RSC Advances
·
2017
·Vol. 7
·期 60
·37787-37796
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IF 3.108
Xuesong Liu,Xiaodong Wu,Duan Weng,Zhichun Si,Rui Ran
Cu/SAPO-34 catalysts were prepared by wet impregnation and ion-exchange methods, and both the catalysts were hydrothermally treated at 750 °C in 10 vol% H2O/air for 24 h. Subsequently, the as-received and hydrothermally treated catalysts were exposed to a sulfur poisoning treatment at 350 °C in 100 ppm SO2/10 vol% H2O/air for 24 h and examined for NOx conversion. Sulfur poisoning considerably decreased the NOx conversion efficiency of the catalysts at low temperatures. In contrast, it improved the high-temperature selective catalytic reduction (SCR) activities of the as-received catalysts. The ion-exchange-prepared catalysts displayed higher sulfur tolerance than the impregnation-prepared catalysts at 150–350 °C. The electron paramagnetic resonance, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy and H2-temperature-programmed reduction results showed that sulfur poisoning significantly influenced the migration of the copper species and thereby the amount of active isolated Cu2+. More dispersed CuSO4 was produced on the ion-exchange-prepared catalysts than on the impregnation-prepared catalysts after sulfur poisoning. The dispersed CuSO4 showed considerably higher SCR activity than the crystalline CuSO4. Both the dispersed CuSO4 and remaining isolated Cu2+ determined the low-temperature SCR behavior of the sulfur-poisoned catalysts.
研究领域:
催化化学
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环境科学
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DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2017
·
IF 3.387
Leiqing Hu,Jun Cheng,Yannan Li,Jianzhong Liu,Li Zhang,Junhu Zhou,Kefa Cen
Mixed matrix membranes with ionic liquids and molecular sieve particles had high CO 2 permeabilities, but CO 2 separation from small gas molecules such as H 2 was dissatisfied because of bad interfacial interaction between ionic liquid and molecular sieve particles. To solve that, amine groups were introduced to modify surface of molecular sieve particles before loading with ionic liquid. SAPO 34 was adopted as the original filler, and four mixed matrix membranes with different fillers were prepared on the outer surface of ceramic hollow fibers. Both surface voids and hard agglomerations disappeared, and the surface became smooth after SAPO 34 was modified by amine groups and ionic liquid [P 66614 ][2-Op]. Mixed matrix membranes with composites of amine-modified SAPO 34 and ionic liquid exhibited excellent CO 2 permeability (408.9 Barrers) and CO 2 /H 2 selectivity (22.1).
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
·
2019
·Vol. 2020
·期 3
·318-326
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IF 2.578
Mingjian Luo,Mingxu Liu,Yadong Fu,Wenxin Chen,Baohui Wang,Guoliang Mao
Graphical Three-stage SAPO-34s have higher purity, smaller crystal size, more acidic sites, longer catalytic lifetime and better olefin selectivity. The crystallization mechanism and the relationship between properties and performance are discussed. Acidity and 2–4 nm mesopores have little effect on MTO performance, which mainly depends on the size and dispersity of the crystallites and the purity of SAPO-34. SAPO-34 zeolites were synthesized by one-, two-, and three-stage crystallization processes with fumed silica (FS), acidic silica sol (AS), basic silica sol (BS) and tetraethoxysilane (TEOS) as silicon sources. Properties of samples were characterized by XRD, SEM, EDX, N 2 -adsorption/desorption, NH 3 -TPD and 29 Si NMR. In contrast with one- and two-stage processes, the three-stage one favors the formation of SAPO-34s with higher purity, higher Si/Al ratio, smaller crystallite/crystal size, better dispersion and more acidic sites. Crystallization mechanism was proposed. It is supposed that three-stage process favors the formation of high supersaturated SBUs (secondary building units) and CBUs (composite building units) before nucleation. Thus massive nuclei are formed during nucleation and well-dispersed small size SAPO-34 crystals are formed in three-stage process. Three-stage SAPO-34s are longer catalytic lifetime and better olefin selectivity in MTO process. TEOS-3 has the best MTO performance. It was found that acidity of sample and mesopores in 2–4 nm range have little effect on the MTO performance of SAPO-34. Catalytic lifetime and olefin selectivity are mainly depending on the size of crystallites, the dispersity of crystallites, and the purity of SAPO-34.
