- Tunable Synthesis of Ultrathin BiOCl 2D Nanosheets for Efficient Photocatalytic Degradation of Carbamazepine upon Visible-Light Irradiation
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A series of ultrathin BiOCl 2D nanosheet photocatalysts were prepared by the TBAOH-assisted hydrolysis method in water. The effects of tetrabutylammonium hydroxide (TBAOH) dosages, chlorine source, preparation pH value, ultrasonic treatment, and magnetic stirring on the photocatalytic degradation dynamics of carbamazepine were examined under visible-light irradiation to optimize the preparation parameters. It was found that ultrathin BiOCl prepared with TBAOH dosages of 1 mmol and chlorine source of NaCl in the pH of 2 upon magnetic stirring of 6 h displayed the highest photocatalytic degradation rate constant (0.0038 min-1) of carbamazepine, which is 7.6 times higher than that with the ordinary BiOCl (without TBAOH). To clarify the mechanism on the outstanding photocatalytic activity of ultrathin BiOCl, the elemental composition/state, micromorphology, and separation efficiency of photogenerated electron-hole pairs were investigated by X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and photoluminescence (PL). Results showed that the presence of oxygen vacancy, ultrathin nanosheet structure, and improved separation efficiency of photogenerated electron-hole pairs contributed to the excellent photocatalytic degradation activity of ultrathin BiOCl. The obtained result provides a novel method to fabricate ultrathin BiOCl with excellent photocatalytic degradation activity of carbamazepine under visible-light irradiation.
- Gao, Xiaoya,Jin, Pengfei,Kuang, Yongmei,Sarkar, Tapan,Xu, Shuo,Xu, Wenfeng
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- Mechanism of Bi?Ni Phase Formation in a Microwave-Assisted Polyol Process
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Typically, intermetallic phases are obtained in solid-state reactions or crystallization from melts, which are highly energy and time consuming. The polyol process takes advantage of low temperatures and short reaction times using easily obtainable starting materials. The formation mechanism of these intermetallic particles has received little attention so far, even though a deeper understanding should allow for better synthesis planning. In this study, we therefore investigated the formation of BiNi particles in ethylene glycol in a microwave-assisted polyol process mechanistically. The coordination behavior in solution was analyzed using HPLC-MS and UV-Vis. Tracking the reaction with PXRD measurements, FT-IR spectroscopy and HR-TEM revealed a successive reduction of Bi3+ and Ni2+, leading to novel spherical core-shell structure in a first reaction step. Bismuth particles are encased in a matrix of nickel nanoparticles of 2 nm to 6 nm in diameter and oxidation products of ethylene glycol. Step-wise diffusion of nickel into the bismuth particle intermediately results in the bismuth-rich compound Bi3Ni, which consecutively transforms into the BiNi phase as the reaction progresses. The impacts of the anion type, temperature and pH value were also investigated.
- Damm, Christine,Doert, Thomas,Ruck, Michael,Smuda, Matthias
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- The characteristics and photocatalytic activities of BiOCl as highly efficient photocatalyst
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BiOCl was synthesized by hydrolysis method. In order to evaluate their photocatalytic activity, this compound was tested on the degradation reaction of methylene green in aqueous solution. The characterization of the compound included: X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopic image (TEM). MG could be efficiently degraded in aqueous suspension of BiOCl under visible light irradiation. Complete removal of aqueous methylene green (MG) was realized after visible light irradiation for 120 min with existing BiOCl as a catalyst. The decrease of the chemical oxygen demand (COD), the formation of inorganic products (SO42- and NO3-) confirmed complete mineralization of aqueous MG during the photocatalytic process.
