Ghafar Ali

Publications

• 5.38

  Impact points

  Sonochemical Synthesis of Ag/AgCl Nanocubes and Their Efficient Visible-Light-Driven Photocatalytic Performance.

  Deliang Chen, Seung Hwa Yoo, Qingsong Huang, Ghafar Ali, Sung Oh Cho

  Chemistry (Weinheim an der Bergstrasse, Germany). 03/2012;

  A novel one-step sonochemical approach to synthesize a plasmonic photocatalyst of AgCl nanocubes (ca. 115 nm in edge length) with a small amount of Ag metal species is presented. The nanoscale Ag/AgCl hybrid photocatalysts with cubic morphology are readily formed under ambient ultrasonic conditions ... [more] A novel one-step sonochemical approach to synthesize a plasmonic photocatalyst of AgCl nanocubes (ca. 115 nm in edge length) with a small amount of Ag metal species is presented. The nanoscale Ag/AgCl hybrid photocatalysts with cubic morphology are readily formed under ambient ultrasonic conditions and neither external heat treatment nor reducing agents are required. The size of the Ag/AgCl photocatalysts could be controlled by changing the concentrations of Ag(+) ions and polyvinylpyrrolidone molecules in precursor solutions. The compositions, microstructures, influencing factors, and possible growth mechanism of the Ag/AgCl hybrid nanocubes were systematically investigated. The Ag/AgCl photocatalysts show excellent photocatalytic performance for degradation of various dye molecules under visible light.
• 2.89

  Impact points

  Improvement in the photoelectrochemical responses of PCBM/TiO2 electrode by electron irradiation

  Seung Hwa Yoo, Jong Min Kum, Ghafar Ali, Sung Hwan Heo, Sung Oh Cho

  Nanoscale Research Letters. 03/2012; 7(142).

  The photoelectrochemical (PEC) responses of electron-irradiated [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/TiO2 electrodes were evaluated in a PEC cell. By coating PCBM on TiO2 nanoparticle film, the light absorption of PCBM/TiO2 electrode has expanded to the visible light region and improved... [more] The photoelectrochemical (PEC) responses of electron-irradiated [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/TiO2 electrodes were evaluated in a PEC cell. By coating PCBM on TiO2 nanoparticle film, the light absorption of PCBM/TiO2 electrode has expanded to the visible light region and improved the PEC responses compared to bare TiO2 electrode. The PEC responses were further improved by irradiating an electron beam on PCBM/TiO2 electrodes. Compared to non-irradiated PCBM/TiO2 electrodes, electron irradiation increased the photocurrent density and the open-circuit potential of PEC cells by approximately 90% and approximately 36%, respectively at an optimum electron irradiation condition. The PEC responses are carefully evaluated correlating with the optical and electronic properties of electron-irradiated PCBM/TiO2 electrodes.
• 3.14

  Impact points

  A novel route to large-scale and robust free-standing TiO2 nanotube membranes based on N2 gas blowing combined with methanol wetting.

  Ghafar Ali, Seung Hwa Yoo, Jong Min Kum, Yong Nam Kim, Sung Oh Cho

  Nanotechnology. 06/2011; 22(24):245602.

  We present a novel and straightforward approach to fabricate large-scale and robust free-standing TiO(2) nanotube (TNT) membranes. Simply by blowing N(2) gas onto as-anodized TNTs that are wetted with methanol, free-standing TNT membranes are produced. The approach also provides homogeneous and hone... [more] We present a novel and straightforward approach to fabricate large-scale and robust free-standing TiO(2) nanotube (TNT) membranes. Simply by blowing N(2) gas onto as-anodized TNTs that are wetted with methanol, free-standing TNT membranes are produced. The approach also provides homogeneous and honeycomb-like Ti substrates after the detachment of TNT membranes. Through the second anodization of the honeycomb-like Ti substrates following the N(2) blowing, TNT membranes comprising hexagonally close-packed and regularly ordered TNTs with clear open ends can be achieved. Characterization of the free-standing TNT membranes using Raman spectroscopy and a high-resolution transmission electron microscope reveals that anatase TiO(2) and crystalline graphitic carbon are embedded in the bottom surface of the free-standing TNT membranes.