研究领域:
材料科学
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催化化学
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DOI
高影响因子
Green Energy & Environment
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2019
·
IF 0
Ge Li,Baodong Wang,Qi Sun,Wayne Qiang Xu,Ziran Ma,Hongyan Wang,Daojun Zhang,Jiali Zhou
A combined acid–alkali hydrothermal method was used to prepare fly ash –derived SAPO-34 molecular sieves from a thermal power plant in Inner Mongolia (China). The specific surface area of the prepared fly-ash-derived SAPO-34 molecular sieves was 579 m 2 g −1 , the total pore volume was about 0.27 cm 3 g −1 , and the pore size was 0.56 nm; the molar ratios of Al 2 O 3 :P 2 O 5 :SiO 2 were 1:0.86:0.45. Cu/SAPO-34 catalysts were prepared by impregnation of low-cost fly-ash-derived SAPO-34 molecular sieves as a support and tested in selective catalytic reduction with NH 3 (NH 3 -SCR). Powder X-ray diffraction (XRD), N 2 adsorption–desorption, X-ray photoelectron spectroscopy (XPS), H 2 temperature-programmed reduction (H 2 -TPR), NH 3 temperature-programmed desorption (NH 3 -TPD), electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), X-ray fluorescence analysis (XRF) and scanning electron microscopy (SEM) were used for catalyst characterization and investigation of the relationships between the catalyst structure and the catalytic activity. The actual silica:alumina ratio of the molecular sieves did not increase with increasing Cu loading, indicating that increasing the Cu loading does not change the original structure of the SAPO-34 molecular sieves. The XRF and NMR results showed that replacement by Cu results in more Si islands. The molecular sieve acidity decreased because of the increased number of Si islands. The NH 3 -TPD results showed that for the Cu/SAPO-34 catalysts there was a low correlation between the low-temperature activity and the amount of acidic sites. SCR activity is closely related to the location of Cu. The 4.47Cu/SAPO-34 catalyst has the highest isolated Cu 2+ showed the highest NH 3 -SCR activities (> 90%) at 250–350 °C. This work opens up new avenues for recycling fly ash formed in coal-fired power plants (reducing environmental pollution) and developing low-cost SCR catalysts for NO x pollution control.
研究领域:
环境科学
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材料科学
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产品关联
DOI
CATALYSIS LETTERS
·
2025
·Vol. 155
·期 3
·1-11
·
IF 2.4
Wen Chenglong,Liu Kang,Lu Yi,Wu Xintian,Li Shuning,Lu Mohong,Zhu Jie,Li Mingshi,Song Chunshan,Lu Xiaosong
Ni/SAPO-11 catalysts with highly dispersed Ni (TA-Ni/SA-11) were prepared using tartaric acid as a dispersant. The effect of the tartaric acid content on the physiochemical properties of the TA-Ni/SA-11 catalysts and their n-heptane hydroisomerization performance were investigated. TA-Ni/SA-11 exhibits smaller Ni particles and more Ni active sites in comparison to conventional Ni/SAPO-11 prepared via the impregnation method due to the interaction between tartaric acid and Ni 2+ . As the molar ratio of tartaric acid and Ni 2+ (n TA /n Ni ) increases, the number of Ni active sites in TA-Ni/SA-11 rises, while the surface area and relative crystallinity decrease because of the dealumination of SAPO-11. When n TA /n Ni is 0.75, 0.75TA-Ni/SA-11 presents the highest n-heptane conversion of 82.4% and isomer selectivity of 90.5%, as well as the lowest cracking selectivity of 9.0% at 380 °C, 1.5 MPa, 2 h − 1 , and a volume ratio of H 2 to n-heptane of 400 among these catalysts. Graphical
研究领域:
催化化学
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材料科学
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
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2017
·Vol. 52
·期 8
·4460-4471
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IF 2.599
Chen Zhou,Dong Yunyun,Jiang Shaoyang,Song Wenjing,Lai Weikun,Yi Xiaodong,Fang Weiping
