APPLIED CATALYSIS A-GENERAL
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2013
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IF 3.41
Jin Zhao,Jun Xie,Chak-Tong Au,Shuang-Feng Yin
We report a new strategy for one-pot synthesis of potassium-loaded MgAl oxides using KOH to adjust the pH value of the reaction system. The as-prepared solid superbases were studied by N 2 physisorption method, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, and Fourier transform infrared. The superbasic sites were characterized by the use of Hammett indicators and CO 2 temperature-programmed desorption. We found that with a base strength ( H – ) above 26.5, the potassium-loaded MgAl oxides showed high catalytic activity for Knoevenagel condensation at room temperature. Furthermore, the higher the superbasicity and/or the more the amount of superbasic sites, the better is the catalytic activity. The findings open up a new route for the synthesis of new functional superbases using composite oxides as supports.
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
Polymers
·
2023
·Vol. 15
·期 2
·279
·
IF 5
Shiping Zhou,Faqin Dong,Yilin Qin
In this study, we analyzed the removal efficiency of uranium(U(VI)) in wastewater at relatively low concentrations using strong alkaline ion exchange fiber (SAIEF). Static tests showed that the strong alkali fibers can purify U(VI) containing wastewater in a concentration range of 20–100 mg L−1with an optimal pH of 10.5 and contact time of 15–30 min. Adsorption and desorption cycling tests indicated that, adsorbed uranium is easily desorbed by 0.1 mol L−1HCl, and the fiber still maintained the original adsorption efficiency after eight cycles. According to dynamic penetration test results, the SAIEF saturation adsorption capacity was 423.9 mg g−1, and the effluent concentration of uranium through two series columns was less than 0.05 mg L−1, reaching the national standard for non-receiving water (GB23727-2009) SEM-EDS and FTIR analysis revealed that the functional group of SAIEF is CH2N+(CH3)3Cl−. Addotionally, the major forms of fiber exchange adsorption are (UO2)2CO3(OH)3−, UO2(CO)34−and UO2(OH)3−. The results indicate that the SAIEF is an excellent material for uranium removal.Keywords:strong alkaline ion exchange fiber;uranium(VI);deep purification
研究领域:
环境科学
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材料科学
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DOI
PubMed
高影响因子
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
LANGMUIR
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2023
·
IF 3.9
Nan Wang,Zhao-Jian Li,Hong Gao,Ru Li,Xiao-Feng Xu,Tong Li,Yun-Ze Long,Hong-Di Zhang
Traditional SrTiO3 (STO) materials have high brittleness and poor deformation resistance. In this work, macroscopically flexible iron-doped SrTiO3 (SFTO) nanofibrous membranes were prepared by electrospinning and calcination, which can be easily isolated and can maintain integrity to recycle as photocatalysts. Moreover, the SFTO nanofibrous membranes showed enhanced photocatalytic performance under strong acids (pH = 2) and strong alkalis (pH = 12). The SFTO nanofibrous membranes increased the catalytic rate of Congo red (CR) dye by about 10 times in visible light. The mechanism of photocatalytic activity enhancement was discussed by the combined effects of hydroxyl radicals and superoxide radicals. The successful preparation of SFTO nanofibrous membranes has offered a simple and economical approach to photocatalysis as well as environmental remediation.