• Novel microstructural growth in the surface of Inconel 625 by the addition of SiC under electron beam melting

  M. Ahmad, G. Ali, E. Ahmed, M. A. Haq, J. I. Akhter

  Applied Surface Science. 01/2011; 257(17):7405-7410.

  Electron beam melting is being used to modify the microstructure of the surfaces of materials due to its ability to cause localized melting and supercooling of the melt. This article presents an experimental study on the surface modification of Ni-based superalloy (Inconel 625) reinforced with SiC c... [more] Electron beam melting is being used to modify the microstructure of the surfaces of materials due to its ability to cause localized melting and supercooling of the melt. This article presents an experimental study on the surface modification of Ni-based superalloy (Inconel 625) reinforced with SiC ceramic particles under electron beam melting. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction techniques have been applied to characterize the resulted microstructure. The results revealed growth of novel structures like wire, rod, tubular, pyramid, bamboo and tweezers type morphologies in the modified surface. In addition to that fibrous like structure was also observed. Formation of thin carbon sheet has been found at the regions of decomposed SiC. Electron beam modified surface of Inconel 625 alloy has been hardened twice as compared to the as-received samples. Surface hardening effect may be attributed to both the formation of the novel structures as well as the introduction of Si and C atom in the lattice of Inconel 625 alloy. (C) 2011 Elsevier B. V. All rights reserved.

• Improved conversion efficiency of CdS quantum dot-sensitized TiO(2) nanotube-arrays using CuInS(2) as a co-sensitizer and an energy barrier layer

  C. Chen, G. Ali, S. H. Yoo, J. M. Kum, S. O. Cho

  Journal of Materials Chemistry. 01/2011; 21(41):16430-16435.

  A thin layer of CuInS(2) and CdS quantum dots (QDs) is deposited on TiO(2) nanotube arrays (TNTs) to form CdS/CuInS(2)/TNTs photoelectrodes. The CuInS(2) layer is prepared by a successive ionic layer absorption and reaction method, and the CdS QDs are deposited by a chemical bath deposition method. ... [more] A thin layer of CuInS(2) and CdS quantum dots (QDs) is deposited on TiO(2) nanotube arrays (TNTs) to form CdS/CuInS(2)/TNTs photoelectrodes. The CuInS(2) layer is prepared by a successive ionic layer absorption and reaction method, and the CdS QDs are deposited by a chemical bath deposition method. The CuInS(2) layer acts as both a co-sensitizer and an energy barrier layer between TNTs and CdS QDs. The deposited CuInS(2) layer significantly extends the visible-light response of CdS-sensitized TNTs into 500-700 nm wavelength range. As a consequence, the photoelectrochemical response of the CdS/CuInS(2)/TNTs electrodes is much improved compared with CdS sensitized TNTs. The CdS/CuInS(2)/TNTs electrodes exhibit a maximum power conversion efficiency of 7.3%, which is a 120% improvement compared with the highest efficiency of 3.3% for CdS/TNTs electrodes in our study. The improved efficiency is mainly due to the increased absorbance and the reduced recombination between the photoinjected electrons and the redox ions from the electrolyte, resulting from the formation of a CuInS(2) layer.
• 2.89

  Impact points

  Improved conversion efficiency of Ag2S quantum dot-sensitized solar cells based on TiO2 nanotubes with a ZnO recombination barrier layer.

  Chong Chen, Yi Xie, Ghafar Ali, Seung Hwa Yoo, Sung Oh Cho

  Nanoscale research letters. 01/2011; 6(1):462.

