NEW JOURNAL OF CHEMISTRY
·
2018
·Vol. 42
·期 24
·19901-19907
·
IF 3.201
Xin Wang,Yi-Fan Jiang,Ya-Nan Liu,An-Wu Xu
Because of the active components, ultra small size, and the strong metal–support interaction (SMSI) between the metal and the support, noble metal/support nanocatalysts show high catalytic activity in chemical and photochemical reactions. Palladium is one of the most extensively used noble metals due to its outstanding properties. However, the high price and the trend of aggregation are two obvious defects which prevent further application of palladium in large-scale synthesis. Herein, we chose a novel oxide component Er2O3 which can effectively reduce the aggregation of palladium nanoparticles as the support. Thus, a series of highly efficient Er2O3 nanocatalysts with low palladium loading (ranging from 1.25 wt% to 2.25 wt%) were prepared as highly efficient hydrogenation nanocatalysts. Notably, the 1.75 wt% Pd–Er2O3 achieved a remarkable turnover frequency (TOF) value of 9013 h−1 for the hydrogenation of styrene at room temperature and 1 atm H2. The sample can also catalyze the hydrogenation of a variety of functional nitroarenes with excellent catalytic properties using H2 as the reductant, which was probably attributed to the synergistic effect of the strong metal–support interaction (SMSI) and strong chemisorption of H2 on Pd–Er2O3. This work could provide a new strategy and inspiration to prepare noble metal particles loaded on oxide supports with remarkable catalytic performance for various chemical transformations.
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DALTON TRANSACTIONS
·
2018
·Vol. 47
·期 47
·16862-16875
·
IF 4.099
Shijian Zhou,Weiming Jin,Yun Ding,Bo Shao,Bangbang Wang,Xu Hu,Yan Kong
Nowadays, agglomeration and leaching of metal active sites during reaction and recycle processes are considered to be a thorny problem for noble metal-based catalysts. Therefore, to make improvements, nano-gold was selected as a representative research object for many noble metals. In this study, Au nanoparticles (NPs) and magnetic γ-Fe2O3 were intercalated in situ in the walls of MCM-41 via a one-pot hydrothermal method, in which the intercalation process was preceded by co-condensation of tetraethyl orthosilicate (TEOS) with MPTS-Au complexes ((3-mercaptopropyl)-trimethoxysilane (MPTS), HAuCl4·3H2O), and a Fe3O4 sol. By the confinement of silica, Au NPs and γ-Fe2O3 were well dispersed in the walls of MCM-41, the sintering and loss of Au NPs was highly restricted, and the magnetic property of γ-Fe2O3 facilitated the recycling of Au-based catalysts. Additionally, abundant void defects appeared in MCM-41 by assembly of micelles in different sizes and shapes, greatly improving the surface area of target catalysts (>1800 m2 g−1), which provided more opportunities for contact and collision between reactors and gold active sites, effectively solving the problem of mass transportation. As expected, a series FeAu@MCM-41 catalysts showed superior catalytic activity in the reduction of 4-nitrophenol (4-NP) and organic dyes (MB, RhB, and MO), and these catalysts were recycled five times without significant loss of metal species or catalytic activity. This is attributed to the confinement effect of the silica walls and the excellent magnetic properties of γ-Fe2O3. This special structure of FeAu@MCM-41 catalysts provides more insights for designing and fabricating noble metal-based catalysts with desirable performances.