Hierarchical SAPO-11 was successfully synthesized without a secondary template by changing the hydrothermal crystallization temperature. SAPO-11 with a larger external surface area, more acidity, and a large number of external active sites was constructed through a novel two-step crystallization strategy. Both precrystallization step and the low-temperature crystallization step were confirmed to be indispensable conditions for constructing hierarchical SAPO-11. After loading Pt nanoparticles by incipient wetness impregnation, the heptane hydroisomerizations based on 0.5 wt% Pt/C-SAPO-11-200 and 0.5 wt% Pt/T-SAPO-11-120 catalysts were carried out in a fixed-bed at a total pressure of 1.5 MPa with a H 2 /n-heptane volumetric of 400 and WHSV = 10 h −1 . A conversion level of 75.7% of 0.5 wt% Pt/T-SAPO-11-120 catalyst was reached, which was higher than that of 0.5 wt% Pt/C-SAPO-11-200 catalyst (64.3%) at 300 °C. The enhanced performance achieved was attributed to the improved effect of the support, in terms of not only better mass transport and higher number of exposure active sites but also improved dispersity and decrease in the size of Pt particles.
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
Clean Energy
·
2025
·
IF 3.7
Jiang Zhenhua,Xia Wei,Zhang Yanli,Wang Xinrui,Dong Mingyuan,Chen Kun,Liu Dong,Lu Baowang
This study aims to compare the catalytic performance of ZSM-5 and SAPO-34 zeolite catalysts in the conversion of ethanol. Through experiments conducted at different temperatures (773 K and 673 K), it was found that SAPO-34 initially exhibits superior propylene selectivity compared to ZSM-5. However, the propylene yield on SAPO-34 gradually decreases, while the ethylene yield increases with time on stream. density functional theory calculations were employed for the investigation of reaction mechanism. The results indicate that the SAPO-34 catalyst surface favors propylene desorption, which beneficial for its initial high propylene selectivity. Nevertheless, the smaller pore structure of SAPO-34 limits the effective diffusion of products, leading to product accumulation within the pores and potentially causing catalyst coking and deactivation. By combining the experimental results with theoretical calculation, this study not only explored the selectivity difference between SAPO-34 and H-ZSM-5 in ethanol conversion reaction, but also revealed the influence of different molecular sieve catalyst structures on product distribution and catalyst stability.
研究领域:
催化化学
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材料科学
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计算化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2024
·
IF 5.8
Xin Su,Chunquan Liu,Jing Liu,Guanyi Chen,Beibei Yan,Jingang Yao,Zhanjun Cheng,Weiming Yi
Arundo donax, acknowledged for its elevated energy content, substantial biomass yield and rapid growth, stands as an alluring candidate for biofuel production. In this investigation, a molecular sieve-based catalyst was utilized to scrutinize the catalytic fast pyrolysis (CFP) of Arundo donax, aiming for the production of naphtha-range compounds. The study also encompassed the evaluation of pyrolysis product yields within a fixed-bed reactor. The systematic exploration included an assessment of the impacts arising from catalyst type, temperature, weight hourly space velocity (WHSV), and N 2 flow rate. The results demonstrated that at 500 °C, WHSV of 1 h −1 and N 2 flow rate of 300 ml/min, SAPO-11 exhibited a selectivity of 64.55% to naphtha-range compounds and 64.55% to isomerous naphtha-range compounds. This was in stark contrast to the control group, which contained no catalyst (with a selectivity of 41.40% and 3.19%, respectively), SAPO-41 (with a selectivity of 11.02% and 9.55%, respectively) and HZSM-5 (with a selectivity of 59.89% and 53.51%, respectively). Additionally, SAPO-11 yielded the highest bio-oil compared to other catalysts (SAPO-11 of 28.52 wt% > none of 19.48 wt% > HZSM-5 of 18.90 wt% > SAPO-41 of 13.11 wt%). The conclusions drawn from these findings imply that the synthesized SAPO-11 catalyst exhibited superior catalytic activity and isomerization proficiency in contrast to other catalysts (SAPO-41 and HZSM-5). Remarkably, under the specified conditions of SAPO-11 catalyst, temperature = 500 °C, WHSV = 1 h −1 and N 2 flow rate = 200 ml/min, the CFP process yielded a remarkable maximum absolute yield of the naphtha-range compound at 25.82 wt%, with an isomerized naphtha-range compound absolute yield of 25.35 wt%.