  ABSTRACT: We improve the conversion efficiency of Ag2S quantum dot (QD)-sensitized TiO2 nanotube-array electrodes by chemically depositing ZnO recombination barrier layer on plain TiO2 nanotube-array electrodes. The optical properties, structural properties, compositional analysis, and photoelectroc... [more] ABSTRACT: We improve the conversion efficiency of Ag2S quantum dot (QD)-sensitized TiO2 nanotube-array electrodes by chemically depositing ZnO recombination barrier layer on plain TiO2 nanotube-array electrodes. The optical properties, structural properties, compositional analysis, and photoelectrochemistry properties of prepared electrodes have been investigated. It is found that for the prepared electrodes, with increasing the cycles of Ag2S deposition, the photocurrent density and the conversion efficiency increase. In addition, as compared to the Ag2S QD-sensitized TiO2 nanotube-array electrode without the ZnO layers, the conversion efficiency of the electrode with the ZnO layers increases significantly due to the formation of efficient recombination layer between the TiO2 nanotube array and electrolyte.
• 3.14

  Impact points

  Improved conversion efficiency of CdS quantum dots-sensitized TiO2 nanotube array using ZnO energy barrier layer.

  Chong Chen, Yi Xie, Ghafar Ali, Seung Hwa Yoo, Sung Oh Cho

  Nanotechnology. 01/2011; 22(1):015202.

  We report that the use of a chemically deposited ZnO energy barrier between a CdS quantum dot sensitizer and TiO(2) nanotubes (TNTs) can improve the efficiency of quantum dots-sensitized solar cells (QDSCs). The experimental results show that the formation of the ZnO layers over TNTs significantly i... [more] We report that the use of a chemically deposited ZnO energy barrier between a CdS quantum dot sensitizer and TiO(2) nanotubes (TNTs) can improve the efficiency of quantum dots-sensitized solar cells (QDSCs). The experimental results show that the formation of the ZnO layers over TNTs significantly improved the performances of the CdS QDSCs based on the TNTs electrodes. In particular, a maximum photoconversion efficiency of 4.6% was achieved for the CdS/ZnO/TNTs electrode under UV-visible light illumination, corresponding to an increase of 43.7% as compared to the CdS/TNTs electrode without the ZnO layers. The improved CdS QDSCs efficiency is attributed to the suppressed recombination of photoinjected electrons with redox ions from the electrolyte resulting from the ZnO energy barrier layers.
• 2.89

  Impact points

  Fabrication of complete titania nanoporous structures via electrochemical anodization of Ti.

  Ghafar Ali, Chong Chen, Seung Hwa Yoo, Jong Min Kum, Sung Oh Cho

  Nanoscale research letters. 01/2011; 6(1):332.

  ABSTRACT: We present a novel method to fabricate complete and highly oriented anodic titanium oxide (ATO) nano-porous structures with uniform and parallel nanochannels. ATO nano-porous structures are fabricated by anodizing a Ti-foil in two different organic viscous electrolytes at room temperature ... [more] ABSTRACT: We present a novel method to fabricate complete and highly oriented anodic titanium oxide (ATO) nano-porous structures with uniform and parallel nanochannels. ATO nano-porous structures are fabricated by anodizing a Ti-foil in two different organic viscous electrolytes at room temperature using a two-step anodizing method. TiO2 nanotubes covered with a few nanometer thin nano-porous layer is produced when the first and the second anodization are carried out in the same electrolyte. However, a complete titania nano-porous (TNP) structures are obtained when the second anodization is conducted in a viscous electrolyte when compared to the first one. TNP structure was attributed to the suppression of F-rich layer dissolution between the cell boundaries in the viscous electrolyte. The structural morphologies were examined by field emission scanning electron microscope. The average pore diameter is approximately 70 nm, while the average inter-pore distance is approximately 130 nm. These TNP structures are useful to fabricate other nanostructure materials and nanodevices.

• Sonication-assisted synthesis of CdS quantum-dot-sensitized TiO2 nanotube arrays with enhanced photoelectrochemical and photocatalytic activity.

