APPLIED SURFACE SCIENCE
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2022
·
IF 7.392
Dong Li,Kaixuan Wang,Jiahong Tang,Yizhou Zhao,Hanan Elhaes,Muhammad Tahir,Medhat A. Ibrahim,Yujing Li
Two-dimensional (2D) organic-inorganic hybrid halide perovskites have gained extensive attention in photovoltaics , photodetectors and light-emitting diodes owing to their unique optoelectronic properties and superior stability compared with their three-dimensional (3D) counterparts. However, 2D perovskites have rarely been applied for photochemical conversion applications. Herein, a series of 2D BA 2 MA n-1 Pb n Br 3n+1 perovskite nanosheets have been synthesized through a facile, ligand-free precipitation (LFP) method at room temperature . Using the specific chemical trapping techniques, we show for the first time that the 2D perovskite nanosheets can effectively generate photosensitized singlet oxygen ( 1 O 2 ) via energy transfer from triplet excitons to molecular oxygen in non-polar solvent. Based on this discovery, the as-prepared BA 2 PbBr 4 and BA 2 MAPb 2 Br 7 nanosheets successfully catalyze the ENE reaction and 1,2-addition reaction between olefin and singlet oxygen under visible light . Our study is anticipated to develop and demonstrate new mechanisms for 2D halide perovskite materials in photodynamic therapy and photocatalytic applications.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2016
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IF 5.31
Shuaishuai Ding,Qing Yan,Hong Jiang,Zhaoxiang Zhong,Rizhi Chen,Weihong Xing
By adjusting the addition time of palladium nanoparticles, during the formation of ZIF-8, an efficient and facile method was proposed to control the palladium spatial distribution within ZIF-8 crystals. Characterizations reveal that the addition time can significantly affect the particle size of Pd@ZIF-8 and palladium spatial distribution. As the PVP-stabilized palladium nanoparticles are added at the early stage of the ZIF-8 formation, larger ZIF-8 crystals with completely embedded palladium nanoparticles can be obtained. Introducing the PVP-stabilized palladium nanoparticles later can lead to the formation of smaller ZIF-8 crystals with all the palladium nanoparticles on the outer surfaces of ZIF-8. The catalytic performance of Pd@ZIF-8 strongly depends on the palladium spatial distribution, and the Pd@ZIF-8 with completely embedded palladium nanoparticles can provide excellent product selectivity and better catalytic stability in the hydrogenation of alkenes.
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高影响因子
GREEN CHEMISTRY
·
2023
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IF 9.8
Shihao Su,Guojun Lv,Xuyang Zou,Jiangzhang Wang,Chaoyi Zhou,Yan Chen,Jialing Shen,Yangbin Shen,Zhongmin Liu
In the cyclic alkene epoxidation reactions using molecular oxygen as oxidant, aldehyde is generally added as co-oxidant to assist transition metal catalyst to activate the oxygen molecule, oxidizing cyclic alkene and producing the corresponding epoxide; however, the added aldehyde would be converted into byproduct carboxylic acid. Herein, we report the room-temperature tandem conversion of cyclic alkenes into 1,2-diols through the application of byproduct carboxylic acid as a catalyst for epoxide hydration reaction, realizing effective utilization of the byproduct and saving energy consumption. Four kinds of nanosized MnO2 specimens, including α-, β-, δ-, and γ-MnO2, were hydrothermally synthesized and applied as heterogeneous catalysts for the room-temperature tandem conversion of cyclohexene into 1,2-cyclohexanediol using molecular oxygen as oxidant and isobutyraldehyde as co-oxidant. The characterization results demonstrated that the obtained β-MnO2 sample had the maximum Mn4+/Mn3+ ratio of 1.42 and the minimum Oads/OLatt ratio of 0.34, consistent with its least oxygen vacancies evidenced by EPR measurement. Accordingly, the β-MnO2 sample revealed the quickest alkene epoxidation reaction rate and could achieve a 99.2% cyclohexene conversion within 1 h, and meanwhile, a 73.6% 1,2-cycloheanediol yield could be attained within 24 h. A plausible mechanism for the tandem conversion of cyclohexene into 1,2-cyclohexanediol over the β-MnO2 heterogeneous catalyst was proposed and further verified by quenching experiments and DFT calculations. Furthermore, the synthesized β-MnO2 catalyst sample could be reused more than ten times, and meanwhile, the tandem conversion way could be expanded to most of the cyclic alkene substrates, which demonstrated that the β-MnO2 catalyst was an active and stable heterogeneous catalyst for tandem conversion of cyclic alkenes into 1,2-diols.
