu,Xianfang Yi,Jiali Zhang,Zhaojian Tong,Changwei Chen,Mudi Ma,Chi He,Jinxiu Wang,Jinsheng Chen,Bingbing Chen
Non-vanadium-based catalysts with high SO2 tolerance are still interesting in selective catalytic reduction of NO by NH3 (NH3-SCR) and SO2 adsorption is the foremost step for the deactivation of catalysts. In order to alleviate the adsorption of SO2, we fabricated a series of rhenium (Re; without stable sulfate) supported TiO2 catalysts and studied their SO2 tolerance for the first time. Owing to suitable surface acidity and reducibility, ReOx/TiO2 catalysts exhibited satisfactory activity in a wide temperature range of 250–350 °C. As expected, experimental results and DFT calculations indicated that SO2 adsorption on ReOx/TiO2 catalysts was rather weak, thus the catalysts performed excellent SO2 tolerance in the NH3-SCR reaction. Moreover, in situ DRIFTS indicated that the NH3-SCR reaction on ReOx/TiO2 catalysts followed the Eley–Rideal mechanism and SO2 had little effect on the reaction mechanism. Our findings should provide new insights into the development of SCR catalysts with high SO2 tolerance.
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DOI
高影响因子
RSC Advances
·
2021
·Vol. 11
·期 39
·24144-24155
·
IF 3.361
Xingdong Yang,Jiyan Qu,Linxi Wang,Jianhong Luo
In an attempt to realize the efficient treatment of NOx, a mixed catalyst of Ti3+ self-doped TiO2−x and γ-Al2O3 was constructed by reducing commercial TiO2. The degradation effect on NOx was evaluated by introducing the mixed catalyst into a coaxial dual-dielectric barrier reactor. It was found that the synthesized TiO2−x could achieve considerable degradation effects (84.84%, SIE = 401.27 J L−1) in a plasma catalytic system under oxygen-rich conditions, which were better than those of TiO2 (73.99%) or a single plasma degradation process (26.00%). The presence of Ti3+ and oxygen vacancies in TiO2−x resulted in a relatively narrow band gap, which contributed to catalyzing deeply the oxidation of NOx to NO2− and NO3− during the plasma-induced “pseudo-photocatalysis” process. Meanwhile, the TiO2−x showed an improved discharge current and promoted discharge efficiency, explaining its significant activation effect in the reaction. Reduced TiO2−x could achieve an impressive degradation effect in a long-time plasma-catalysis process, and still maintained its intrinsic crystal structure and morphology. This work provides a facile synthesis procedure for preparing Ti3+ self-doped TiO2−x with practical and scalable production potential; moreover, the novel combination with plasma also provides new insights into the low-temperature degradation of NOx.
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DOI
PubMed
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2019
·Vol. 128
·期 2
·1065-1077
·
IF 1.428
Yu Qifan,Liu Xuesong,Chen Hongfeng,Liu Shuang,Jiang Peng
The regeneration mechanism of sulfated Cu/SAPO-34 catalysts in reducing atmospheres (5% H 2 /Ar and NH 3 /Ar at 600 °C) was investigated by using a series of characterization methods. Hydrogen regeneration improved the catalysts’ NH 3 -SCR activity from 150 to 550 °C remarkably, while ammonia regeneration exhibited relatively less obvious promotion effect. The TPR of hydrogen and EPR spectra data show that the regeneration process affects the amount and the coordination of the active isolated Cu 2+ species significantly. The desulfation increases the amount of isolated copper ions and improves the catalytic activity of SCR.
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高影响因子
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