  Yi Xie, Ghafar Ali, Seung Hwa Yoo, Sung Oh Cho

  ACS applied materials & interfaces. 10/2010; 2(10):2910-4.

  A sonication-assisted sequential chemical bath deposition (S-CBD) approach is presented to uniformly decorate CdS quantum dots (QDs) on self-organized TiO2 nanotube arrays (TNTAs). This approach avoids the clogging of CdS QDs at the TiO2 nanotube mouth and promotes the deposition of CdS QDs into the... [more] A sonication-assisted sequential chemical bath deposition (S-CBD) approach is presented to uniformly decorate CdS quantum dots (QDs) on self-organized TiO2 nanotube arrays (TNTAs). This approach avoids the clogging of CdS QDs at the TiO2 nanotube mouth and promotes the deposition of CdS QDs into the nanotubes as well as on the tube walls. The photoelectrochemical and photocatalytic properties of the resulting CdS-decorated TNTAs were explored in detail. In comparison with a classical S-CBD approach, the sonication-assisted technique showed much enhancement in the photoelectrochemical and photocatalytic activities of the CdS QDs-sensitized TNTAs.
• 1.63

  Impact points

  Novel structure formation at the bottom surface of porous anodic alumina fabricated by single step anodization process.

  Ghafar Ali, Maqsood Ahmad, Javed Iqbal Akhter, Muhammad Maqbool, Sung Oh Cho

  Micron (Oxford, England : 1993). 08/2010; 41(6):560-4.

  A simple approach for the growth of long-range highly ordered nanoporous anodic alumina film in H(2)SO(4) electrolyte through a single step anodization without any additional pre-anodizing procedure is reported. Free-standing porous anodic alumina film of 180 microm thickness with through hole morph... [more] A simple approach for the growth of long-range highly ordered nanoporous anodic alumina film in H(2)SO(4) electrolyte through a single step anodization without any additional pre-anodizing procedure is reported. Free-standing porous anodic alumina film of 180 microm thickness with through hole morphology was obtained. A simple and single step process was used for the detachment of alumina from aluminum substrate. The effect of anodizing conditions, such as anodizing voltage and time on the pore diameter and pore ordering is discussed. The metal/oxide and oxide/electrolyte interfaces were examined by high resolution scanning transmission electron microscope. The arrangement of pores on metal/oxide interface was well ordered with smaller diameters than that of the oxide/electrolyte interface. The inter-pore distance was larger in metal/oxide interface as compared to the oxide/electrolyte interface. The size of the ordered domain was found to depend strongly upon anodizing voltage and time.

• MICROSTRUCTURE EVOLUTION DURING BONDING OF Al-Fe-Ce ALLOY WITH ZIRCALOY-4 USING Cu AND Zn INTERLAYERS

  M. Ahmad, T. I. Khan, G. Ali, J. I. Akhter

  Reviews on Advanced Materials Science. 01/2010; 26(1-2):43-47.

  Bonding of Al-Fe-Ce alloy with Zircaloy-4 was carried out using Cu and Zn interlayers. Microstructural characterization was done using scanning electron microscopy and chemical composition of the phases was determined by energy dispersive X-ray spectroscopy. Formation of layered structure was observ... [more] Bonding of Al-Fe-Ce alloy with Zircaloy-4 was carried out using Cu and Zn interlayers. Microstructural characterization was done using scanning electron microscopy and chemical composition of the phases was determined by energy dispersive X-ray spectroscopy. Formation of layered structure was observed in the diffusion zone of bonded structure of Al-Fe-Ce with Zircaloy-4 using Cu as an interlayer. Microhardness of different layers was determined. The results indicate that hardness of the AlZr phase is higher than the Al(2)Zr(3). Microhardness of the bonded alloys also increased due to the small addition of Cu in the lattice. Microhardness of the bonded alloy did not change when the bonding of Al-Fe-Ce with Zircaloy-4 was carried out using Zn coating as an interlayer and a few microcracks were observed in the diffusion zone.