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Chemistry-An Asian Journal
·
2021
·Vol. 16
·期 19
·2952-2957
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IF 4.568
Fengwei Zhang,Mengmeng Liu,Qiang Liu,Jingjing Li,Boyang Li,Zhengping Dong
Graphical A facile and in-situ methanol-mediated strategy was proposed to fabricate Pd@ZIF-8 catalyst for efficient and size-selectivity alkenes hydrogenation. In-situ encapsulation of tiny and well-dispersed Pd nanoparticles (Pd NPs) in zeolitic imidazolate frameworks (ZIFs) was firstly achieved using a one-pot and facile methanol-mediated growth approach, in which methanol served as both solvent and a mild reductant. The microstructure, morphology, crystallinity, porosity as well as evolution process of the catalysts were determined by TEM, XRD, N 2 adsorption and UV-vis spectra. Due to the complete encapsulation of such Pd NPs combined with ultrahigh surface area and uniform microporous structure of ZIF-8, the resulting Pd@ZIF-8-60 min nanocomposite exhibited more superior catalytic activity for olefins hydrogenation with TOF of 7436 h −1 and excellent size selectivity than previously reported catalysts. Furthermore, the catalyst displays excellent recyclability for 1-octene hydrogenation and without any loss of the Pd active species.
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PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2020
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IF 4.551
Xinchao Liu,Jing Wang,Yongde Xia,Xinhuan Lu,Qinghua Xia,Dan Zhou
From the considering of simple synthesis step, low cost, and energy saving, one-step synthesis of hierarchical zeolite without involving additional template has obvious advantages compared with post-synthetic modification or one-step templating methods, by which Ti-containing hollownest structure zeolite (Ti-HSZ) has been successfully synthesized. Herein, the origin of Ti-HSZʼs hollownest structure has been investigated by systematical comparison study between the rotating hydrothermal (RH) and static hydrothermal (SH) synthesis routes. It is found that different synthesis routes not only influence the crystallization but also determine the chemical and physical properties of zeolites. Compared with the catalyst prepared by flower-like precursor with larger size obtained by SH route in 12 days, Ti-HSZ catalyst with smaller size formed by RH route in 3.5 days shows higher catalytic activity for the epoxidation of bulky alkenes with H 2 O 2 . On one hand, the rapid and efficient transports of various reaction species in RH environment has accelerated the crystallization rate greatly; on the other hand, the one-step self-assembly of lamellar MWW crystals has happened to facilitate the formation of hollownest structure with hierarchical pores through intergrowth driven by centrifugal force. The different evolution processes of the Si chemical environments during the early stages of crystallization reflected by the percentage of intrinsic defects origin from the different hydrothermal environments. Highly mixed and dispersed reaction species under RH condition accelerate the uniform of gel concentration, and the condensation of smaller clusters with different orientation direction through frequent contacting under dynamic condition is easy to happen to form bigger clusters, which is the basis for the further crystal intergrowth. In contrast, the relatively inhomogeneous gel environments under SH condition has led to the increase of intrinsic defects in the solid phases, and bigger clusters tend to be formed by the condensation of smaller ones with the same orientation direction. This work will be instructive not only for the understanding of zeolites’ crystallization mechanism, but also for the design and synthesis of zeolite materials with unique morphology characteristics.
