Chemistry-An Asian Journal
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2019
·Vol. 14
·期 16
·2815-2821
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IF 3.698
Wei Li,Shuang Wang,Jinping Li
Graphical Be well supported ! Two BaCeO 3 supports with strong basic sites were synthesized by a co-precipitation route under different calcination temperatures. BaCeO 3 -a has a high basic density and Ru/BaCeO 3 -a has more oxygen vacancies, which are beneficial for the dissociation of N 2 . Therefore, the 1.25 % Ru/BaCeO 3 -a catalyst exhibits superior performance in ammonia synthesis (see figure). BaCeO 3 -a and BaCeO 3 -b, with strong basic sites, were synthesized by using a co-precipitation method at different calcination temperatures, and used as supports to evaluate their performance in ammonia synthesis. The ammonia synthesis rate with the 1.25 % Ru/BaCeO 3 -a catalyst is 24 mmol g −1 h −1 , which is higher than that of 1.25 % Ru/BaCeO 3 -b catalyst (18 mmol g −1 h −1 ) at 3 MPa and 450 °C. Moreover, the performance of the 4 % Cs-1.25 % Ru/BaCeO 3 -a catalyst was further improved to 28 mmol g −1 h −1 , and no sign of deactivation was observed after a reaction time of 120 h. The XPS and H 2 temperature-programmed reduction analyses indicated that the Ru/BaCeO 3 -a catalyst has more oxygen vacancies than the Ru/BaCeO 3 -b catalyst. In addition, the average Ru particle size of the Ru/BaCeO 3 -a catalyst is closer to 2 nm than the Ru/BaCeO 3 -b catalyst, which promotes the generation of B 5 -type sites (the active site for N 2 dissociation). The CO 2 temperature-programmed desorption analysis indicates that BaCeO 3 -a has a high basic density, which is beneficial for electron transfer to Ru and further facilitates the dissociation of N≡N bonds.
研究领域:
催化化学
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材料科学
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DOI
PubMed
高影响因子
FUEL
·
2025
·
IF 7.5
Huiyu Liu,Ying Qiu,Rui Shan,Jun Zhang,Haoran Yuan,Yong Chen
Catalytic fast pyrolysis (CFP) using bimetallic modified ZSM-5 enables efficient upcycling of polyethylene (PE). The present study demonstrates that alkaline sites significantly enhanced the mass transfer capacity of catalysts through generating fragmented structures, thus contributing to the selective regulation of thermal decomposition behavior of PE. Specifically, CuZn/ZSM-5 reduced decomposition temperature range by > 100 °C via enhanced chain-cracking and product transport. The synergistic effects of Cu 0 and alkaline sites derived from Zn species facilitated the cleavage of C–C bonds under a high heating rate, thereby accelerating the formation of olefin intermediates as well as promoting the aromatization within ZSM-5 channels. CuZn/ZSM-5 optimally combined highly dispersed metal sites, abundant strong alkaline sites, moderate acidic sites, and reinforced diffusion capacity, boosting low-temperature aromatics selectivity by 29.7 %, particularly for monocyclic aromatic hydrocarbons (MAHs). Despite the highest alkalinity of CuMg/ZSM-5, the permanent loss of weak alkaline sites at high temperatures resulted in weak capacity for aromatization. In addition, the plausible pathway for fast pyrolysis of PE into aromatics over CuZn/ZSM-5 was proposed.
研究领域:
化学工程
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材料科学
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DOI
高影响因子
Molecular Catalysis
·
2021
·
IF 5.062
Tao Yang,Wenzhi Li,Ajibola T. Ogunbiyi
This study was focused on investigating a novel catalytic system for the selective conversion of furfural to maleic acid (MA) in an aqueous system with hydrogen peroxide as an oxidant. A series of experiments that study the impacts of catalyst species, furfural concentration, catalyst dosage, reaction temperature, residue time, hydrogen peroxide concentration, excess water content, and solvent types on the oxidation of furfural to MA was carried out. The results showed that the co-existence of Br- and alkali sites might play a vital role in furfural oxidation, which could improve the MA yield remarkably. Under 90 °C for 3 h, 72.4 % MA yield was obtained with KOH and KBr as co-catalyst in an aqueous phase. Moreover, a possible reaction pathway of furfural oxidation was proposed on the basis of our reaction system.
