Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Yanli Zhang,Jian Li,Jianyu Cai,Shuangye Li,Xing Fan,Liyun Song,Ruixue Guo,Jiasheng Liu
In this study, a series of γ-Fe 2 O 3 -modified V 2 O 5 -MoO 3 /TiO 2 (VMT) catalysts was prepared by wet impregnation method. The γ-Fe 2 O 3 -modified catalysts exhibited excellent catalytic performance, and 1.25 wt% γ-Fe 2 O 3 content improved the deNO x efficiency at 150 °C from 54% (unmodified VMT catalyst) to 84% (modified catalyst). BET, XRD, XPS, NH 3 -TPD, H 2 -TPR, and in situ DRIFTs were employed to characterize the physicochemical properties and reaction mechanisms of the catalysts. The introduction of γ-Fe 2 O 3 increased the V 5+ /V 4+ ratio, surface chemisorbed oxygen content, redox ability, and a number of acid sites in the prepared catalysts. XPS confirmed the addition of γ-Fe 2 O 3 introduced new charge transfer pathways (Fe 3+ /Fe 2+ ↔ V 5+ /V 4+ ). In situ DRIFTs suggested that the addition of γ-Fe 2 O 3 to the catalyst significantly increased the adsorption capacity of catalyst for NH 3 and NO x , while also exerting a strong activating effect on the adsorbed NH 3 . Furthermore, selective catalytic reduction over the VMT and 5PEG@1.25Fe-VMT catalysts followed the Eley-Rideal (E-R) mechanism. At temperatures above 200 °C, the 5PEG@1.25Fe-VMT catalyst also followed the Langmuir-Hinshelwood (L-H) mechanism.
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高影响因子
MOLECULES
·
2024
·Vol. 29
·期 16
·3747
·
IF 4.2
Guanyu Chen,Weixin Zhang,Rongshu Zhu,Yanpeng Chen,Minghu Zhao,Mei Hong
Zeolite-based catalysts efficiently catalyze the selective catalytic reduction of NOxwith methane (CH4-SCR) for the environmentally friendly removal of nitrogen oxides, but suffer severe deactivation in high-temperature SO2- and H2O-containing flue gas. In this work, SSZ-39 zeolite (AEI topology) with high hydrothermal stability is reported for preparing CH4-SCR catalysts. Mild acid leaching with oxalic acid (OA) not only modulates the Si/Al ratio of commercial SSZ-39 to a suitable value, but also removes some extra-framework Al atoms, introducing a small number of mesopores into the zeolite that alleviate diffusion limitation. Additional Co3O4modification during indium exchange further enhances the catalytic activity of the resulting In-Co3O4/H-SSZ-39(OA). The optimized sample exhibits remarkable performance in CH4-SCR under a gas hourly space velocity (GHSV) of 24,000 h−1and in the presence of 5 vol% H2O. Even under harsh SO2- and H2O-containing high-temperature conditions, it shows satisfactory stability. Catalysts containing Co3O4components demonstrate much higher CH4conversion. The strong mutual interaction between Co3O4and Brønsted acid sites, confirmed by the temperature-programmed desorption of NO (NO-TPD), enables more stable NxOyspecies to be retained in In-Co3O4/H-SSZ-39(OA) to supply further reactions at high temperatures.
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PubMed
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2025
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IF 5.4
Jian Gao,Xinrui Dai,Zhenhua Gu,Guixian Deng,Jiangyong Yuan,Kongzhai Li
Catalysts loaded with metal oxides of M (M = Mn, Co, Ce) were synthesized by deposition precipitation method using cold rolled sludge (iron oxide as the main component) as a raw material for the selective catalytic reduction of NO x by ammonia (NH 3 -SCR). Among the various formulations, the co-supported catalyst containing 5 % Mn and 5 % Co on CRS-400 exhibited exceptional SCR performance, achieving over 90 % conversion of NO x from 80 °C to 200 °C. The addition of 5 % Mn and 5 % Co as active components resulted in an increase in the specific surface area for catalytic performance and an enhancement of the redox capacity, leading to a significant improvement in catalyst activity. The catalyst’s efficient denitration performance was attributed to the synergistic interaction between Mn, Co, and Fe oxides, resulting in a catalyst with a higher proportion of adsorbed oxygen, as well as an elevated composition of Mn 4+ and Fe 2+ species. The catalyst demonstrated excellent SCR activity at low-temperatures, indicating its potential for downstream applications in soot treatment equipment. This would achieve the dual benefits of purifying the atmosphere and disposing of solid waste.