- Pare, Brijesh,Sarwan, Bhawna,Jonnalagadda
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- A novel enhanced visible-light-driven photocatalyst via hybridization of nanosized BiOCl and graphitic C3N4
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Nanosized C3N4/BiOCl composites were synthesized via a facile method in the presence of arabic gum. Arabic gum acts as the structure-directing agent and helps the formation of BiOCl nanoparticles. A significant enhanced photodegradation is observed and a possible mechanism is proposed by combining photosensitization and photocatalysis. This journal is
- Lei, Liwen,Jin, Huihui,Zhang, Qi,Xu, Jun,Gao, Da,Fu, Zhengyi
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- In-situ precipitation synthesis of novel BiOCl/Ag2CO3 hybrids with highly efficient visible-light-driven photocatalytic activity
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Novel BiOCl/Ag2CO3 hybrid photocatalysts were facilely fabricated in situ precipitation method. The as-prepared samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (FE-SEM), X-ray diffra
- Fang, Shanshan,Ding, Chaoying,Liang, Qian,Li, Zhongyu,Xu, Song,Peng, Yanyan,Lu, Dayong
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- Photocatalytic degradation of trichloroethylene over BiOCl under UV irradiation
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In this study, BiOCl samples were synthesized under different pH values and characterized by XRD, SEM, UV-vis DRS, BET, photoelectrochemical measurement and PL. The photocatalytic performances of the as-prepared samples were evaluated through the decomposition of trichloroethylene (TCE) under UV irradiation. The influences of several parameters such as solution pH and common inorganic anions on TCE removal were investigated. Results indicated that BiOCl-0.6 exhibited better photocatalytic performance than BiOCl-6.0 because of its higher migration ability of photo-induced carrier. The photocatalytic degradation of TCE over BiOCl-0.6 followed pseudo first-order kinetics and appeared to be more efficient in acidic solution than in alkaline. TCE was almost completely dechlorinated in 120?minutes. The inhibiting effect of naturally occurring anions was in the order of HCO3 - >SO4 2- >NO3 -, while Cl- exhibited a dual effect. Moreover, BiOCl-0.6 exhibited superior reusability after three cycles of repetition tests.
- Liu, Wei,Yang, Qi,Wang, Zhen,Lv, Xiaofan,Yang, Zhilin
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- One-dimensional BiPO4 nanorods and two-dimensional BiOCl lamellae: Fast low-temperature sonochemical synthesis, characterization, and growth mechanism
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Regular BiPO4 nanorods, for the first time, and BiOCl lamellae have been successfully synthesized via a facile sonochemical method in a surfactant/ligand-free system under ambient air. The as-prepared products are characterized by XRD, TEM, SAED, FE-SEM, HRTEM, and Raman spectroscopy. The effects of pH and ultrasound irradiation on the phase and morphology of the products are studied and the sonochemical formation mechanisms of 1D and 2D structures are discussed. TEM data from samples made after different reaction times suggest an ultrasound-induced nucleation and an oriented-attachment growth mechanism.
- Geng, Jun,Hou, Wen-Hua,Lv, Yi-Nong,Zhu, Jun-Jie,Chen, Hong-Yuan
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- Microwave-assisted ionothermal synthesis of hierarchical microcube-like BiOBr with enhanced photocatalytic activity
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Bismuth oxybromide (BiOBr) with a hierarchical microcube morphology was successfully synthesized via microwave-assisted ionothermal self-assembly method. The as-obtained BiOBr was composed of regular multi-layered nanosheets, which were formed by selective adsorption of ionic liquids on the Br-terminated surface, followed by the formation of hydrogen bond-co-π-π stacking. The synthesized BiOBr exhibited high activity, excellent stability, and superior mineralization ability in the photocatalytic degradation of organic dyes under visible light owing to its enhanced light absorbance and narrow bandgap. Furthermore, photo-generated electrons were determined to be the main active species by comparison with different trapping agents used in the photocatalytic reactions.
