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Novel layer-by-layer assembly of rGO-hybridised ZnO sandwich thin films for the improvement of photo-catalysed hydrogen production

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Journal of Energy Chemistry 2016年第2期25卷 334-342页

作者： Swe Jyan Teh Chin Wei Lai sharifah bee abd.hamid Nanotechnology & Catalysis Research Centre (NANOCAT) 3rd Floor Block A Institute of Postgraduate Studies (IPS) University of Malaya 50603 Kuala Lumpur Malaysia

Metal oxide semiconductor materials such as ZnO have tremendous potential as light absorbers for photocatalysed electrodes in the electrochemical reduction of water. Promoters such as rGO have been added to reduce the recombination losses of charge carriers and improve its photoelectrochemical activity. In this study, the effect of layer ordering on the charge transfer properties of rGO-hybridised ZnO sandwich thin films for the photo-catalysed electrochemical reduction of water was investigated. rGO-hybridised ZnO sandwich thin films were prepared via a facile electrode position technique using a layer-by-layer approach. The thin films were analysed using FESEM, XRD, Raman, PL, UV–vis, EIS and CV techniques to investigate its morphological, optical and electrochemical properties. The FESEM images show the formation of distinct layers of rGO and ZnO nanorods/flakes via the layer-by-layer method. XRD confirmed the wurtzite structure of ZnO. PL spectroscopy revealed a reduction of photoemission intensity in the visible region（580 nm） when rGO was incorporated into the ZnO thin film. Among the six thin films prepared, ZnO/rGO showed superior performance compared to the other thin films（0.964 m A/cm） due to the presence of graphene edges which participate as heterogenous electrocatalysts in the photocatalysed electrolysis of water. rGO also acts as electron acceptor, forming an n-p heterojunction which improves the activity of ZnO to oxidise water molecules to O2. EIS revealed that the application of rGO as back contact（rGO/ZnO, rGO/ZnO/rGO） reduces the charge transfer resistance of a semiconductor thin film. Alternatively, rGO as front contact（ZnO/rGO, rGO/ZnO/rGO） improves the photo-catalysed electrolysis of water through the participation of the rGO edges in the chemical activation of water. The findings from this study indicate that the layer ordering significantly affects the thin film＇s electrostatic properties and this understanding can be further advantageous fo

关键词： Heterojunction Layer-by-layer assembly ZnO thin film Photocatalysis

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Eco-toxicity and health risk assessment of polycyclic aromatic hydrocarbons in surface sediments of Burullus Lake in Egypt

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China Geology 2024年第3期7卷 460-468页

作者： Hanan E Osman Mohamed H E El-Morsy Hazem T abd El-hamid Department of Biology Faculty of Applied ScienceUmm Al-Qura UniversityMecca 24382Saudi Arabia Deanship of Scientific Research Umm Al-Qura UniversityMakkah 24372Saudi Arabia National Institute of Oceanography and Fisheries(NIOF) Cairo 11865Egypt Botany and Microbiology Department Faculty of ScienceAl-Azhar UniversityCairo 11651Egypt

Polycyclic aromatic hydrocarbons(PAHs)are ubiquitous environmental contaminants of growing concern due to their potential ecological and human health *** study presents a comprehensive assessment of PAHs contamination in the surface sediments of Burullus Lake,a vital and second largest delta lake in *** aim was to evaluate the eco-toxicity and potential health risks associated with the presence of these *** seven sediment samples were collected from various drains in the southern part of Burullus *** extraction method was employed to extract PAHs(16PAHs)from the sediment ***,target compounds were located using *** results showed that samples contained PAHs levels ranging from 0.038×10^(-6)to 0.459×10^(-6),which is considered heavily polluted by the European standard for PAHs ***,there was no apparent source of PAHs in the ElKhashah drain or the Brinbal Canal,as HPLC found none of the *** most prevalent compound in sediment samples along the study area was *** diagnostic indices in the present study indicated that the hydrocarbons in the region originated from pyrolytic and man-made sources along the drains of Burullus *** principal component analysis(PCA)and diagnostic ratios revealed that coal combustion and pyrolytic sources were responsible for the PAHs contamination in the surface *** non-carcinogenic risk(HI),which is the product of the HQs for the adult and child populations,respectively,was *** values under 1,therefore,demonstrated that they had no carcinogenic effects on human *** and MEQs in the sediments of Burullus Lake do not have a cancer-causing impact on *** the safety of nearby wildlife,aquatic life,and people,all activities that raise petroleum hydrocarbon levels in Burullus Lake must be adequately regulated and *** to the ecological risk assessment,there is little chance that PAHs will be found