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高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
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2020
·Vol. 34
·期 8
·e5697
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IF 3.14
Yingpeng Huo,Jiwen Hu,Yuanyuan Tu,Zhenzhu Huang,Shudong Lin,Yangfei Hu,Chao Feng
An imidazolyl Schiff base-containing periodic mesoporous organosilica (PMO) was synthesized via co-condensation reactions between a newly prepared bis (imidazolyl)imine-bridged bis silane and tetraethyl orthosilicate in the presence of cetyltrimethyl ammonium bromide as a soft template. The resultant as-synthesized PMO was then employed as a solid support for platinum catalysts. This complex was fully characterized via various techniques including FTIR, solid-state 13 C NMR, and 29 Si-NMR spectroscopy, as well as N 2 adsorption/desorption analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) methods. In addition, the catalyst was proven to efficiently mediate hydrosilylation reactions between olefins and hydrosilanes, and it can be reused for at least five cycles without significant loss of activity.
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高影响因子
APPLIED SURFACE SCIENCE
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2021
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IF 6.707
Dingxuan Ma,Yaowen Zhang,Huihui Zhao,Kang Liu,Lei Wang
Porous organic frameworks (POFs) catalysts with a combination of the well-developed porosity and highly dispersed of active sites hold promise for boosting catalyst activity and selectivity. Among their many synthetic methods, one-step knitting strategies have gained superiority and potential for development. Here, two copper porphyrin based microporous polymers (SC-Cu and FC-Cu) were directly synthesized through Scholl coupling reaction and Friedel-Crafts alkylation reaction respectively, which possess high surface area and efficient catalytic performance for styrene oxidation. Moreover, the hierarchical pores of SC-Cu gave it a unique catalytic performance with various olefins with excellent conversion rate. The insight achieved by this systematic analysis will contribute to the rational design of other POFs catalysts and widening extent of applications.
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高影响因子
Molecular Catalysis
·
2019
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IF 2.938
Zhijie Wang,Anxiang Guan,Mayfair C. Kung,Anyang Peng,Harold H. Kung,Ximeng Lv,Gengfeng Zheng,Linping Qian
Aerobic oxidation of α-C H bond of organic compounds to valuable chemicals is widely investigated in both fundamental research and industry. Due to the good stability of molecular oxygen, severe reaction conditions are generally required. Herein, by in situ synthesis we used molecular oxygen to induce cobalt nanoclusters with the sensitive catalysis in mild selective oxidation. The cobalt containing clusters with an average diameter around 0.9 nm are in situ prepared in the presence of cis -cyclooctene epoxidation and cyclooctene dimer oxide is formed at the interface to stabilize Co clusters with electron donation as an oil-soluble surfactant. The soluble clusters exhibit high activity in selective oxidation of α-C H bond of ethylbenzene into acetophenone and turnover number (TON) reaches about 7 × 10 4 during 50 h’ reaction at 373 K, which is around 960 times more active than the one using CoCl 2 salt as the catalyst, resulting from efficient mass transportation, π bond interaction and oxygen gas activation. Extended work based on this understanding demonstrates that cobalt nanoclusters also effectively catalyze aerobic oxidation of cyclohexene.
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高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2019
·Vol. 35
·期 2
·251-255
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IF 1.071
He Qian,Zhang Ying,Xiao Huajian,He Xiaohui,Zhou Xiantai,Ji Hongbing
A facile co-precipitation method was developed to prepare the novel metalloporphyrins-Ba 2+ composites with ca. 3 μm diameter and olive-like morphology. Olefins epoxidation reactions were employed to investigate their catalytic performance. Compared with the free metalloporphyrins, the composites exhibited not only the improved stability and recyclability, but also the enhanced catalytic activity. Such catalytic behaviors could be related to the unique structure of the composites, e.g., the strong interaction between R-SO 3 - and Ba 2+ ions and the uniform distribution of metalloporphyrins on the catalyst surface, respectively. Furthermore, the composites showed good compatibility with a wide range of substrates. The well-designed composites are expected to be efficient catalysts, alternative to many sophisticated-synthesized metalloporphrins-based materials, in the industrially important reactions.