研究领域:
能源植物学
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催化化学
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DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2018
·Vol. 15
·期 6
·1490-1501
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IF 1.165
Xiangli Kong,Minghui Qiu,Anran Wang,Lu Yang,Rongfei Zhou,Yiqun Fan,Deshuang Kong,Changjun Gu
The adhesion and cohesion between the coating layers and the ceramic honeycombs are usually one of the key issues in the preparation of high-performance zeolite-based/Monolith catalysts. In this work, we investigate the deposition of high-efficiency Cu-SAPO-34 catalyst on a cordierite monolith with special focus on the impact of alumina binders on the structure, mechanical adhesion and cohesion, and catalytic performance of the monolithic catalyst. Two kinds of alumina nanoparticles, α-alumina and γ-alumina, have no significant impacts on the Cu-SAPO-34 crystal structure, micropore morphology and catalytic activity. But washcoating experiments showed that the mass loss rate of the coating was less and the loading of the catalyst was higher when α-alumina was used as the binder. The reason of improving the adhesion and cohesion strength is the suitable thermal shrinkage, the uniform distribution and densification structure of α-alumina. Furthermore, optimization of the coating formulation with α-alumina as the binder has been performed. Finally, the catalyst prepared under the optimal conditions was tested by SCR and a maximum conversion rate of 97.4% was obtained. It was concluded that the use of the washcoating method with α-alumina does not affect catalytic performance while it increases bonding strength between substrate and catalysts.
研究领域:
化学工程
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催化材料科学
✓ 已验证
DOI
高影响因子
Materials
·
2019
·Vol. 12
·期 23
·3948
·
IF 2.972
Lingfang Qiu,Zhiwei Zhou,Mengfan Ma,Ping Li,Jinyong Lu,Yingying Hou,Xiangshu Chen,Shuwang Duo
Novel visible-light responded aluminosilicophosphate-5 (SAPO-5)/g-C3N4composite has been easily constructed by thermal polymerization for the mixture of SAPO-5, NH4Cl, and dicyandiamide. The photocatalytic activity of SAPO-5/g-C3N4is evaluated by degrading RhB (30 mg/L) under visible light illumination (λ > 420 nm). The effects of SAPO-5 incorporation proportion and initial RhB concentration on the photocatalytic performance have been discussed in detail. The optimized SAPO-5/g-C3N4composite shows promising degradation efficiency which is 40.6% higher than that of pure g-C3N4. The degradation rate improves from 0.007 min−1to 0.022 min−1, which is a comparable photocatalytic performance compared with other g-C3N4-based heterojunctions for dye degradation. The migration of photo-induced electrons from g-C3N4to the Al site of SAPO-5 should promote the photo-induced electron-hole pairs separation rate of g-C3N4efficiently. Furthermore, the redox reactions for RhB degradation occur on the photo-induced holes in the g-C3N4and Al sites in SAPO-5, respectively. This achievement not only improves the photocatalytic activity of g-C3N4efficiently, but also broadens the application of SAPOs in the photocatalytic field.Keywords:g-C3N4;SAPO-5;composite;photocatalytic;visible light
研究领域:
材料科学
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环境科学
·
化学
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产品关联
DOI
PubMed
高影响因子
Inorganic Chemistry Frontiers
·
2022
·Vol. 9
·期 15
·3679-3691
·
IF 7.779
Lei Fan,Lianming Zhao,Yuchao Lv,Tinghu Wang,Yupeng Tian,Jianye Fu,Xinmei Liu