- Miao, Yingchun,Lian, Zichao,Huo, Yuning,Li, Hexing
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- Inlay of Bi2O2CO3 nanoparticles onto Bi2WO6 nanosheets to build heterostructured photocatalysts
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Surface-dispersive-type Bi2O2CO3/Bi 2WO6 heterostructured nanosheets were successfully prepared via anion exchange in a hydrothermal process with the graphitic carbon nitride (g-C3N4) as a precursor of CO3 2-. The Bi2O2CO3 nanoparticles (with diameters about 5 nm) were highly homogeneously dispersed and inlaid in the single-crystalline Bi2WO6 nanosheets. The composites with intimate interfacial contacts between Bi2O2CO3 and Bi2WO6 exhibited superior visible light photocatalytic activity towards the degradation of rhodamine B (RhB). The composite nanosheets containing 7.86 wt% Bi2O2CO3 showed the best performance and the degradation rate of RhB was 6 times faster than that with the bare Bi2WO6. The dramatic enhancement of the photocatalytic activity of the Bi2O2CO3/Bi 2WO6 photocatalysts can be attributed to the hetero-interfaces between Bi2O2CO3 and Bi 2WO6, their intrinsically layered structure, two-dimensional morphology and the effective separation of the photoinduced carriers at the interfaces and in the semiconductors. This method can be used to design and prepare other Aurivillius heterostructured semiconductors for efficient light harvesting and energy conversion applications.
- Xu, Yang-Sen,Zhang, Ze-Jun,Zhang, Wei-De
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- Transformations of ruddlesden-popper oxides to new layered perovskite oxides by metathesis reactions
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We report transformations of the Ruddlesden-Popper (R-P) oxide, K2La2Ti3O10, to layered perovskite oxides, (Bi2O2)La2Ti3O10, MLa2Ti3O10 (M = Pb, Ba, Sr), and (VO)La2Ti3O10, by a novel metathesis reaction with BiOCl, MCl2, and VOSO4·3H2O, respectively. The formation of (VO)La2Ti3O10, which occurs in aqueous medium around 100°C, suggests that the reaction is most likely topotactic, where the structural integrity of the perovskite sheet is preserved. We believe that the method described here provides a new general route for the synthesis/assembly of layered perovskite materials containing MX/M2X2 sheets, as indeed shown by the independent report of (CuX)LaNb2O7 synthesis by a similar reaction.
- Gopalakrishnan,Sivakumar,Ramesha,Thangadurai,Subbanna
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- Template-free synthesis and enhanced photocatalytic performance of uniform BiOCl flower-like microspheres
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Preparation of uniform BiOCl flower-like microspheres was facilely accomplished through a simple protocol involving regulation of pH value in aqueous with sodium hydroxide in the presence of n-propanol. The as-prepared samples were characterized by a collection of techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), and nitrogen adsorption-desorption isotherms. Based upon the SEM analyses, uniform microspheres could be formed with coexistence of some fragments of BiOCl nanosheets without n-propanol. The addition of appropriate amount of n-propanol was beneficial to provide BiOCl samples containing only flower-like microspheres, which were further subjected to the photocatalytic measurements towards Rhodamine B in aqueous under visible light irradiation and exhibited the best catalytic performance among all samples tested. In addition, the photocatalytic process was confirmed to undergo through a photosensitization pathway, in which superoxide radicals (?·O-2-) played critical roles.
- Chang, Fei,Xie, Yunchao,Chen, Juan,Luo, Jieru,Li, Chenlu,Hu, Xuefeng,Xu, Bin
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- Effect of drying temperatures on structural performance and photocatalytic activity of BiOCl synthesized by a soft chemical method
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A group of BiOCl photocatalysts with different drying temperatures were prepared by a soft chemical method. The effects of drying temperatures on the crystalline phase, morphology, surface area and optical property of as-prepared samples were investigated in detail by XRD, SEM, N2 absorption-desorption and DRS. Moreover, their photocatalytic activities on the degradation of rhodamine B were evaluated under visible light irradiation. It was found that the sample dried at 120 °C had the best photocatalytic activity, which was mainly attributed to the highest exposing proportion of {001} facets correspond to BiOCl, largest BET and minimum bandgap. The degradation mechanism was explored that superoxide radicals were mainly contributed to the degradation of chromophore, however, holes and hydroxyl were mainly contributed to the photo degradation. Moreover, holes and hydroxyl dominated the degradation of RhB.