关键词： Polycyclic aromatic hydrocarbons Diagnostic indices Toxicity Delta lake sediment Burullus Lake Human health risk Aquatic ecosystem HPLC Coal combustion

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Palladium and carbon synergistically catalyzed room-temperature hydrodeoxygenation(HDO) of vanillyl alcohol–A typical lignin model molecule

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Journal of Energy Chemistry 2017年第1期26卷 8-16页

作者： Qi Wang Neeraj Gupta Guodong Wen sharifah bee abd.hamid Dang Sheng Su School of Materials Science and Engineering University of Science and Technology of China Institute of Metal Research Chinese Academy of Sciences Nanotechnology & Catalysis Research Centre (NANOCAT) University of Malaya IPS Building

Vanillyl alcohol, which is made up of an aromatic ring, an alcoholic hydroxyl group, a phenolic hydroxyl group and a methoxy group, was selected as the model molecule of lignin. Various carbon materials supported Pd catalysts were chosen to catalyze the HDO of vanillyl alcohol. The catalysts were characterized via TEM, TPD, XRD, XPS and CO-chemisorption. It was found that different carbon materials could obviously influence the particle sizes, dispersion and distribution of Pd or PdO particles. Palladium and carbon can synergistically catalyze the room-temperature HDO of vanillyl alcohol even at room temperature, and the carboxyl group was found to be the effective active acid site during the reaction. Possible reaction mechanism was also proposed. The existence of the effective active acid sites on the carbon supports could obviously lower the reaction temperature without decreasing the selectivity, as a result, making the production of renewable fuels by HDO much more economically feasible, which is of much importance. © 2016 Science Press

关键词： Bioconversion Carbon Catalysts Dispersions Molecules Palladium

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Facile preparation of Nd2Zr2O7–ZrO2 nanocomposites as an effective photocatalyst via a new route

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Journal of Energy Chemistry 2017年第2期26卷 315-323页

作者： Sahar Zinatloo-Ajabshir Zahra Zinatloo-Ajabshir Masoud Salavati-Niasari Samira Bagheri sharifah bee abd.hamid Institute of Nano Science and Nano Technology University of KashanKashanP.O.Box.87317-51167I.R.Iran School of Pharmacy Mazandaran University of Medical SciencesSariP.O.Box.486717–887I.R.Iran Nanotechnology&Catalysis Research Centre(NANOCAT) IPS BuildingUniversity of Malaya50603 Kuala LumpurMalaysia

NdZrO–ZrOnanocomposites were prepared via a facile process with propylene glycol as novel connecting agent and benzene tricarboxylic acid as a new complexing agent. The as-obtained NdZrO–ZrOnanocomposites were characterized by transmission electron microscopy（TEM）, UV–vis diffuse reflectance spectroscopy, energy dispersive X-ray microanalysis（EDX）, Fourier transform infrared（FT-IR）spectroscopy, field emission scanning electron microscopy（FESEM）, and X-ray diffraction（XRD）. According to the morphological studies of the as-synthesized nanocomposites, it was found that the shape and particle size of NdZrO–ZrOnanocomposites depended on the space-filling template type, dosage of space-filling template and tricarboxylic acid as complexing agent. NdZrO–ZrOnanocomposites with different shapes and grain sizes have been synthesized. The photocatalytic behavior of as-produced NdZrO–ZrOnanocomposites was also investigated through photodegradation of methylene blue dye and 2-naphthol as water pollutants.