• Nanocrystals formation and intense, green emission in thermally annealed AlN:Ho films for microlaser cavities and photonic applications

  M. Maqbool, G. Ali, S. O. Cho, I. Ahmad, M. Mehmood, M. E. Kordesch

  Journal of Applied Physics. 01/2010; 108(4).

  Plasma magnetron sputtered thin films of AlN:Ho deposited on flat silicon substrates and optical fiber were characterized and analyzed for structural changes after thermal annealing at 1173 K for 40 min, by atomic force microscopy (AFM). The films grown, at liquid nitrogen temperature, on silicon su... [more] Plasma magnetron sputtered thin films of AlN:Ho deposited on flat silicon substrates and optical fiber were characterized and analyzed for structural changes after thermal annealing at 1173 K for 40 min, by atomic force microscopy (AFM). The films grown, at liquid nitrogen temperature, on silicon substrates were amorphous while those deposited around optical fiber were crystalline. The films were also investigated for any change in the luminescence when thermal activation was performed for 40 min in a nitrogen atmosphere. The AFM analysis identified the existence of crystalline structures in parts of the films after thermal annealing. The x-ray diffraction could not provide those results. The films around optical fiber were crystalline even deposited at liquid nitrogen temperature. Clearly, amorphous films are hard to achieve on smaller substrate size. Direct observation of green emission is possible with naked eye, when the thermally annealed films are studied under cathodoluminescence. The green emission occurs at 549 nm as a result from (5)S(2) -> (5)I(8) transition in Ho(3+) that enhanced with thermal activation, making it a very useful candidate for photonic and optical devices applications. (C) 2010 American Institute of Physics. [doi:10.1063/1.3478770]

• Characterization of Cobalt Nanowires Fabricated in Anodic Alumina Template Through AC Electrodeposition

  G. Ali, M. Ahmad, J. I. Akhter, K. Maaz, S. Karim, M. Maqbool, S. G. Yang

  Ieee Transactions on Nanotechnology. 01/2010; 9(2):223-228.

  Cobalt nanowires were fabricated by alternating current electrodeposition using anodic porous alumina template. Diameter of the pores was controlled by the pore widening time. Effect of pore widening time on the magnetic properties and microstructure of the nanowires was investigated. High-resolutio... [more] Cobalt nanowires were fabricated by alternating current electrodeposition using anodic porous alumina template. Diameter of the pores was controlled by the pore widening time. Effect of pore widening time on the magnetic properties and microstructure of the nanowires was investigated. High-resolution scanning transmission electron microscopy was used to study the morphology of the pores as well as nanowires. Magnetic properties were measured by vibrating sample magnetometer at room temperature, and were found to be size-dependent. When the field was applied parallel to the nanowires, coercivity of the nanowires reaches to the maximum value similar to 2200 Oe for 10 min pore widening time. Coercivity decreases linearly with further increase in the pore widening time. In the case, when the field was applied perpendicular to the nanowires, coercivity was found to decrease monotonically when the pore widening time was increased from 0 to 10 min.
• 2.89

  Impact points

  Stable Field Emitters for a Miniature X-ray Tube Using Carbon Nanotube Drop Drying on a Flat Metal Tip.

  Sunghwan Heo, Aamir Ihsan, Seunghwa Yoo, Ghafar Ali, Sungoh Cho

  Nanoscale research letters. 01/2010; 5(4):720-4.