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ChemistrySelect
·
2024
·Vol. 9
·期 28
·e202401039
·
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.
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高影响因子
APPLIED SURFACE SCIENCE
·
2025
·
IF 6.9
Shibo Yu,Yiqing Zeng,Mengna Zhan,Shule Zhang,Zhaoxiang Zhong
The influence of phosphorus (P) on ammonia selective catalytic reduction (NH 3 -SCR) catalysts has been the subject of considerable scrutiny. Nevertheless, the precise mechanism of its influence remains a matter of contention. Furthermore, the impact of introducing P at varying stages during catalyst preparation process and its different sites within the catalyst structure on performance is frequently disregarded, significantly hindering practical guidance for designing effective modified catalysts. In this study, a series of P-modified CeO 2 /TiO 2 catalysts were synthesized by introducing P at different preparation stages, and various of characterization and comparison experiments were conducted to elucidate the effect of introducing P at different stages on NH 3 -SCR performance of NO x . Results show that introducing P before loading CeO 2 boosts catalyst activity, whereas delaying the introduction of P results in decreased activity and a progressive decline in catalyst performance as the sequence of P introduction is postponed. P introduced earlier tends to be distributed on the surface of the TiO 2 support, which contributes to the dispersion and anchoring of Ce species. In contrast, when the introduction of P was delayed, it tended to be distributed on the surface of the active species, which led to pore plugging and active sites being covered. Secondly, the variation in loading sites resulting from alterations in the stage of P introduction significantly affected on the chemical environment of Ce species, leading to notable differences in the redox capacity of the catalysts. This is the primary reason for the considerable discrepancy in the SCR performance of the catalysts. This study revealed the sensitivity of the stage of P introduction to CeO 2 /TiO 2 catalysts, providing new insights for designing modified CeO 2 /TiO 2 catalysts.
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Environmental Progress & Sustainable Energy
·
2025
·
IF 2.3
Zhengxiong Jiang,Zhitao Han
With the aim to develop wet denitration process for marine application, it is still challenging to simultaneously achieve high-efficiency NO x removal from flue gas and low nitrate concentration in scrubbed solution. Herein a novel two-step method was proposed to solve this issue: phosphate buffer solution (PBS) with organic additive was used to absorb NO x efficiently from flue gas, and in next step, Na 2 SO 3 as a reductant was added in the scrubbed solution to reduce NO x off-line. Five typical organic additives were chosen to compose with PBS. The tetrabutylammonium bromide and phosphate buffer solution (TBAB/PBS) composite solution exhibited superior NO x absorption performance. Furthermore, the effects of TBAB concentration, NO x oxidation degree, solution pH, temperature and O 2 concentration on NO x absorption performance of TBAB/PBS composite solution were investigated systematically, and a high NO x absorption efficiency of >90% could be achieved. It was mainly attributed to a physical complex between PBS and NO 2 , N O 3 − $$ N{O}_3^{-} $$ , N O 2 − $$ N{O}_2^{-} $$ , together with a mass transfer enhancement by TBAB. A long-run test showed that nitrate concentration was much lower than the limit value of IMO. Cyclic absorption and regeneration tests confirmed that Na 2 SO 3 could effectively regenerate the scrubbed solution in the absence of O 2 .
