ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2024
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IF 10.8
Yunshuo Wu,Xuanhao Wu,Jie Fan,Haiqiang Wang,Zhongbiao Wu
Iron zeolites are promising candidates for mitigating nitrous oxide (N2O), a potent greenhouse gas and contributor to stratospheric ozone destruction. However, the atomic-level mechanisms by which different iron species, including isolated sites, clusters, and particles, participate in N2O decomposition in the presence of CO still remain poorly understood, which hinders the application of the reaction in practical technology. Herein, through experiments and density functional theory (DFT) calculations, we identified that isolated iron sites were active for N2O activation to generate adsorbed O* species, which readily reacted with CO following the Eley–Rideal (E-R) mechanism. In contrast, Fe2O3 particles exhibited a different reaction pathway, directly reacting with CO to generate oxygen vacancies (Ov), which could efficiently dissociate N2O following the Mars-van Krevelen (MvK) mechanism. Moreover, the transformation of iron oxide clusters into undercoordinated FeOx species by CO was also revealed through various techniques, such as CO-temperature-programmed reduction (TPR), and ab initio molecular dynamics (AIMD) simulations. Our study provides deeper insights into the roles of different iron species in N2O-SCR by CO, and is anticipated to facilitate the understanding of multicomponent catalysis and the design of efficient iron-containing catalysts for practical applications.
研究领域:
催化化学
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环境科学
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材料科学
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DOI
PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
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2023
·Vol. 47
·期 42
·19688-19697
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IF 3.3
Yang Zou,Xue Li,Siqi Hu,Yumeng Wen,Xiaolong Liu,Chunxin Lu,Tingyu Zhu
Four types of Pt/C catalysts were synthesized by depositing platinum on various carbon materials, including graphene, graphitic carbon nitride, activated carbon, and carbon nanotubes. The microscopic structure and physicochemical properties of these catalysts were analyzed using different techniques such as TEM, XRD, BET, TGA, and XPS. The results indicated that platinum predominantly existed in the form of nanoparticles on graphene, graphitic carbon nitride, and carbon nanotubes. The performance of the catalysts in catalyzing CO oxidation was evaluated, and Pt/CNTs exhibited the highest efficiency compared to other catalysts. At a temperature of 170 °C, the conversion efficiency of CO on Pt/CNTs reached 96.5%. In situ DRIFTS experiments were performed, which did not show any peaks of CO adsorption on the surface of Pt/CNTs. Therefore, the oxidation of CO on Pt/CNTs was presumed to proceed via the Eley–Rideal (ER) mechanism. O2 was adsorbed and activated on Pt NPs to form a Pt NP–O–O*–CO structure with CO, which then decomposed to yield CO2 and an activated oxygen species (O*). Finally, O* reacted with CO again to produce CO2, completing the catalytic cycle.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2024
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IF 3.8
Kaiqi Wang,Bo Lin,Wende Xiao
A coprecipitation approach was used to prepare vanadium–molybdenum composite oxide catalysts, which were then calcined at 300, 400, 500, 600, and 700 °C. The vanadium–molybdenum catalyst, under calcination at 500 °C, possesses abundant surface defects and acid species. As a result, it showed an outstanding active window, achieving over 90% NOx conversion efficiency within the temperature range of 220–340 °C. Compared with other catalysts, the vanadium–molybdenum catalyst with the calcination at 500 °C resulted in the formation of polymeric vanadate with the most active oxygen, which was conducive to the high catalytic efficiency for the NH3-SCR reaction. Based on our in-depth understanding gained from in situ DRIFTS experiments, we proposed that the NH3-SCR reaction occurred on the vanadium–molybdenum catalyst via an Eley–Rideal pathway. This mechanism involves the initial adsorption of ammonia on the catalytic surface, followed by its interaction with weakly adsorbed or gaseous NO to form an activated complex. Furthermore, the presence of molecular oxygen (O2) serves to augment the adsorption and activation of nitric oxide over the catalytic surface. The augmentation arises from the generation of adsorbed NO2 species or nitrates, which possess pronounced oxidizing capabilities. Notably, the significant impact of NH3 and NO in the denitration reaction was elucidated, providing valuable insights that can guide the adjustment and optimization of practical operational conditions. This understanding is crucial for enhancing the efficiency and effectiveness of the denitration process, thereby contributing to improved environmental qualities.
研究领域:
环境科学
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催化化学
✓ 已验证
DOI
高影响因子
ACS Sensors
·
2024
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IF 8.2
Wei Zhang,Zhenyu Yuan,Hongmin Zhu,Shouwen Zhang,Fanli Meng
This study presents a comprehensive kinetic investigation for describing the dynamic sensing process of semiconductor metal oxide (SMO)-based gas sensors, with a focus on the Eley–Rideal mechanism as a valid pathway. The modeling elucidates the direct interactions between volatile organic compounds (VOCs) and adsorbed oxygen on the material surface, providing insights into the temperature-dependent response characteristics of the sensor and addressing selectivity toward different VOCs fundamentally. By incorporating the effects of thermal modulation, the kinetic model was validated through theoretical fitting of experimental data obtained from a fabricated SnO2 nanoparticle gas sensor exposed to ethanol, n-propanol, toluene, and butanone at systematically varying operating temperatures. The results demonstrated that the model accurately captures response transient values, enabling a general framework for qualitatively discriminating specific gases based on their unique reaction kinetics. Furthermore, a machine learning procedure containing the above model and power laws of quantitative concentrations after identifying compounds was developed for the prediction of target VOCs. The qualitative accuracy was determined to be 99.4%, while quantifying with the mean absolute errors of 5.0, 7.5, 4.0, and 8.9 within the range of 25–200 ppm, respectively. The precise and straightforward strategy facilitates the response modeling of SMO-based gas sensors, offering a valuable platform for the designing model-driven algorithms applicable in gas analysis and monitoring.