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Nanomaterials
·
2019
·Vol. 9
·期 7
·1009
·
IF 4.034
Juanjuan Yin,Lun Zhang,Tifeng Jiao,Guodong Zou,Zhenhua Bai,Yan Chen,Qingrui Zhang,Meirong Xia,Qiuming Peng
With development of the society, the problem of environmental pollution is becoming more and more serious. There is the urgent need to develop a new type of sustainable green material for degradable pollutants. However, the conventional preparation method is limited by conditions such as cumbersome operation, high energy consumption, and high pollution. Here, a simple method named self-reduction has been proposed, to synthesize highly efficient catalytic nitro compounds and morin self-assembled MXene-Pd nanocomposites. Palladium nanoparticles were grown in situ on MXene nanosheets to form MXene@PdNPs. MXene@PdNPs composites with different reaction times were prepared by adjusting the reduction reaction time. In particular, MXene@PdNPs20 exhibited a high catalytic effect on 4-NP and 2-NA, and the first-order rate constants of the catalysis were 0.180 s−1and 0.089 s−1, respectively. It should be noted that after eight consecutive catalytic cycles, the conversion to catalyze 4-NP was still greater than 94%, and the conversion to catalyze 2-NA was still greater than 91.8%. Therefore, the research of self-assembled MXene@PdNPs nanocomposites has important potential value for environmental management and sustainable development of human health, and provides new clues for the future research of MXene-based new catalyst materials.Keywords:nanocomposites;catalyst;MXene;self-reduction;palladium nanoparticles
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Yuxian Wang,Lulu Chen,Chunmao Chen,Jiaxin Xi,Hongbin Cao,Xiaoguang Duan,Yongbing Xie,Weiyu Song,Shaobin Wang
Metal-free catalysts such as N-doped nanocarbons are sustainable alternatives to metal-based catalysts for the degradation of persistent organic pollutants (POPs), but cost-efficient methods are required for their large-scale synthesis. In this study, a facile and scalable strategy was established for synthesizing layered N-doped nanocarbons via the pyrolysis of β-cyclodextrin (β-CD) and melamine in a N 2 atmosphere. Compared with undoped pyrolyzed β-CD, N-doping led to a 30.3-fold enhancement in the pseudo-first-order rate constant for catalytic ozonation of oxalic acid (OA), and complete degradation of 50 mg/L OA was achieved in 45 min. Apart from the specific surface area boosting from 78.9 to 16.2 m 2 /g after N doping, the OA degradation results and material characterization also suggested that quaternary N was the main active site, which was further validated by density functional theory (DFT) simulations. DFT simulations also suggested that C atoms with high charge densities adjacent to N dopants exhibited considerable potential for the catalytic dissociation of ozone. Electron paramagnetic resonance (EPR), radical quenching, and in situ Raman studies indicated occurrence of surface oxidation pathway apart from the radical-based one. Ozone on the catalyst surface was decomposed into surface-adsorbed atomic oxygen (*O ad ) and free peroxide (*O 2 free ). Both *O ad and OH, which was further evolved on the surface or in bulk solution, contributed to OA destruction. These insights into the catalytic ozonation mechanism on N-doped nanocarbons will advance their practical application to the catalytic degradation of organic pollutants.
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Micro & Nano Letters
·
2019
·Vol. 14
·期 5
·501-504
·
IF 0.975
Ya Liu,Yuqing Miao
The quadrangular (QA) bismuth oxychloride nanoflakes (NFs) were synthesised by a simple solvothermal reaction. They were characterised by scanning electron microscope, transmission electron microscope and X-ray diffractometer. As catalysts, the square NFs exhibited excellent catalytic performance in the reduction of 4-nitrophenol (4-NP) and the degradation of rhodamine B (RhB). The complete reduction of 4-NP to 4-aminophenol was obtained in 30 s and the nearly complete degradation of RhB in 20 min.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2018
·
IF 5.667
Minghua Wang,Yongkang Liu,Longyu Yang,Kuan Tian,Linghao He,Zhihong Zhang,Qiaojuan Jia,Yingpan Song,Shaoming Fang
A series of composites comprising FeO x and TiO 2 nanoparticles uniformly distributed throughout a mesoporous carbon matrix (hereafter denoted as FeO x /TiO 2 @mC nanocomposites) was synthesized by the direct pyrolysis of a bimetallic Fe/Ti-based metal–organic framework at high temperatures (500, 700, and 900 °C). It shows that the as-prepared FeO x /TiO 2 @mC nanocomposites exhibit large specific surface areas and hierarchically micro/mesoporous hybrid structures, further leading to high electron transfer rate. Combining the highly electrocatalytic activity of TiO 2 and FeO x and the good charge-transfer capability of mesoporous carbon, the caused synergism enables the construction of novel and platforms for sensitively detecting 4-nitrophenol (4-NP). After the optimization of sensitive layers and detection conditions, FeO x /TiO 2 @mC 700 (calcined at 700 °C) is found to exhibit high detection ability toward 4-NP owing to its excellent electrochemical performance and electrocatalytic activity. The FeO x /TiO 2 @mC 700 -based electrochemical sensor shows a low limit of detection of 0.183 μM (S/N = 3) within the linear range of 5–310 μM as determined using amperometry toward 4-NP. The proposed method also displays good anti-interference ability, stability, and applicability toward 4-NP determination in environmental water samples. All these results suggest that the components of the MOF-derived binary metal oxide/mesoporous carbon electrocatalyst can function as a novel electrocatalyst for more endeavors into the development of a promising sensing platform for hazardous compounds in the environment.