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Bo Feng,Tingman Zhao,Jiada Du,Jiyuan Hu,Yun Shi,Jingkai Zhao,Jianmeng Chen
Methane selective catalytic reduction (CH 4 -SCR) technology has shown promise for controlling NO x emissions from natural gas generator sets. This study presents a highly efficient Ce 30 In 15 /HBEA catalyst featuring dual active sites, Al-O – (InO + )-Si site for CH 4 activation and ceria oxygen vacancy (Ce 3+ -□) site for NO x activation. However, the CH 4 -SCR activity of this catalyst decreased in the presence of H 2 O, SO 2 , C 3 H 6 , and CO 2 . The inhibitory effects on CH 4 -SCR activity followed by the sequence: H 2 O > SO 2 > C 3 H 6 > CO 2 . In particular, H 2 O combined with Al-O – (InO + )-Si to form inactive In(OH) 3-z z+ species and occupied Ce 3+ -□, preventing Ce 4+ -NO 3 – /NO 2 – formation. In/Ce sulfate formation via the reaction between SO 2 and In/Ce active sites hindered CH 4 and NO x adsorption and activation. The formed carbon deposits covered the active sites on the catalyst surface due to incomplete C 3 H 6 oxidation . In comparison, the dual active sites were almost unaffected by CO 2 . Overall, this study provides a basis for the rational design of novel catalysts for CH 4 -SCR.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Jiafan Cheng,Weiman Li,Xiaoze Wang,Haidi Liu,Yunfa Chen
This work is dedicated to fabrication of catalytic fibers for the process of selective catalytic reduction of NO x by NH 3 (NH 3 -SCR). By employing vanadium-titanium as main catalytic components, we investigated the effect of different inorganic supports (glass fiber, aluminum silicate fiber and quartz fiber), preparation methods (a sol–gel method and a hydrothermal method) and loading weight of V 2 O 5 on the NH 3 -SCR performance of catalytic fibers. The catalytic aluminum silicate fiber with 5% vanadium/titanium ratio prepared by a sol–gel method (denoted as V5Ti/AF) showed the best SCR and mass transfer performance. Characterization results indicated that a relatively large surface area, strong acidity, well-dispersed catalyst particles, and good redox and desorption properties derived from the interaction between catalytic components and supports all contributed to the good performance of V5Ti/AF. The pressure drop of catalytic fibers were measured, and the total pressure drop of catalytic fibers and de-dust ceramic membranes was much lower than previously prepared catalytic ceramic membranes, indicating their potential use in the co-processing of dust and gaseous pollutants.
研究领域:
环境科学
·
材料科学
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 26
·期 13
·13602-13618
·
IF 2.914
Yue Huifang,Lu Pei,Su Wei,Xing Yi,Li Rui,Wang Jiaqing
To optimize the simultaneous removal of NO x and Hg 0 , a series of Cu a Ce b Zr c O 3 /γ-Al 2 O 3 catalysts prepared by the impregnation method were explored and their physical and chemical properties were analyzed by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, X-ray photoelectron spectroscopy (XPS), NH 3 -temperature-programmed desorption (NH 3 -TPD), H 2 -temperature-programmed reduction (H 2 -TPR), in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFT), and Fourier transform infrared spectroscopy (FT-IR). The results showed that 15% Cu 1.4 Ce 0.55 Zr 0.25 O 3 /γ-Al 2 O 3 resulted in the highest conversion efficiency for the simultaneous removal of NO x (93%) and Hg 0 (85%) at low temperatures (200 to 300 °C). Meanwhile, 15% Cu 1.4 Ce 0.55 Zr 0.25 O 3 /γ-Al 2 O 3 showed good stability and resistance to SO 2 and H 2 O, which is due to its low crystallinity, good textural performance, and strong redox ability. According to the TPD, TPR, and XPS results, the strong acidic character of 15% Cu 1.4 Ce 0.55 Zr 0.25 O 3 /γ-Al 2 O 3 promoted the removal of NO x and Hg 0 . The synergistic effect between CuO and CeO 2 in 15% Cu 1.4 Ce 0.55 Zr 0.25 O 3 /γ-Al 2 O 3 can increase the mobility of chemically adsorbed oxygen and activates lattice oxygen, leading to an excellent performance. The DRIFT results showed that NH 3 , NH 4 + , nitrate, and nitrite participated in the selective catalytic reduction (SCR) reaction. On the basis of our experimental results, Hg 0 and NO x removal mechanisms were proposed as Hg (ad) + O* → HgO (ad) and 2NH 3 /NH 4 + (ad) + NO 2 /NO 3 − (ad) + NO→2N 2 + 3H 2 O/2H + , respectively.
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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工业生态学
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高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2021
·
IF 9.028
Shuaiying Zhai,Yuetan Su,Xiaole Weng,Renna Li,Haiqiang Wang,Zhongbiao Wu
Vanadium-based catalysts have been extensively applied for the synergistic control of NOx and chlorinated organics. However, how the vanadia species affect the reaction activity and products distribution, and what are the dominant reaction sites of these vanadia species are still unknown. Herein, we investigated the reaction characteristics of monomeric and polymeric vanadate domains for the catalytically synergistic elimination of NOx and chlorobenzene (CB). Density functional theory (DFT) calculations and experimental investigations have been combined to clarify the effects of different vanadyl species on the synergistic reaction. It was noted that the main adsorption site of CB on the monomeric domain was V–OH bond, and that on the polymeric one was V═O bond. The monomeric vanadyl was favorable for converting the Lewis V═O into Brønsted V–OH, which provided sufficient H protons for HCl formation, whereas the polymeric species could effectively retain the V4+/V5+ redox cycle, and yielded superior activity in CB catalytic oxidation (CBCO) reaction. However, the abundant oxygen vacancies and the inclined accumulation of Cl by forming the V–Cl bands led to significant polychlorinated byproducts on the polymeric vanadyl catalysts. Our work gives the first insight into different vanadate domain effects on the synergistic reaction, and is expected to provide theoretical basis for efficient design of the vanadium-based catalysts toward multipollutants elimination.