研究领域:
化学工程
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催化反应
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DOI
高影响因子
Molecular Catalysis
·
2020
·
IF 3.687
Huahua Zhao,Huanling Song,Fangyuan Wang,Zhichao Miao,Lingjun Chou
In the present work, a new strategy was developed to fabricate strong basicity on mesoporous zirconia by in-situ preservation of carbon species originated from organic template during the thermal treatment of mesoporous ZrO 2 . The carbon species was maintained on mesoporous zirconia by calcination in N 2 prior to the introduction of base precursor KNO 3 . The decomposition temperature of KNO 3 to strongly basic site K 2 O was significantly reduced from higher than 650℃ to about 400℃ in the presence of carbon species, which fascinatingly converted the endothermic decomposition reaction to exothermic process. More importantly, the tetragonal ZrO 2 support with excellent mesostructure was well stabilized by the carbon species after introduction of K species. Therefore, K 2 O supported on mesoporous tetragonal zirconia (K 2 O/M-ZrO 2 -C) were successfully fabricated. The resultant mesoporous basic material presented good activity in the synthesis of dimethyl carbonate (DMC) and the DMC yield was 60.0 %, apparently higher than that (18.1 %) of the catalyst prepared without preserving carbon species (K 2 O/M-ZrO 2 ). The strong basicity and the uniform mesopores of the catalyst were suggested to be contributed to the high activity. The obtained results will provide some fundamental understanding and guidance for rational catalyst design.
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
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2022
·Vol. 29
·期 56
·84166-84179
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IF 5.19
Gao Panting,Li Yuran,Lin Yuting,Chang Liping,Zhu Tingyu
Catalytic hydrolysis of carbonyl sulfur (COS) from blast furnace gas is one of the keys to achieving ultra-low emission in the iron–steel industry. To improve the COS hydrolysis activity on γ-Al 2 O 3 catalyst at low temperature, catalysts with Fe or La as the active component were prepared by the impregnation method, the physical and chemical properties of the catalyst were characterized by ICP, XRF, XRD, BET, and TPD. The hydrolysis activity of COS and sulfur resistance ability on various catalysts were investigated in a fixed bed reactor combined with gas chromatography. The results show that the addition of Fe or La improves the COS hydrolysis activity due to the increase in alkaline sites on the catalyst surface. The roles of various alkaline sites on catalysts have been recognized. The weak alkaline center is the reaction site of COS hydrolysis, the middle and strong alkaline centers are the adsorption and oxidation sites of H 2 S. The Fe/Al 2 O 3 catalyst has higher hydrolytic activity and oxidative capacity for H 2 S removal due to forming more sulfate species on Fe. The La/Al 2 O 3 catalyst has higher hydrolysis efficiency in that H 2 S rapidly desorbs from the catalyst surface to the gas phase, and then, the activity of reaction sites is recovered. This provides an idea for the preparation of sulfur-resistant catalysts.
研究领域:
环境科学
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催化化学
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DOI
PubMed
高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
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2017
·Vol. 17
·期 12
·8818-8826
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IF 1.483
Liu Jingwei,Huo Minfeng,Zhu Yan
Mn–Na2WO4/SiO2 synthesized by Urea-assisted hydrothermal-Impregnation route has more and stronger surface basic sites, and more surface lattice oxygen, leading to higher methane conversion with higher selectivity toward ethane and ethylene in oxidative
coupling of methane reaction, compared to Mn–Na2WO4/SiO2 produced by Co-precipitation-Impregnation (CPI) and Sequential Impregnation (SI) methods.