- Guang, Lu,Hui, Wang,Xuejun, Zou
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- Oriented attachment growth of BiOCl nanosheets with exposed {1 1 0} facets and photocatalytic activity of the hierarchical nanostructures
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The formation mechanism of nanosheet assembled BiOCl nanostructures in non-aqueous solvothermal system was investigated through time series experiments. The products obtained at different reaction times were characterized by XRD, SEM and (HR)TEM technique
- Cui, Zhankui,Mi, Liwei,Zeng, Dawen
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- Hollow micro-spherical bismuth oxy-chloride for superior visible light induced dye-sensitized photocatalytic activity and its theoretical insight
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Highly-crystalline BiOCl samples exhibiting hollow microsphere like morphology with exposed (110) crystal facets have been synthesized in the present work. The as-synthesized BiOCl samples were characterized in detail by several sophisticated techniques for proper understanding and subsequent analysis of the phase formation, nature of the chemical bonds existing within the samples, composition, morphology and different properties. Variations in synthesis conditions by varying the synthesis temperature and time duration were performed to compare the changes in phase formation, morphology and catalytic activity of the material. The samples showed effective degradation of toxic Rhodamine B dye under both visible light and UV light irradiation. A detailed mechanism of the photocatalytic activity has been proposed by extensive first principles calculations. The hollow microsphere like morphology along with exposed (110) crystal facets proved beneficial for the superior catalytic activity mediated by dye sensitization under visible light.
- Sarkar, Ratna,Das, Dimitra,Kumar Das, Bikram,Mitra, Anuradha,Das, Nirmalya S.,Sarkar, Subrata,Chattopadhyay, Kalyan K.
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- Enhanced visible light photocatalytic activity of AgBr on {001} facets exposed to BiOCl
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The facet dominated AgBr/BiOCl composites with exposed {001} (BiOCl-001) and {101} (BiOCl-101) facets were prepared by facile solvothermal and chemical precipitation process. Microstructures, morphologies, photoelectron and band gap energy of the as-prepared composites were characterized by various experimental methods. The AgBr/BiOCl heterojunctions showed a much higher photocatalytic performance than pure AgBr and BiOCl in photodegradation of Rhodamine B (RhB) under visible light irradiation. In addition, the AgBr-{001}BiOCl with the mole ratio of 1:2 showed the highest photocatalytic performance with the RhB completely degraded in 15?min. The better photocatalytic performance of AgBr-{001}BiOCl may attribute to the fact that {001} facet of BiOCl was beneficial for the separation of photo-generated carriers and more oxygen vacancy can be formed on the surface {001} facets of BiOCl. Moreover, the photocatalytic mechanism of AgBr-{001}BiOCl composites were also discussed.
- Qi, Yi Ling,Zheng, Yi Fan,Yin, Hao Yong,Song, Xu Chun
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- Solvent-Free Synthesis of Bismuth Oxychloride Microflower/Nanosheet Homojunctions for Photoactivity Enhancement
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Solvent-free synthesis of bismuth-based photocatalysts with hierarchical architectures has been rarely reported yet. Herein, BiOCl hierarchical microflowers (MFs) were prepared via a solvent-free route for the first time, using chlorobutanol as the chlorine source. The reaction temperature (T) plays a key role for formation of MFs. The MFs were formed at T >120 °C and some MFs merged into large nanosheets (LNs). MF/LN homojunctions were constructed because considerable differences in sizes and exposed facets between the MFs and the LNs cause differences in their energy band levels. The sample prepared at 120 °C possesses the highest contents of MFs and homojunctions, specific surface area (SBET, 13 m2 g?1), and photoactivity, indicating the high photoactivity of the sample arises from fabrication of homojunctions as well as the high SBET. This work provides a solvent-free way to simultaneously synthesize BiOCl MFs and homojunctions, which paves an avenue for solvent-free synthesis of other photocatalysts.