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JOURNAL OF LUMINESCENCE
·
2018
·
IF 2.732
YaoYao Qu,Guojuan Ren,Liying Yu,Baoya Zhu,Fang Chai,Lihua Chen
Herein, the fluorescent carbon dots (CDs) has been synthesized by hydrothermal method by using ethylene diamine tetraacetic acid (EDTA) as a raw materials. The prepared CDs exhibited bright blue fluorscence excited by 340 nm with the quantum yield as high as 52%. The CDs possess special fluorescence responses to 2-nitrophenol (2-NP) and 4-nitrophenol (4-NP), and the slump of fluorescence was demonstrated by CDs solution in the case of 2-nitrophenol and 4-nitrophenol existence. The detection limit of 2-NP and 4-NP was calculated at 77 nM and 60 nM, respectively. Meanwhile, the color response to 2-NP and 4-NP can be observed from achromatic solution to yellow by naked eye. All in all, the obtained CDs can be applied as fluorescence and colorimetric probe in environmental protection.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2018
·
IF 5.091
Man Yuan,Renzi Yang,Shuoyun Wei,Xiwei Hu,Dan Xu,Jin Yang,Zhengping Dong
Porous organic polymers (POPs) containing nitrogenous substituents have potential practical applications as heterogeneous catalysts based upon controlled porous structure and surface-anchored noble metal nanoparticles (NMNPs). In this work we prepared a POP material from piperazine and cyanuric chloride starting materials (PC-POP). The PC-POP material contains numerous triazinyl moieties, thus rendering the pores hydrophobic. Subsequently, by means of a novel reverse double-solvent approach (RDSA), microdroplets of Pd(AcO) 2 /CH 2 Cl 2 were introduced into the hydrophobic pores of PC-POP in an aqueous environment; Pd(II) was rapidly reduced by NaBH 4 to form ultra-fine Pd NPs and confined within the pores of PC-POP at high dispersity. The extensive porosity and dispersity of the Pd NPs made the active sites readily accessible, and led to efficient mass transfer. Thus, Pd@PC-POP exhibits superior catalytic performance in catalytic reduction of various nitroarenes. Furthermore, Pd@PC-POP has excellent recyclability, without significant loss of activity nor leaching of Pd active sites during 10 successive reaction cycles. This work points to a practical and cost-effective approach to preparation of POP materials, and also for confining ultra-fine NMNPs in POPs for use as catalysts.
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JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 54
·期 1
·323-334
·
IF 2.993
Ma Mingliang,Yang Yuying,Li Wenting,Feng Renjun,Li Zhangwen,Lyu Ping,Ma Yong
Fe 3 O 4 /P(GMA-DVB)/PAMAM/Au microspheres are fabricated to research the catalytic performances to 4-nitrophenol. In the preparation process, Fe 3 O 4 microspheres act as magnetic cores, PAMAM dendrimers growing up on the surface of P(GMA-DVB) polymer work as carriers, and Au nanoparticles serve as catalytic materials. The stability of the prepared microspheres is evaluated by successively catalytic experiments to measure the conversion of 4-nitrophenol, and catalytic efficiency can still maintain up to 78.7% after ten cycles. Moreover, the effects of major factors including the concentration of the prepared microspheres and the temperature of reaction system on the conversion of 4-nitrophenol are also investigated in detail. The manuscript reveals that 4-nitrophenol can be almost converted to 4-aminophenol within 7 min at 45 °C in the case of using 1.0 g/L Fe 3 O 4 /P(GMA-DVB)/PAMAM/Au microspheres. Such excellent catalytic properties are ascribed to the optimum structure of the prepared microspheres, which favors the sufficient contact between Au nanoparticles and 4-nitrophenol. The results and strategies exhibited here provide insight into the preparation of sophisticated structures of catalysts to treat wastewater.