The synthesis of highly-dispersed non-noble metal based catalysts and their application in hydrogenation/dehydrogenation still remain challenging. Therefore, it is of great importance to protect metals from aggregation in both calcination and reduction processes. In this research, density functional theory (DFT) calculations were used to elucidate the stabilization effect of ionic liquid [Bmim][BF4] on Ni in the reduction process, showing that [Bmim][BF4] could efficiently inhibit Ni aggregation on the support. By further analysis combined with theoretical calculations, we found that the degree of metal dispersion before reduction directly determines the effect of [Bmim][BF4]. Guided by the DFT results, the method of co-assisted preparation of Ni/SAPO-11 using [Bmim][BF4] and lysine was adopted. Lysine forms a coordination compound with nickel oxides. The steric hindrance generated by the Ni–lysine complex can effectively inhibit the aggregation of nickel oxides during the calcination process. The DFT calculations revealed that during the reduction process, [BF4−] plays a dominant role in stabilization and electronic modulation by directly interacting with Ni on the support. The combination effects of [Bmim][BF4] and lysine effectively inhibit metal aggregation, leading to ultra-small nickel particles with a mean size of 4.4 nm over the obtained catalyst. Furthermore, the presence of [Bmim][BF4] also tunes the electronic state of Ni species. Using hexane isomerization as a probe reaction, the result indicates the excellent catalytic activity of the obtained catalyst (≈93.7% isomer selectivity at 63.5% conversion), much superior to that of Ni/SAPO-11 obtained from the traditional impregnation route (≈75.8% isomer selectivity at 64.6% conversion). This work provides a new method for the preparation of highly effective non-noble metal supported catalysts.
研究领域:
催化化学
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材料科学
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理论计算
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产品关联
DOI
高影响因子
ACS Catalysis
·
2021
·
IF 13.084
Yuebing Xu,Wenda Yu,Hao Zhang,Jian Xin,Xiaohui He,Bing Liu,Feng Jiang,Xiaohao Liu
Various Co-based SAPO-34 catalysts were prepared using different methods, including ion exchange (IE), incipient-wetness impregnation (IWI), and solid-phase grinding (SPG), to correlate the chemical states of Co species with the C–H and C–C bond scissions in ethane dehydrogenation. The IE-prepared Co/SAPO-34 led to stable, unreducible, and isolated exchanged Co sites anchored on the zeolite framework with a structure of −AlF–O–Co–O– and showed the highest selectivity to ethylene of close to 98% at 600 °C, which suggests that these Co sites favors suppressing the C–C bond scission in ethane. In comparison, the IWI- and SPG-prepared Co/SAPO-34 catalysts, especially for those with a high Co loading, inevitably give Co oxide clusters that are easily reduced into metallic Co. Together with catalytic results, characterizations, and DFT calculations, it is confirmed that the reduced Co clusters, especially for those outside SAPO-34 channels without the confinement effect, favor both C–H and C–C bond scission, boosting the conversion of ethane into CH4 or/and coke; however, the ionic-state −Co–O– species can smoothly terminate the ethane dehydrogenation for the ethylene product due to relatively high energy barriers for both C–H and C–C bond scission, avoiding a deep dehydrogenation and C–C cracking. As expected, the unreducible −Co–O– sites are very stable in the title reaction without deanchoring from the zeolite framework in a 100 h cyclic test. This study not only demonstrates the stable −Mδ+–Oδ− structure favorable for suppressing C–C bond scission but also highlights a catalyst-constructing strategy for Co-based and similar metal-based catalysts for dehydrogenation of other light alkanes.
研究领域:
催化化学
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材料科学
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计算化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）