研究领域:
材料科学
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化学工程
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机器学习应用
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产品关联
DOI
PubMed
高影响因子
FUEL
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2022
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IF 8.035
Xiaodi Li,Shan Ren,Lian Liu,Xiangdong Xing,Lin Chen,Jiangling Li,Jian Yang,Qingcai Liu
The serious deactivation of denitration catalysts caused by heavy metals still a thorny issue in the practical application of selective catalytic reduction of NO x with NH 3 . Herein, we proposed a novel anti-poisoning strategy by designing SO 4 2− /ZrO 2 superacid supported CeO 2 /ZrO 2 catalyst, and the effect of SO 4 2− /ZrO 2 supported CeO 2 /ZrO 2 for PbO-resistance NO x catalytic reduction was investigated. It was worthy to note that the introduction of solid superacid SO 4 2− /ZrO 2 significantly enhanced catalytic performance over the entire temperature range, with an exceptionally high NO x removal efficiency over 98 % during 250–500 °C. When 2 wt% PbO was deposited on the fresh catalyst, the catalytic activity of CeO 2 /ZrO 2 catalyst decreased obviously, while CeO 2 /ZrO 2 -S catalyst can still maintain a higher NO x conversion over 90 % from 275 to 500 °C. The characterization results confirmed that the introduction of solid superacid SO 4 2− /ZrO 2 enhanced the surface acidity and promoted the transformation from Ce 4+ to Ce 3+ . The results of in situ DRIFTS implied that the Eley-Rideal (E-R) mechanism was obeyed over CeO 2 /ZrO 2 catalyst, and both Eley-Rideal (E-R) and Langmuir-Hinshelwood (L-H) mechanisms were followed over CeO 2 /ZrO 2 -S catalyst in the SCR process. With regard to poisoned catalysts, the NH 3 adsorption was inhibited to some extent, while the reaction mechanism wasn’t changed by PbO poisoning.
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
Tungsten
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2024
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IF 5.6
Zhang Zhi-Qi,Yang Liu,Luo Wen,An Vladimir,Li Jing,Liu Bao-Dan
The design and synthesis of vanadium-based denitration catalysts with low-temperature activity pose significant challenges in the field of toxic gas catalysis. In this study, we have developed a novel approach to fabricate highly efficient V 2 O 5 -WO 3 /TiO 2 monolithic mesh catalysts for NO x reduction at low temperatures. First, TiO 2 nanosheets with strong adhesion and large surface area were grown on Ti mesh using plasma electrolytic oxidation technology and hydrothermal method. Then, super-small traces of WO 3 and V 2 O 5 active nano-species were subsequently deposited on TiO 2 nanosheets using the deposition–precipitation method. Compared to traditional ceramic-based V 2 O 5 -WO 3 /TiO 2 catalysts, our V 2 O 5 -WO 3 /TiO 2 monolithic mesh catalyst exhibits superior mechanical performance, excellent thermal conductivity, lower pressure drop, higher utilization of active components, and stronger synergistic effects. Significantly, the V 2 O 5 -WO 3 /TiO 2 monolithic mesh catalysts exhibited excellent low-temperature catalytic activity with 98% of NO x conversion at 220 ℃, and remarkable long-term SO 2 tolerance and water resistance in the selective catalytic reduction (SCR) of NO x with NH 3 . The SCR reaction of tiny V 2 O 5 and WO 3 active species supported on TiO 2 nanosheets directly demonstrated to follow the Eley–Rideal mechanism by in situ infrared spectra.
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
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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
RESEARCH ON CHEMICAL INTERMEDIATES
·
2022
·Vol. 48
·期 6
·2627-2640
·
IF 3.134
Wang Guangying,Liang Yan,Song Jian,Xu Kui,Pan Youchun,Xu Xiaolong,Zhao Yu
Co-doped MnCeO x /ZrO 2 catalysts were synthesized by impregnation method and their low temperature deNOx performance were evaluated. The physicochemical properties of the catalysts were studied. The results showed that the doped Co could promote the deNOx performance of MnCeO x /ZrO 2 significantly, and the doped catalyst with the Co/Mn molar ratio of 1:2 possessed the best catalytic performance. Compared with pure MnCeO x /ZrO 2 catalyst, the deNOx efficiency of the optimal 1Co 2 MnCeO x /ZrO 2 was higher to 93% at 100 °C, improved nearly by 17%. The complete removal of NO was achieved at the temperature range of 120–250 °C. The promoted catalytic performance of Co-doped MnCeO x /ZrO 2 catalyst was mainly attributed to the improvement of the catalyst support structure and surface acidity by Co. The catalytic reaction of NO with NH 3 over 1Co2MnCeO x /ZrO 2 catalyst follows both Eley–Rideal mechanism and Langmiur–Hinshelwood mechanism.
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
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
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
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
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