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ACS Applied Materials & Interfaces
·
2015
·
IF 6.723
Tong Yang,Hong Yan Zou,Cheng Zhi Huang
A new heterogeneous catalytic composite composed of nonstoichiometric Cu2–xSe nanoparticles (NPs) with high copper deficiency and graphene oxide (GO) is prepared by coembedding in electrospun nanofibers of a poly(vinylpyrrolidone) (PVP) support, wherein GO in the nanofibers is converted into reduced GO (rGO) via heat treatment. The as-prepared composite Cu2–xSe/rGO/PVP nanofibers have demonstrated superior catalytic activity toward the reduction of a refractory organic compound by taking 4-nitrophenol (4-NP) as an example. In the presence of NaBH4, the Cu2–xSe/rGO/PVP nanofibers display a synergetic effect between Cu2–xSe and rGO in PVP nanofibers compared to their independent components or corresponding nanofibers. Furthermore, the Cu2–xSe/rGO/PVP nanofibers exhibit a favorable water-stable property via heat treatment to solidify the hydrophilic PVP matrix, which makes the composite display good reusability, stability in aqueous solution, and separability from a water medium. This work not only presents a direct, convenient, and effective approach to doping semiconductor nanomaterials into polymer nanofibers but also provides fundamental routes for further investigations about the synergetic effect between different materials based on the platform of electrospun nanofibers.
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JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2015
·Vol. 75
·期 1
·82-89
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IF 1.532
Xiao Zuo-Yi,Huang Shu-Xian,Zhai Shang-Ru,Zhai Bin,Zhang Feng,An Qing-Da
Abstract A one-pot method was introduced to fabricate Ag–SiO 2 hollow composite spheres with developed porosity by employing monodisperse carboxylic-capped polystyrene (PS–COOH) spheres as a hard template. During the synthetic process, Ag + ions were immediately anchored on the surface of the PS–COOH spheres via electrostatic interaction and readily reduced by employing polymethylhydrosiloxane (PMHS) as a reducing agent. At the same time, silica oligomers derived from the hydrolysis of PMHS and TEOS were slowly deposited on the PS–COOH spheres to form solid silica shells. Subsequent decomposition of the PS–COOH spheres in air induced the formation of Ag–SiO 2 hollow spheres. The as-prepared products were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and N 2 absorption–desorption study. The results show that the well-designed composite spheres featured thin and spherical silica shell (~10 nm), large surface area (>240 m 2 g −1 ) and mesopore (6.0–9.0 nm). In addition, the Ag–SiO 2 hollow composite spheres exhibited high catalytic performance toward the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Graphical Abstract A one-pot method was reported to prepare Ag–SiO 2 hollow spheres with well-developed porosity, which exhibited high catalytic performance and durable activity for the reaction of 4-NP to 4-AP.
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SENSORS
·
2013
·Vol. 13
·期 1
·758-768
·
IF 1.953
Qing Lu,Weina Zhang,Zhihui Wang,Guangxia Yu,Yuan Yuan,Yikai Zhou
A facile electrochemical sensor for the determination of nonylphenol (NP) was fabricated in this work. Cetyltrimethylammonium bromide (CTAB), which formed a bilayer on the surface of the carbon paste (CP) electrode, displayed a remarkable enhancement effect for the electrochemical oxidation of NP. Moreover, the oxidation peak current of NP at the CTAB/CP electrode demonstrated a linear relationship with NP concentration, which could be applied in the direct determination of NP. Some experimental parameters were investigated, such as external solution pH, mode and time of accumulation, concentration and modification time of CTAB and so on. Under optimized conditions, a wide linear range from 1.0 × 10−7mol·L−1to 2.5 × 10−5mol·L−1was obtained for the sensor, with a low limit of detection at 1.0 × 10−8mol·L−1. Several distinguishing advantages of the as-prepared sensor, including facile fabrication, easy operation, low cost and so on, suggest a great potential for its practical applications.Keywords:nonylphenol (NP);cetyltrimethylammonium bromide (CTAB);determination;electrochemical sensor
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