  Stable carbon nanotube (CNT) field emitters for a vacuum-sealed miniature X-ray tube have been fabricated. The field emitters with a uniform CNT coating are prepared by a simple drop drying of a CNT mixture solution that is composed of chemically modified multi-walled CNTs, silver nanoparticles, and... [more] Stable carbon nanotube (CNT) field emitters for a vacuum-sealed miniature X-ray tube have been fabricated. The field emitters with a uniform CNT coating are prepared by a simple drop drying of a CNT mixture solution that is composed of chemically modified multi-walled CNTs, silver nanoparticles, and isopropyl alcohol on flat tungsten tips. A highly thermal- and electrical-conductive silver layer strongly attaches CNTs to the tungsten tips. Consequently, the field emitters exhibit good electron emission stability: continuous electron emission of around 100 μA at 2.3 V/μm has stably lasted over 40 h even at non-high vacuum ambient (~10-3 Pa).

• Microstructure evolution during surface alloying of ductile iron and austempered ductile iron by electron beam melting

  A. Gulzar, J. I. Akhter, M. Ahmad, G. Ali, M. Mahmood, M. Ajmal

  Applied Surface Science. 01/2009; 255(20):8527-8532.

  Alloying and microstructural modi. cation of surfaces by electron beam has become popular to tailor the surface properties of materials. Surface modi. cation of as-received ductile iron, Ni-plated ductile iron and Ni-plated austempered ductile iron was carried out by electron beam melting to improve... [more] Alloying and microstructural modi. cation of surfaces by electron beam has become popular to tailor the surface properties of materials. Surface modi. cation of as-received ductile iron, Ni-plated ductile iron and Ni-plated austempered ductile iron was carried out by electron beam melting to improve the surface properties. Martensitic structure evolved in the heat affected zone and ledeburite structure was produced in the molten zone of the ductile iron. Microhardness of the melted specimens enhanced considerably as compared to the as-received samples. However the microhardness of melted Ni-plated samples is lower than that of the unplated specimens. X-ray diffraction clearly revealed the formation of an austenite and Fe(3)C phases in the electron beam molten zone. The broadening of peaks suggests refinement of the microstructure as well as internal stresses generated during electron beam melting. (C) 2009 Elsevier B. V. All rights reserved.

• Diffusion bonding of Ti coated Zircaloy-4 and 316-L stainless steel

  J. I. Akhter, M. Ahmad, G. Ali

  Materials Characterization. 01/2009; 60(3):193-196.

  Diffusion bonding of Zircaloy-4 and Type 316-L stainless steel was carried out by coating the joining surfaces with Ti to minimize the interlayer effect. Bonding heat treatments were carried out in vacuum at 1000 degrees C for 4 h and 1050 degrees C for 1 h. The microstructure of the diffusion zone ... [more] Diffusion bonding of Zircaloy-4 and Type 316-L stainless steel was carried out by coating the joining surfaces with Ti to minimize the interlayer effect. Bonding heat treatments were carried out in vacuum at 1000 degrees C for 4 h and 1050 degrees C for 1 h. The microstructure of the diffusion zone was investigated by scanning electron microscopy and the phases in the diffusion zone were analyzed by energy dispersive spectroscopy. It is observed that Ti coating at the interface produced a dendritic structure in the diffusion zone formed in the Zircaloy-4. The concentration of the dendrites increases with an increase in bonding temperature. (C) 2008 Elsevier Inc. All rights reserved.

• Microstructure and hardness studies of electron beam melted surface of mild steel

  M. Ahmad, M. A. Haq, E. Ahmed, G. Ali, J. I. Akhter, M. Iqbal

  Applied Surface Science. 01/2009; 255(13-14):6721-6723.

  Electron beam surface melting of mild steel with the addition of Ni and SiC is carried out to improve its surface properties. Microstructure of the electron beam molten surface is characterized by scanning electron microscope. Phases are determined using energy dispersive spectroscopy and X-ray diff... [more] Electron beam surface melting of mild steel with the addition of Ni and SiC is carried out to improve its surface properties. Microstructure of the electron beam molten surface is characterized by scanning electron microscope. Phases are determined using energy dispersive spectroscopy and X-ray diffraction techniques. During electron beam melting SiC dissociated partially, interacted with liquid alloy and resulted in martensitic phases after solidi. cation. Maximum hardness is achieved in electron beam molten zone. It is concluded that the formation of martensitic phase and the presence of Si and Ni in the solid solution are responsible for increase in hardness in the molten zone. (C) 2009 Elsevier B.V. All rights reserved.