研究领域:
催化化学
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环境化学
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材料科学
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计算化学
·
污染物控制
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高影响因子
Journal of Environmental Sciences
·
2026
·
IF 6.5
Zongyao Ying,Yingjie Wang,Xiaoyan Shi,Zidi Yan,Wenmiao Li,Yulong Shan,Yunbo Yu
Pd/SSZ-39 catalyst shows high performance for NO and C 2 H 4 adsorption even after hydrothermal aging at 850 °C. • Pd 2+ ions in Pd/SSZ-39 serve as active sites for both C 2 H 4 and NO adsorption. • In the co-existence of NO and C 2 H 4 , Pd/SSZ-39 preferentially adsorb NO while also retaining the ability to C 2 H 4 adsorption. In this work, Pd/SSZ-39 zeolite catalyst (an AEI-type) was studied as a passive NO x adsorber (PNA) and hydrocarbon trap aiming for cold-start emission control in diesel vehicles. The fresh and hydrothermally aged Pd/SSZ-39 were characterized by XRD, 27 Al NMR, H 2 -TPR, NO x -TPD and DRIFTS of CO adsorption to investigate the changes of zeolite structure and Pd species. The catalytic performance of fresh and hydrothermally aged catalyst in low temperature NO and C 2 H 4 adsorption were evaluated. Moreover, systematic PNA experiments under various conditions were conducted to study the NO and C 2 H 4 adsorption, as well as oxidation of C 2 H 4 and CO on Pd/SSZ-39. Moreover, the interaction of NO with CO or C 2 H 4 were studied by in situ DRIFTS experiments. Results demonstrate that Pd 2+ ions in Pd/SSZ-39 serve as the active sits for both C 2 H 4 and NO adsorption. In the gaseous mixtures of NO and C 2 H 4 , Pd 2+ ions in Pd/SSZ-39 tend to preferentially adsorb NO rather than C 2 H 4 . Both C 2 H 4 and CO act as a reducing component which enhances the NO adsorption and shifts the NO desorption to higher temperatures. Download: Download high-res image (237KB) Download: Download full-size image
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高影响因子
COMBUSTION AND FLAME
·
2021
·
IF 4.185
Ye Wu,Jian Mei,Tianyi Cai,Wei Wang,Hang Zhu,TianLi Sun,Dong Liu
Ammonia is considered to be a green energy due to its carbon-free footprint, high energy density, cheap transport costs and so on. However, the problem of NO x (mainly NO/NO 2 ) emissions especially at high temperature (>800 °C) inhibits the energy utilization progress of NH 3 (Such as NH 3 combustion). So, catalytic combustion of NH 3 is supposed to be a promising method to solve this problem but there is a rare report on that. The NO x emissions or N 2 selectivity performances in the NH 3 oxidation process with different catalyst was conducted with Density functional theory (DFT) and experimental studies. Results showed that, when Fe 2 O 3 was used as catalyst, the conversion efficiency of NH 3 was 96.2%, and the selectivity of N 2 was 97.7%, which was higher than oxidation of NH 3 without catalyst. DFT simulation showed that NH 3 and O 2 can be separately adsorbed on Fe (top) of Fe 2 O 3 (001), the adsorption of NH 3 and O 2 were enhanced when they were put on Fe (top) of Fe 2 O 3 (001) at the same time. Meanwhile, the length of inter-atomic bond increased thus creating oxygen vacancy , which promoted the oxidation of NH 3 . Finally, a Ni modified Fe-based catalyst (NiO10%/Fe 2 O 3 30%/Al 2 O 3 60%), full of oxygen vacancy (confirmed with X-ray photoelectron spectroscopy (XPS)), was fabricated with impregnation method. The adsorption of NH 3 and O 2 were further enhanced (confirmed by DFT simulation), the NH 3 conversion efficiency and the N 2 selectivity were stably improved to 96.8% and 100%.
研究领域:
化学工程
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环境科学
·
催化材料
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高影响因子
危险品化学品经营许可证（带存储）