Development and characterization of an aerosol time-of-flight mass spectrometer with increased detection efficiency

This paper describes the development and characterization studies of a more efficient aerosol time-of-flight mass spectrometer (ATOFMS), showing results for the on-line detection and determination of the size and chemical composition of single fine (100-300 nm) and ultrafine (<100 nm) particles. An aerodynamic lens inlet was implemented, replacing the converging nozzle inlet used on conventional ATOFMS instruments. In addition, the light scattering region was modified to enhance the scattering signals for smaller particles. Polystyrene latex spheres (PSL) with aerodynamic diameters ranging from 95 to 290 nm were used to characterize the particle sizing efficiency (product of particle transmission efficiency and particle scattering efficiency), particle detection efficiency (product of particle sizing efficiency and particle hit rate), and particle beam profile and perform instrument calibration. At number concentrations of <20 particles/cm(3), the particle sizing efficiencies were determined to be approximately 0.5% for 95 nm and approximately 47% for 290-nm PSL particles, while the particle detection efficiencies were measured to be approximately 0.3% for 95 nm and 44% for 290-nm PSL particles. This represents a significant increase (i.e., at least 3 orders of magnitude) in detection efficiencies for smaller particles over the conventional ATOFMS. In addition, the beam profiles for PSL particles of various sizes were measured in the ion source of the mass spectrometer and follow a Gaussian distribution with a full width at half-maximum of approximately 0.35 mm. The resulting higher detection efficiencies allow ATOFMS to obtain higher temporal resolution measurements of the composition of fine and ultrafine individual particles as demonstrated in initial ambient measurements in La Jolla, CA. At typical ambient particle number concentrations of 10(2)-10(3) particles/cm(3), approximately 30 000 particles with aerodynamic diameters of <300 nm were detected with average 24-h hit rates of 30% for particles between 50 and 300 nm. This advancement, allowing for high temporal resolution measurements of the composition of smaller particles with higher efficiency, adds to a growing number of instruments that can chemically characterize individual fine and ultrafine particles, with the goal of providing new insights into a number of areas including environmental and material sciences, health effects studies, industrial hygiene, and national security.     

超细粒子氧化铝的制备

本文讨论了用超临界流体干燥混凝胶制备氧化铝超细粒子的影响因素；一类为超临界流体的影响因素．其甲温度和压力具有明显的影响，有一较台适的超临界温度达最大比表面积；但超临界压力越低，比表面积越大。加热速率几乎没有影响。另一类为制备混凝胶的影响因素，包括水解温度、加水比例．异丙醇铝固体浓度等均有一最佳制备条件。     

Development of photocatalytic TiO2 nanofibers by electrospinning and its application to degradation of dye pollutants

We have developed photocatalytic TiO2 nanofibers for the treatment of organic pollutants by using electrospinning method. We found that the optimized electrospinning conditions (electric field and flow rate) were 0.9 kV cm(-1) and 50 microL min(-1). After annealing at 550 degrees C for 30 min, we fabricated TiO2 nanofibers (average 236 nm thick) with anatase crystalline phase. To increase photocatalytic activity and effective surface area, we coated photocatalytic TiO2 particles on the TiO2 nanofibers by using sol-gel method. The degradation rate (k'=85.4x10(-4) min(-1)) of composite TiO2 was significantly higher than that (15.7x10(-4) min(-1)) of TiO2 nanofibers and that (14.3x10(-4) min(-1)) of TiO2 nanoparticles by the sol-gel method. Therefore, we suggested that the composite TiO2 of nanofibers and nanoparticles be suitable for the degradation of organic pollutants.     

Microwave plasma synthesis of carbon-supported ultrafine metal particles

Microwave plasma decomposition of metal carbonyls has been used to synthesize a series of carbon-supported monometallic (Fe, Co) and bimetallic (Co-Mo) materials. The average metal particle diameters in all cases were less than 10 nm. By using 10% H₂/Ar instead of pure Ar as a carrier gas, the mean particle diameters could be decreased to less than 2 nm. Although the distribution of particles is slightly broader than those generated by other nanoparticle synthesis methods, the mean diameter of the particles generated using 10% H₂/Ar is as small as any previously reported for Fe-, Co-, Ni-, or Mo-containing compounds. The ultrafine metal particles were dispersed on moderate surface area amorphous carbon support matrixes derived from the concomitant microwave decomposition of the toluene solvent.     

Structure, morphology and magnetic properties of Mg((x))Zn((1 - x))Fe2O4 ferrites prepared by polyol and aqueous co-precipitation methods: a low-toxicity alternative to Ni((x))Zn((1 - x))Fe2O4 ferrites

The synthesis and properties of Mg((x))Zn((1 - x))Fe(2)O(4) spinel ferrites as a low-toxicity alternative to the technologically significant Ni((x))Zn((1 - x))Fe(2)O(4) ferrites are reported. Ferrite nanoparticles have been formed through both the polyol and aqueous co-precipitation methods that can be readily adapted to industrial scale synthesis to satisfy the demand of a variety of commercial applications. The structure, morphology and magnetic properties of Mg((x))Zn((1 - x))Fe(2)O(4) were studied as a function of composition and particle size. Scanning electron microscopy images show particles synthesised by the aqueous co-precipitation method possess a broad size distribution (i.e. ～ 80-120 nm) with an average diameter of the order of 100 nm ± 20 nm and could be produced in high process yields of up to 25 g l(-1). In contrast, particles synthesised by the polyol-based co-precipitation method possess a narrower size distribution with an average diameter in the 30 nm ± 5 nm range but are limited to smaller yields of ～ 6 g l(-1). Furthermore, the polyol synthesis method was shown to control average particle size by varying the length of the glycol surfactant chain. Particles prepared by both methods are compared with respect to their phase purity, crystal structure, morphology, magnetic properties and microwave properties.     