研究领域:
催化化学
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材料科学
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产品关联
DOI
高影响因子
ENERGY & FUELS
·
2024
·
IF 5.2
Yanbin Zhang,Xifei Yin,Chenghu Zhang,Ying Li,Yinghui Sun,Jie Bai
Dry reforming of methane (DRM) provides an effective method for converting the two main greenhouse gases to hydrogen and carbon monoxide. In this work, Co-CeO2 and CoM-CeO2 (M = Ru, Pd, Pt) catalysts prepared by electrospinning technology were used for DRM. Due to the excellent catalytic performance of Pt itself, the CoPt-CeO2 catalyst had the highest DRM catalytic performance at 850 °C, with a methane (CH4) conversion of 94.12%, and remained stable in 24 h stability testing with almost no carbon deposition. The surface properties of the samples were characterized by Brunauer–Emmett–Teller (BET), temperature programmed reduction with H2 (H2-TPR), temperatureprogrammed desorption of CO2 (CO2-TPD), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results indicated that part of the reason for the excellent catalytic performance exhibited by adding noble metals to the catalyst is closely related to the high dispersion of active metals. More importantly, the addition of noble metals significantly increased the medium and strong alkaline sites of the catalysts. The abundant oxygen vacancies in CeO2 itself and the increased alkaline sites of noble metals were conducive to the CO2 adsorption and dissociation and the oxidation of deposited carbon. Moreover, the addition of noble metals promoted the interaction between the active metal and support. The results of this study provide a reference for the design of high-performance Co-based DRM catalysts.
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
SEPARATION AND PURIFICATION TECHNOLOGY
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2022
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IF 9.136
Fu Yang,Wenhao Li,Xiu Zhong,Wenlong Tu,Jie Cheng,Lei Chen,Jun Lu,Aihua Yuan,Jianming Pan
The adsorption separation of volatile organic compounds affords an efficient potential solution to address VOC emission. In this work, we reported alkaline sites-modified biomass-carbon adsorbents through in situ implanting MgO for reinforcing the adsorption abatement of polar VOCs. We revealed that the dispersed MgO alkaline sites in situ formed over the activated carbon during the KOH activation process by placing the magnesium acetate and KOH into grapefruit peel-based biochar together, which avoids the repeated postmodification. By tuning the mass proportion of Mg precursor and KOH activator, the optimized loading of magnesium oxide in AC was explored and compared with the MgO post-modified AC using a two-step procedure. The physicochemical properties of MgO-modified AC were characterized by various techniques. Impressively, MgO occupied a higher surface formation ratio (82.6%) in whole Mg species of the in-situ synthesized 10MgO/C compared to that (51.4%) in postimpregnated 10MgO/C-P. The adsorption properties of polar acetic acid and nonpolar benzene over the above comparative adsorbents were systematically studied by the gas-static adsorption method. The results revealed that the optimal sample of 10MgO/C afforded excellent structural properties (S BET = 2646 m 2 g −1 , V total = 1.59 cm 3 g −1 ) and a large adsorption capacity of polar acetic acid reaching 16.64 mmol g −1 at 30 °C. More importantly, compared to unmodified and nitrogen-doped AC, 10MgO/C showed improved acetic acid adsorption capacity, reversible desorption behavior, and lower adsorption heat. The calculation of Ideal Adsorption Solution Theory (IAST) for selective adsorption separation of the CH 3 COOH/C 6 H 6 binary mixture(50/50) over 10MgO/C showed the highest selectivity (3.42). This work offers new insight into the in-situ modification of AC and polar VOCs selective adsorption separation.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Rui Cao,Xueqian Wang,Langlang Wang,Fangxian Cao,Xiang Li,Lu Wang,Jinghao Xiang,Ping Ning
The introduction of surface basic sites to COS hydrolysis catalysts can improve H 2 O activation and COS adsorption, leading to enhanced catalytic performance. However, maximizing the concentration of basic sites remains a challenge due to the limited exposed surface area of these catalysts. Herein, a La/Al 2 O 3 catalyst with abundant alkaline sites to catalyze the hydrolysis of COS was prepared by a simple ammonia-assisted hydrothermal method. This synthesized La/Al 2 O 3 catalyst exhibits a thin rod-like structure formed by the random accumulation of nanoparticles. Lanthanum, one of the most abundant rare earth metals, is an ideal doping aid to further promote the COS-catalyzed hydrolysis performance of Al 2 O 3 . Characterization studies show that the proper lanthanum loading effectively enhances the formation of basic sites, leading to improved lattice oxygen reactivity and –OH adsorption capacity. As a result, the prepared La-loaded Al 2 O 3 nanorod sample with abundant basic sites exhibits nearly 100 % COS conversion and total H 2 S yield at 160 °C. In addition, the reaction pathways and deactivation mechanisms for selective catalytic hydrolysis of COS on the La-doped Al 2 O 3 catalyst were revealed by using in situ DRIFTS to evaluate COS adsorption and hydrolysis. Density functional theory calculations showed that La loading enhances the electron transfer between the La and Al atoms, improves the formation of basic sites, and enhances the adsorption of –OH. This study provides new insights into the design of efficient alumina-based catalysts for the catalytic hydrolysis of COS.