研究领域:
材料科学
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环境科学
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DOI
PubMed
高影响因子
Molecular Catalysis
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2020
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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
Polymer Chemistry
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2017
·Vol. 8
·期 9
·1579-1588
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IF 5.375
Zhiquan Li,Weizhen Shen,Xiaoya Liu,Ren Liu
Simultaneous thiol-based hybrid photopolymerization is an efficient and versatile tool to prepare interpenetrating polymeric networks. A highly active photoinitiator is essential for an efficient simultaneous hybrid reaction. In this paper, several unimolecular photoinitiators, which contain thioxanthone derivatives as chromophores as well as free radical generators, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as a latent alkaline species, were straightforwardly prepared in two steps. The photolysis study indicated that under 405 nm LED light irradiation, the photoinitiators can produce free radicals and a strong base simultaneously via a photodecarboxylation mechanism. The generated active species are highly efficient in catalyzing thiol–yne–epoxy hybrid polymerization without post-exposure baking and the properties of the hybrid network can be tailored by adjusting the compositional ratios of the formulations. The photocured materials using unimolecular photoinitiators exhibit superior thermal and mechanical properties compared to those prepared using a bimolecular initiation system from the literature. The presented strategy to realize simultaneous thiol–yne–epoxy hybrid photopolymerization shows potential for the fabrication of optical devices with enhanced refractive index and improved mechanical properties.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
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2023
·Vol. 24
·期 18
·14313
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IF 5.6
Jiaqi Shi,Lei Wang,Shang Gao,Jianbo Huang,Hao Yang,Hao Lu,Shaohua Cao
Alkali-activated persulfate (PS) is widely used in situ in chemical oxidation processes; however, studies on the innovation of the alkali activation process are very limited. Two supported solid superbases, namely KNO3/γ-Al2O3(KAl) and KNO3/SBA-15/MgO (KSM), respectively, were prepared and used to activate persulfate to degrade DCF in this work. The results showed that the superbases elevated the solution pH once added and thus could catalyze persulfate to degrade diclofenac efficiently above pH 10.5. The catalytic efficiency of KAl was close to that of sodium hydroxide, and that of KSM was the highest. The mechanism might be that, in addition to raising the solution pH, some potassium existed as K2O2, which had a strong oxidizing effect and was conducive to DCF removal. Hydroxyl, sulfate and superoxide radicals were all found in the reaction system, among which hydroxyl might play the most important role. The material composition ratio, common anion and humic acid all had some influences on the catalytic efficiency. A total of five intermediates were found in the KSM/PS oxidation system, and six oxidation pathways, which were hydroxylation, dehydrogen, dechlorination, dehydration, decarboxylation, and C-N bond breakage, might be involved in the reaction process. Several highly toxic oxidation products that should be paid attention to were also proposed.Keywords:base-activated persulfate;catalytic mechanism;diclofenac;solid superbase
研究领域:
环境科学
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化学工程
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DOI
PubMed
高影响因子
RSC Advances
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2016
·Vol. 6
·期 94
·91968-91980
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IF 3.289
Fu Yang,Bangbang Wang,Shijian Zhou,Xiaoning Yang,Yan Kong
Catalytic performance of heterogeneous catalysis is strongly dependent on the dispersity of catalytic active sites, and especially a high exposure of the unit active phase is promising for the overall catalytic process. In this study, a novel strategy was developed to fabricate an unprecedented CaO-based mesoporous solid strong base catalyst. Relying on the physicochemical assembly of Ca2+ in the interface between a micelle and siliceous wall, thin-layer-like calcium oxide species were formed in situ and dispersed in the mesochannels of silica. Wherein, the gradual coverage of CaO on the mesoporous wall was controlled by adjusting the amounts of Ca2+ on alkylamine micelles. Interestingly, a novel sponge-like microscale structure of silica was discovered in the CaO-based mesoporous-composites for the first time, which completely differs from the reported mesoporous silica. More importantly, the introducing of a CaO solid base on the pore wall is nearly non-destructive for the textural properties of the mesoporous matrix. The direct template-induced mesoporous solid strong base not only received extremely dispersed and unexpected enhanced strong basic sites (CO2-desorption temperature ≥718 °C), but also avoided repeated thermal processes for the degradation of the basic resource, and saved energy and time. This heterogeneous alkaline catalyst shows excellent catalytic activity for the synthesis of dimethyl carbonate under a milder reaction condition (30 °C, 25 min) and holds stability and reusability beyond comparison with the conventional catalysts. The dispersed and enhanced strong basic sites, combined with excellent mesoporous properties, are demonstrated to be responsible for such a high catalytic performance.
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 Processing and Synthesis
·
2021
·Vol. 10
·期 1
·874-881
·
IF 2.83
Xin Zhou,Ge Gao,Guangxiang He,Xiaoyan Guo,Haibo Jin,Lei Ma
The side-chain alkylation of cumene and ethylene over a solid superbase catalyst K/KOH/ γ -Al 2 O 3 is investigated. The effects of the reaction temperature, pressure, and time on the conversion of cumene and selectivity of tert -amylbenzene (TAB) are discussed. The experimental results show that the conversion of cumene to tert -pentylbenzene increases with the increase in reaction temperature and ethylene pressure. The catalytic reaction has certain operational flexibility in terms of the reaction temperature, pressure, and time. In addition, the catalytic reaction can achieve directional conversion. The optimum operating conditions are obtained using a single factor test. The conversion of cumene is 99.8% and the selectivity toward TAB is 97.9% under catalyst concentration of 4 wt%, reaction temperature of 55°C, reaction pressure of 0.45 MPa, and reaction time of 30 min. The deactivation of catalyst is mainly caused by oxygen and water in the raw material.