关键词： Photocatalyst Nanomaterials Photodegradation Nanocomposites Electron microscopy

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N-Methylimidazolium perchlorate as a new ionic liquid for the synthesis of bis(pyrazol-5-ol)s under solvent-free conditions

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Chinese Chemical Letters 2016年第1期27卷 104-108页

作者： Nader Ghaffari Khaligh sharifah bee abd.hamid Salam J.J.Titinchi Nanotechnology & Catalysis Research Centre NANOCAT University Malaya Department of Chemistry University of the Western Cape

N-Methylimidazolium perchlorate（[MIm]ClO_4） was synthesized and some of its physico-chemical properties, such as density, surface tension were investigated. A thermo gravimetric analysis（TGA） and solvent performance were also studied. The results show that this ionic liquid is an excellent catalyst for the synthesis of 4,4＇-（arylmethylene）bis（1H-pyrazol-5-ol） derivatives under solvent-free *** method has the advantages of high yield, clean transformation, simple operation and short reaction time. The ionic liquid can be recycled without significant loss of activity.

关键词： Ionic liquid N-Methylimidazolium perchlorate Bis(pyrazol-5-ol)s Recycle

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加热与超声辐照条件下4-(丁二酰亚胺基)-1-丁烷磺酸Brnsted酸催化剂催化吡喃并[4,3-b]吡喃衍生物合成(英文)

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催化学报 2015年第5期36卷 728-733页

作者： Nader Ghaffari Khaligh sharifah bee abd.hamid Nanotechnology & Catalysis Research Centre NANOCAT University Malaya

4-(Succinimido)-1-butane sulfonic acid was shown to be an efficient and reusable Brnsted acid catalyst for the synthesis of pyrano[4,3-b]pyran derivatives using thermal and ultrasonic conditions. The catalyst was prepared by mixing succinimide and 1,4-butanesultone, which is simpler and safer than the preparation of succinimide sulfonic acid. This method has the advantages of high yield, clean reaction, simple methodology, and short reaction time. The catalyst can be recycled without loss of activity.

关键词：吡喃衍生物琥珀酰亚胺超声波照射酸催化剂亚胺基磺酸布朗丁烷

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Effect of diluent and reaction parameter on selective oxidation of propane over MoVTeNb catalyst using nanoflow catalytic reactor

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Journal of Natural Gas Chemistry 2008年第2期17卷 130-134页

作者： Restu Kartiko Widi sharifah bee abdul hamid Robert Schlgl Department of Mathematic and Natural Science University of SurabayaTG 6th floor Raya Kalirungkut 60293SurabayaIndonesia Combinatorial Technology and Catalysis Research Centre University of Malaya50603Kuala LumpurMalaysia combinatorial Technology and Catalysis Research Centre University of Malaya50603Kuala LumpurMalaysia: Fritz-Haber-Institute der Max-Planck-Gesellschaft Faradayweg 4-614195 BerlinGermany

The selective oxidation of propane to acrylic acid over an MoVTeNb mixed oxide catalyst, dried and calcined before reaction has been studied using high-throughput instrumentation, which is called nanoflow catalytic reactor. The effects of catalyst dilution on the catalytic performance of the MoVTeNb mixed oxide catalyst in selective oxidation of propane to acrylic acid were also investigated. The effects of some reaction parameters, such as gas hourly space velocity （GHSV） and reaction temperature, for selective oxidation of propane to acrylic acid over diluted MoVTeNb catalyst have also been studied. The configuration of the nanoflow is shown to be suitable for screen catalytic performance, and its operating conditions were mimicked closely to conventional laboratory as well as to industrial conditions. The results obtained provided very good reproducibility and it showed that preparation methods as well as reaction parameters can play significant roles in catalytic performance of these catalysts.

关键词： selective oxidation propane acrylic acid MoVTeNb mixed oxide catalyst

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采用柠檬酸合成高分散铜催化剂用于选择氢解反应(英文)

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催化学报 2008年第6期29卷 566-570页

作者： Ming-Hoong LOOI Shuk-Tong LEE sharifah bee abd.hamid Combinatorial Technology and Catalysis Research Centre Institute of Postgraduate StudiesUniversity of Malaya50603 Kuala LumpurMalaysia

A highly dispersed Cu catalyst supported on silica was prepared by an incipient wetness impregnation method with citric *** synthesis was studied by nitrogen physisorption,X-ray diffraction,and temperature-programmed reduction by comparing with a reference prepared without citric *** catalyst precursor obtained after impregnation was X-ray *** precursor was readily transformed to crystalline CuO upon *** CuO particles were of uniform size in a highly dispersed state and can be reduced to Cu at a lower *** activity of the Cu catalyst obtained was an order of magnitude higher than that of the reference for the hydrogenolysis of methyl laurate to dodecanol.