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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DOI
高影响因子
ACS Omega
·
2020
·
IF 2.87
Zheng Shen,Yishan Gao,Ling Kong,Minyan Gu,Meng Xia,Wenjie Dong,Wei Zhang,Xuefei Zhou,Yalei Zhang
Amine-modified Sn-β was synthesized to improve the yield of lactic acid produced from Scenedesmus. After studying the growth of Scenedesmus, we selected Scenedesmus with the highest sugar content of 46.7% after 8 days of culture as the reaction substrate. The results showed that the yield of lactic acid from Scenedesmus was greatly increased after being catalyzed by 3-aminopropyltrimethoxysilane (APTMS)-modified Sn-β. After the pretreatment of Scenedesmus in an ice bath ultrasound, under the optimal reaction conditions (190 °C and 5 h), the yield of lactic acid reached the highest (37%). The acid–base characterization results of the catalyst confirmed that there are both Lewis acidic sites and medium-strength basic sites in the catalyst. Both of these sites can promote the hydrolysis of Scenedesmus, while the Lewis acidic sites can promote the production of lactic acid and the basic sites can effectively inhibit the production of the byproduct 5-hydroxymethylfurfural (HMF). This study proved that this amination catalyst is a useful strategy to increase the yield of lactic acid.
研究领域:
生物化学
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催化化学
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环境科学
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DOI
PubMed
高影响因子
RSC Advances
·
2021
·Vol. 11
·期 25
·15477-15485
·
IF 3.361
Fengjiao Li,Liguo Wang,Shuang Xu,Shuting Liang,Ningning Zhang
Developing cost-effective, high-efficiency and heterogeneous catalysts is of prime importance for the green synthesis of diethyl carbonate (DEC) from ethyl carbamate (EC) and ethanol. Herein, a series of MgO/γ-Al2O3 catalysts were readily fabricated by an impregnation method for DEC synthesis from EC and ethanol. The activities of the as-prepared MgO/γ-Al2O3 catalysts as well as the individual MgO or γ-Al2O3 were first tested in the batch reactor. Among the investigated samples, the MgO/γ-Al2O3 with a MgO loading of 10 wt% (denoted as 10% MgO/γ-Al2O3) exhibited the largest amount of stronger basic sites, and the highest activities with EC conversion of 41.8% and DEC yield of 30.4%, respectively. Furthermore, the DEC yield was greatly boosted to 52.1% with a high DEC selectivity of 93.8% over the 10% MgO/γ-Al2O3 catalyst under the optimized reaction conditions in the fixed bed reactor, outperforming most of the reported catalysts.
研究领域:
催化化学
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绿色化学
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产品关联
DOI
PubMed
高影响因子
Nanomaterials
·
2018
·Vol. 8
·期 5
·275
·
IF 3.504
Jingting Lu,Chengli Jiao,Zeeshan Majeed,Heqing Jiang
Mesoporous carbons (MC) have attracted a tremendous amount of interest due to their efficient molecular transport properties. However, the limited number of active sites and low microporosity generally impede their use for practical applications. Herein, we have fabricated Mg and N co-doped mesoporous carbon (Mg-NMC) with high microporosity via one-pot synthetic route followed by further steam activation. In comparison with the parent N-doped mesoporous carbon, Mg-NMC shows partially ordered mesostructure and improved CO2adsorption capacity attributed to the introduction of basic site after Mg doping. Upon further steam activation, the microporosity is enhanced to 37.3%, while the CO2adsorption capacity is also increased by 70.4% at 273 K and 1.0 bar.Keywords:mesoporous carbon;Mg doping;steam activation;basic site;microporosity;CO2adsorption
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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