• Diameter dependent failure current density of gold nanowires

  S. Karim, K. Maaz, G. Ali, W. Ensinger

  Journal of Physics D-Applied Physics. 01/2009; 42(18).

  Failure current density of single gold nanowires is investigated in this paper. Single wires with diameters ranging from 80 to 720 nm and length 30 mu m were electrochemically deposited in ion track-etched single-pore polycarbonate membranes. The maximum current density was investigated while keepin... [more] Failure current density of single gold nanowires is investigated in this paper. Single wires with diameters ranging from 80 to 720 nm and length 30 mu m were electrochemically deposited in ion track-etched single-pore polycarbonate membranes. The maximum current density was investigated while keeping the wires embedded in the polymer matrix and ramping up the current until failure occurred. The current density is found to increase with diminishing diameter and the wires with a diameter of 80 nm withstand 1.2 x 10(12) A m(-2) before undergoing failure. Possible reasons for these results are discussed in this paper.
• 2.89

  Impact points

  Synthesis and Photocatalytic Activity of Anatase TiO2 Nanoparticles-coated Carbon Nanotubes.

  Yi Xie, Sunghwan Heo, Seunghwa Yoo, Ghafar Ali, Sungoh Cho

  Nanoscale research letters. 01/2009; 5(3):603-7.

  A simple and straightforward approach to prepare TiO2-coated carbon nanotubes (CNTs) is presented. Anatase TiO2 nanoparticles (NPs) with the average size ~8 nm were coated on CNTs from peroxo titanic acid (PTA) precursor even at low temperature of 100 °C. We demonstrate the effects of CNTs/TiO2 mola... [more] A simple and straightforward approach to prepare TiO2-coated carbon nanotubes (CNTs) is presented. Anatase TiO2 nanoparticles (NPs) with the average size ~8 nm were coated on CNTs from peroxo titanic acid (PTA) precursor even at low temperature of 100 °C. We demonstrate the effects of CNTs/TiO2 molar ratio on the adsorption capability and photocatalytic efficiency under UV-visible irradiation. The samples showed not only good optical absorption in visible range, but also great adsorption capacity for methyl orange (MO) dye molecules. These properties facilitated the great enhancement of photocatalytic activity of TiO2 NPs-coated CNTs photocatalysts. The TiO2 NPs-coated CNTs exhibited 2.45 times higher photocatalytic activity for MO degradation than that of pure TiO2.

• Evolution of microstructure and non-equilibrium phases in electron beam treated Zr55Cu30Al10Ni5 bulk amorphous alloy

  N. H. Tariq, M. Iqbal, M. A. Shaikh, J. Akhter, M. Ahmad, G. Ali, Z. Q. Hu

  Journal of Alloys and Compounds. 01/2008; 460(1-2):258-262.

  Electron beam (EB) is becoming very popular for the modification of the surfaces as it involves localized melting and fast cooling which helps in achieving the non-equilibrium phases as well as fine microstructure. Surface modification of Zr-based amorphous alloy Zr55Cu30Al10Ni5 has been carried out... [more] Electron beam (EB) is becoming very popular for the modification of the surfaces as it involves localized melting and fast cooling which helps in achieving the non-equilibrium phases as well as fine microstructure. Surface modification of Zr-based amorphous alloy Zr55Cu30Al10Ni5 has been carried out by EB melting. Differential scanning calorimetry (DSC) was employed to determine the supercooled liquid region and activation energy of crystallization. The as-cast and modified surfaces of amorphous alloy at different beam conditions were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) techniques. Various phases like NiZr2, CuZr2 and Cu10Zr7 were identified which resulted in the enhancement of hardness of the modified alloy surface. (C) 2007 Elsevier B.V. All rights reserved.