- Yao, Hanyu,Li, Haiping,Hu, Tingxia,Hou, Wanguo
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- Investigation of adsorption and photocatalytic activities of: In situ cetyltrimethylammonium bromide-modified Bi/BiOCl heterojunction photocatalyst for organic contaminants removal
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Bi/BiOCl heterojunction was prepared via a hydrothermal method, using cetyltrimethylammonium bromide (CTAB) as a stabilizing agent. The structure and chemical properties of Bi/BiOCl with the three different CTAB contents were thoroughly analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), field-emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM), UV-vis diffuse reflectance spectra (UV-vis DRS), zeta potential, and carbon element analysis, the results indicates that there are some important interactions between CTAB and Bi/BiOCl, resulting in decreasing the band gap of Bi/BiOCl with the increase of CTAB content. Two typical dyes, rhodamine B (RhB) and methyl orange (MO) which has different surface charges, were choosed as the target pollutants. Under the visible light (λ = 420 nm), the photocatalytic efficiency of Bi/BiOCl with a higher CTAB (Bi/BiOCl-a) was 3.72-fold more than that of Bi/BiOCl with a lower CTAB (Bi/BiOCl-c) to remove RhB. Bi/BiOCl heterojunction alone exhibited a poor degradation capability for the MO such as 5% of MO photodegradation with Bi/BiOCl-c. In contrast, MO removal efficiency by the Bi/BiOCl-a was 100%. Hence, the CTAB could play an important role to enhance the removal of dyes. Firstly, CTAB could absorb the target pollutants near the surface of Bi/BiOCl due to the electrostatic attraction and dispersion interaction; then Bi/BiOCl could degrade the pollutants via the in situ h+ or O2- under the visible light. The proposed mechanism was supported by the FTIR and adsorption analysis.
- Li, Wentao,Xiao, Feng,Su, Hang,Wang, Dongsheng,Yang, Xiaofang
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- Core-shell Cd0.2Zn0.8S@BiOX (X = Cl, Br and I) microspheres: A family of hetero-structured catalysts with adjustable bandgaps, enhanced stability and photocatalytic performance under visible light irradiation
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Heterostructures consisting of two semiconductors have merited considerable attention in photocatalytic applications due to synergistic effects in complex redox processes. The incorporation of solid solutions into such architectures can further offer extra variability to control the bandgap. In this study, we report the fabrication of a series of core-shell Cd0.2Zn0.8S@BiOX (X = Cl, Br and I) microspheres via a solvothermal route that lead to enhanced photocatalytic performance under visible light irradiation. By optimizing the synthesis conditions, uniform and porous Cd0.2Zn0.8S@BiOX microspheres were achieved. The products were thoroughly characterized by X-ray diffraction studies, scanning electron microscopy, transmission electron microscopy, photoluminescence studies, absorption measurements and the photodegradation of RhB. Remarkably, the electronic structures of Cd0.2Zn0.8S@BiOX composites can be continuously tuned by varying the composition of BiOX to achieve the best catalytic performance under visible light irradiation. Finally, this greatly enhanced visible-light-driven photocatalytic efficiency was observed in the optimized Cd0.2Zn0.8S@BiOI composites when compared to their single-component counterparts, which may be attributed to increased light absorption and improved electron-hole separation. The photocatalytic mechanism has also been proposed based on the experimental evidences and the theoretical band positions of Cd0.2Zn0.8S@BiOI.
- Zhou, Yannan,Wen, Ting,Chang, Binbin,Yang, Baocheng,Wang, Yonggang
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p. 13709 - 13716
(2016/09/09)
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- Epitaxial growth of silver chloride crystals on bismuth oxychloride
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In this work, studies of morphological and structural characteristics of BiOCl/AgX heterostructures (X = Cl, I) synthesized using ion-exchange reactions have been conducted. It was found that silver chloride (AgCl) crystals precipitating on the surface of
- Bokhonov, Boris B.