研究领域:
催化化学
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有机合成
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DOI
高影响因子
Catalysts
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2024
·Vol. 14
·期 5
·324
·
IF 3.8
Jing Wang,Lingling Feng,Zikang Zhao,Yan Wang,Ying Zhang,Shan Song,Shengwei Sun,Junshuang Zhou,Faming Gao
Given the energy crisis and escalating environmental pollution, the imperative for developing clean new energy is evident. Hydrogen has garnered significant attention owing to its clean properties, high energy density, and ease of storage and transportation. This study synthesized four types of catalysts—FeS(DI/MB), FeS(ET/MB), Fe(DI/MB), and Fe(ET/MB)—using two distinct solution systems: DI/MB and ET/MB. The FeS(DI/MB) catalyst, synthesized using the layered solution system (DI/MB), demonstrates a uniformly distributed and dense nanosheet structure, exhibiting excellent resistance to strong bases and superior catalytic properties. The FeS(DI/MB) electrode showed OER overpotentials of 460 mV and 318 mV in 1 M and 6 M, respectively, at current densities of up to 500 mA cm−2. Under industrial electrolysis test conditions, the FeS(DI/MB) electrode required only 262 mV to achieve a current density of 500 mA cm−2, operating in a high-temperature, strong alkaline environment of 6 M at 60 °C. Furthermore, the FeS(DI/MB) electrode exhibited excellent OER catalytic activity and stability, as evidenced by a 60 h stability test These findings provide valuable insights into the preparation of iron nickel sulfide-based catalysts, and further in-depth and comprehensive exploration is anticipated to yield the excellent catalytic performance of these catalysts in the realm of electrolytic water hydrogen production.
研究领域:
化学
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能源科学
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材料科学
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DOI
高影响因子
ACS Applied Materials & Interfaces
·
2018
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IF 8.097
Guozhi Zhu,Song Shi,Meng Liu,Li Zhao,Min Wang,Xi Zheng,Jin Gao,Jie Xu
Porous solid bases are increasingly attractive for applications in green chemistry and heterogeneous catalysis under relatively mild conditions. Here, covalent triazine frameworks (CTFs) were first applied as a support for the porous solid strong bases through a redox process between the base precursor KNO3 and CTFs, leading to a relatively low calcination temperature (400 °C). As a result, porous organic frameworks possessing ordered microstructures as well as strong basic sites were successfully synthesized. The materials were characterized by X-ray diffraction, Fourier transform infrared, high-resolution transmission electron microscopy, temperature programmed desorption of CO2, and so forth. The obtained solid bases displayed remarkable catalytic activity in the aerobic oxidation of methylene compounds, and the yield of fluorenones could reach 93.6% at 120 °C, which was nearly 3 times higher than that of the control catalyst. The current research may present a new idea for the construction of porous organic polymers with strong basicity.
研究领域:
材料化学
·
绿色化学
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产品关联
DOI
PubMed
高影响因子
FUEL PROCESSING TECHNOLOGY
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2017
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IF 3.752
Xiang-Xue Liu,Zhi-Min Zong,Wei-Tu Li,Xiang Li,Zhan-Ku Li,Sheng-Kang Wang,Xian-Yong Wei
A novel and highly active magnetic solid superbase (MSSB) with extraordinary recovery and recycling properties was prepared by impregnating Mg 2 Si onto mesoporous silica coated magnetite via one-pot preparation and successfully applied in the catalytic hydroconversion (CHC) of sawdust at 220 °C. Detailed molecular compositions of the soluble portions from non-catalytic hydroconversion (SP NCHC ) and CHC (SP CHC ) were characterized with a Fourier transform infrared spectrometer and gas chromatograph/mass spectrometer (GC/MS). As a result, the yield of SP CHC is significantly higher than that of SP NCHC and most of the GC/MS-detectable compounds in SP CHC are guaiacols , while SP NCHC is rich in guaiacols and esters, indicating that MSSB effectively catalyzed the cleavage of C O bridged bonds in sawdust. The mechanism for catalytically hydrocracking C O bridged bonds over MSSB is proposed using benzyloxybenzene and oxybis(methylene)dibenzene as model compounds. MSSB can be easily separated by using an external magnetic field and the recovered MSSB proved to be still highly active for catalyzing the hydrocracking of C O bridged bonds in sawdust.
研究领域:
化学工程
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生物质转化
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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）