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高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2019
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IF 2.781
Yun Yang,Tianjun Zhang,Dan Zhou,Xinchao Liu,Shuijin Yang,Xinhuan Lu,Qinghua Xia
Recently, a Ti-containing hollownest-structured zeolite (Ti-HSZ) material with the shell constructed by randomly intergrown MWW (framework type code) flaky crystals has been synthesized through one-step rotating hydrothermal method within 3.5 days, which shows predominant catalytic property for the epoxidation of alkenes . Herein, it is firstly reported that the crystallization efficiency of Ti-HSZ material can be notably increased by applying seeds-assisted synthesis method. Thus-crystallized materials have been characterized by XRD , UV–vis, XPS , SEM , TEM, FT-IR, and N 2 adsorption-desorption. Moreover, the key controlling factors are revealed to include the addition percentage of seed crystals, rotating rate and filling degree of autoclave. When 2 wt% or 3 wt% seed crystals are added into the reaction gel, the crystallization time of Ti-HSZ can be sharply reduced to 2.5 days or even 2.0 days, respectively. Particularly, thus-synthesized Ti-HSZ-SM material still maintains hollownest morphology characteristic and excellent catalytic activity and catalytic stability. About 95% allyl chloride can be converted into corresponding epoxide when using H 2 O 2 as oxidant, and about 85% cyclopentene and 87% cyclooctene can be converted into corresponding epoxides when using TBHP as oxidant, with the selectivity for epoxides of nearly 100%.
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高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2014
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IF 2.235
Qingshan Zhao,Chan Bai,Wenfeng Zhang,Yang Li,Guoliang Zhang,Fengbao Zhang,Xiaobin Fan
Immobilization of metal complexes on solid supports is an efficient approach to remedy the drawbacks of homogeneous catalysis. In this study, an in situ strategy of synthesis and immobilization of a copper (salen) complex onto graphene oxide (GO) support has been developed. To provide the salen ligands, GO was covalently modified with an aminosilane, followed by condensation with salicylaldehyde. The copper (salen) complex was subsequently synthesized and simultaneously immobilized onto the GO surface with a designed tetrahedral chelate structure. The immobilized copper (salen) complex [Cu(salen)–f–GO] kept the two-dimensional sheetlike character of GO and was demonstrated to be highly effective for the epoxidation of olefins. It could be readily reused for successive twelve times without discernible activity and selectivity deterioration, which displays potential for practical applications.
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高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2014
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IF 2.235
Lu Lin,Tong Zhang,Xiongfu Zhang,Haiou Liu,King Lun Yeung,Jieshan Qiu
In this work, we fabricated a new type of Pd/SiO2@ZIF-8 core–shell catalyst composed of a Pd/SiO2 microsphere as the core and a ZIF-8 membrane as the shell. The preparation procedure involves first loading Pd nanoparticles onto nonporous SiO2 microspheres to obtain the Pd/SiO2 core and then coating a perfect layer of ZIF-8 shell on the core by electrostatic induction to form a Pd/SiO2@ZIF-8 core–shell structure. It is crucial that the modification of the Pd/SiO2 core with polyelectrolyte was employed to improve the charge distribution of the core surface and preferably adsorb Zn2+ cations in the synthesis solution so as to assist the formation of a continuous ZIF-8 shell. The compactness and thickness of the shell were optimized by increasing the number of cycles of ZIF-8 growth. The hydrogenations of alkenes with different molecular sizes showed that the Pd/SiO2@ZIF-8 catalysts can provide excellent product selectivity and antipoisoning and antileaching properties for the hydrogenations of alkenes.
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高影响因子
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