关键词：柠檬酸铜催化剂氢解

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Applied bias photon-to-current conversion efficiency of ZnO enhanced by hybridization with reduced graphene oxide

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Journal of Energy Chemistry 2017年第2期26卷 302-308页

作者： sharifah bee abdul hamid Swe Jyan Teh Chin Wei Lai Siglinda Perathoner Gabriele Centi Nanotechnology and Catalysis Research Centre (NANOCAT) University of Malaya Department of Industrial Chemistry University of Messina

The role of reduced graphene oxide（rGO） in the enhancement of photo-conversion efficiency of ZnO films for photoelectrochemical（PEC） water-splitting applications was analyzed. ZnO and rGO-hybridized ZnO（rGO/ZnO） films were prepared via a two-step electrochemical deposition method followed by annealing at 300 °C under argon gas flow. The physical, optical and electrochemical properties of the films were characterized to identify the effect of rGO-hybridization on the applied bias photon-to-current efficiency（ABPE） of ZnO. Scanning electron microscopy and X-ray diffraction indicated the formation of verticallyaligned, wurtzite-phase ZnO nanorods. Diffuse-reflectance UV–visible spectroscopy indicated that rGO-hybridization was able to increase the light absorption range of the rGO/ZnO film. UPS analysis showed that hybridization with rGO increased the band gap of ZnO（3.56 eV） to 3.63 eV for rGO/ZnO sample,which may be attributed to the Burstein–Moss effect. Photoluminescence（PL） spectra disclosed that rGOhybridization suppressed electron-hole recombination due to crystal defects. Linear sweep voltammetry of the prepared thin films showed photocurrent density of 1.0 and 1.8 m A/cm;for ZnO and rGO/ZnO at+0.7 V, which corresponded to an ABPE of 0.55% and 0.95%, respectively. Thus, this report highlighted the multi-faceted role of rGO-hybridization in the enhancement of ZnO photo-conversion efficiency.

关键词： Zinc oxide Photoelectrochemical water-splitting Reduced graphene oxide Photo-conversion efficiency

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高活性多壁碳纳米管/TiO_2纳米复合物光催化剂光催化降解活性黑5染料(英文)

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催化学报 2014年第12期35卷 2014-2019页

作者： sharifah bee abd.hamid Tong Ling Tan Chin Wei Lai Emy Marlina Samsudin Nanotechnology & Catalysis Research Centre(NANOCAT) Institute of Graduate Studies Building University of Malaya 50603 Kuala Lumpur Malaysia

A nanocomposite UV-visible light-responsive multiwalled carbon nanotube (MWCNT)/titanium dioxide(TiO2) nanophotocatalyst was successfully synthesized by a modified sol-gel method using titanium isopropoxide and functionalized MWCNTs as the starting precursors. The photocatalytic activity of the TiO2 and the nanohybrid material was investigated through the photodegradation of Reactive Black 5 dye under ultraviolet light irradiation. X-ray diffraction analysis indicated that anatase phase was obtained for both the pure TiO2 and the MWCNT/TiO2 composite, while Raman spectroscopy confirmed the presence of MWCNTs in the composite. Field emission scanning elec-tron microscopy revealed that TiO2 nanoparticles with an individual diameter of about 10–20 nm were coated on the surface of the MWCNTs. The specific surface areas of the samples were found to be 80 and 181 m2/g for the pure TiO2 and MWCNT/TiO2, respectively. As a result, MWCNT/TiO2 showed better photocatalytic performance than pure TiO2 because the high surface area of MWCNTs enabled them to function as good electron acceptors for the retardation of electron-hole pair recombination.

关键词：多壁碳纳米管纳米复合材料 TiO2 光催化剂光降解活性黑二氧化钛纳米颗粒染料

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