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p. 176 - 181
(2015/02/05)
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- Efficient separation of photogenerated electron-hole pairs by the combination of a heterolayered structure and internal polar field in pyroelectric BiOIO3 nanoplates
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Electrify your chemistry! Pyroelectric heterolayered BiOIO3 nanoplates efficiently separate photogenerated electron-hole pairs due to the combined effect of their heterolayered structure and internal polar field (see scheme). Pyroelectric BiOIO3 nanoplates, synthesized by a simple hydrothermal method, were found to possess a superior photocatalytic activity under UV irradiation. Copyright
- Wang, Wenjun,Huang, Baibiao,Ma, Xiangchao,Wang, Zeyan,Qin, Xiaoyan,Zhang, Xiaoyang,Dai, Ying,Whangbo, Myung-Hwan
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supporting information
p. 14777 - 14780
(2013/11/06)
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- Highly efficient C-H oxidative activation by a porous Mn III-porphyrin metal-organic framework under mild conditions
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A simple strategy to rationally immobilize metalloporphyrin sites into porous mixed-metal-organic framework (M'MOF) materials by a metalloligand approach has been developed to mimic cytochrome P450 monooxygenases in a biological system. The synthesized porous M'MOF of [Zn2(MnOH-TCPP)- (DPNI)]·0.5DMF·EtOH·5.5H2O (CZJ-1; CZJ = Chemistry Department of Zhejiang University; TCPP = tetra-kis(4-carboxyphenyl) porphyrin); DPNI = N, N′-di(4-pyridyl)-1, 4, 5, 8-naph- thalenetetracarboxydiimide) has the type of doubly interpenetrated cubic aPo topology in which the basic Zn2-(COO)4 paddle-wheel clusters are bridged by metalloporphyrin to form two-dimensional sheets that are further bridged by the organic pillar linker DPNI to form a three-dimensional porous structure. The porosity of CZJ-1 has been established by both crystal-lographic studies and gas-sorption isotherms. CZJ-1 exhibits significantly high catalytic oxidation of cyclohexane with conversion of 94% to the mixture of cyclohexanone (K) and cyclohexanol (A) (so-called K-A oil) at room temperature. We also provided solid experimental evidence to verify the catalytic reaction that occurred in the pores of the M'MOF catalyst.
- Xie, Ming-Hua,Yang, Xiu-Li,He, Yabing,Zhang, Jian,Chen, Banglin,Wu, Chuan-De
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supporting information
p. 14316 - 14321
(2013/11/06)
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- A facile hydrothermal method to BiSbO4 nanoplates with superior photocatalytic performance for benzene and 4-chlorophenol degradations
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BiSbO4 nanoplates with a large BET specific area has been prepared successfully via a facile hydrothermal reaction from Sb 2O3 and Bi(NO3)3. The effects of reaction conditions and the precursors on the final products were investigated. It is proposed that the redox reaction between Sb2O3 and Bi(NO3)3 plays a pivotal role in the formation of nanocrystalline BiSbO4. The hydrothermally prepared nanocrystalline BiSbO4 was characterized by X-ray diffraction (XRD), N 2-sorption BET surface area, UV-vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The DRS result clarifies that BiSbO4, originally believed to be a visible light responsive photocatalyst, is indeed UV light responsive with a band gap of 3.5 eV. The existence of Bi containing an impurity may be responsible for the visible light response of BiSbO4 prepared via a conventional solid state reaction. BiSbO4 nanoplates prepared via the hydrothermal method showed superior photocatalytic performance for the degradation of benzene and 4-chlorophenol (4-CP) as compared to BiSbO4 prepared via a solid state reaction and Degussa P25. BiSbO4(Hy) nanoplates can be a promising photocatalyst in the treatment of environmental pollution. The Royal Society of Chemistry 2011.
- You, Qingqing,Fu, Yanghe,Ding, Zhengxin,Wu, Ling,Wang, Xuxu,Li, Zhaohui
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p. 5774 - 5780
(2011/08/04)
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