Surface anisotropy broadening of the energy barrier distribution in magnetic nanoparticles

The effect of surface anisotropy on the distribution of energy barriers in magnetic fine particles of nanometer size is discussed within the framework of the Tln(t/τ(0)) scaling approach. The comparison between the distributions of the anisotropy energy of the particle cores, calculated by multiplying the volume distribution by the core anisotropy, and of the total anisotropy energy, deduced by deriving the master curve of the magnetic relaxation with respect to the scaling variable Tln(t/τ(0)), enables the determination of the surface anisotropy as a function of the particle size. We show that the contribution of the particle surface to the total anisotropy energy can be well described by a size-independent value of the surface energy per unit area which permits the superimposition of the distributions corresponding to the particle core and effective anisotropy energies. The method is applied to a ferrofluid composed of non-interacting Fe(3-x)O(4) particles of 4.9?nm average size and x about 0.07. Even though the size distribution is quite narrow in this system, a relatively small value of the effective surface anisotropy constant K(s) = 2.9 × 10(-2)?erg?cm(-2) gives rise to a dramatic broadening of the total energy distribution. The reliability of the average value of the effective anisotropy constant, deduced from magnetic relaxation data, is verified by comparing it to that obtained from the analysis of the shift of the ac susceptibility peaks as a function of the frequency.     

Sampling and quantitative analysis of clean B. subtilis spores at sub-monolayer coverage by reflectance fourier transform infrared microscopy using gold-coated filter substrates

A study was conducted to determine the concentration dependency of the mid-infrared (MIR) absorbance of bacterial spores. A range of concentrations of Bacillus subtilis endospores filtered across gold-coated filter membranes were analyzed by Fourier transform infrared (FT-IR) reflectance microscopy. Calibration curves were derived from the peak absorbances associated with Amide A, Amide I, and Amide II vibrational frequencies by automatic baseline fitting to remove most of the scattering contribution. Linear relationships (R2 >or= 0.99) were observed between the concentrations of spores and the baseline-corrected peak absorbance for each frequency studied. Detection limits for our sampled area of 100 x100 microm2 were determined to be 79, 39, and 184 spores (or 7.92 x 10(5), 3.92 x 10(5), and 1.84 x 10(6) spores/cm2) for the Amide A, Amide I, and Amide II peaks, respectively. Absorbance increased linearly above the scattering baseline with particle surface concentration up to 0.9 monolayer (ML) coverage, with the monolayer density calculated to be approximately 1.17 x 10(8) spores/cm2. Scattering as a function of surface concentration, as estimated from extinction values at wavelengths exhibiting low absorbance, becomes nonlinear at a much lower surface concentration. The apparent scattering cross-section per spore decreased monotonically as concentrations increased toward 1.2 ML, while the absolute scattering decreased between 0.9 ML and 1.2 ML coverage. Calculations suggest that transverse spatial coherence effects are the origin of this nonlinearity, while the onset of nonlinearity in the baseline-corrected absorption is probably due to multiple scattering effects, which appear at a high surface concentration. Absorption cross-sections at peaks of the three bands were measured to be (2.15 +/- 0.05) x 10(-9), (1.48 +/- 0.03) x 10(-9), and (0.805 +/- 0.023) x 10(-9) cm2, respectively. These values are smaller by a factor of 2-4 than expected from the literature. The origin of the reduced cross-section is hypothesized to be an electric field effect related to the surface selection rule.     

Effect of caged fluorescent dye on the electroosmotic mobility in microchannels

We report on measurements of electroosmotic mobility in polymer microchannels and silica capillaries with and without the addition of a caged fluorescein dye to the buffer. For PMMA microchannels, the mobility was found to increase from (2.6 +/- 0.1) x 10(-4) cm2 V(-1) s(-1) to (4.6 +/- 0.1) x 10(-4) cm2 V(-1) s(-1) upon addition of 1.2 mmol/L of caged dye. For PC microchannels, the mobility increased from (4.3 +/- 0.2) x 10(-4) cm2 V(-1) s(-1) to (5.4 +/- 0.1) x 10(-4) cm2 V(-1) s(-1) upon addition of caged dye. For PDMS microchannels, the mobility increased from (4.3 +/- 0.2) x 10(-4) cm2 V(-1) s(-1) to (6.4 +/- 0.5) x 10(-4) cm2 V(-1) s(-1) upon addition of caged dye. For fused-silica capillaries, the mobility ((5.5 +/- 0.2) x 10(-4) cm2 V(-1) s(-1)) was unaffected by the addition of the caged dye.     

Influence of pH and HPC concentration on the synthesis of zinc oxide photocatalyst particle from zinc-dust waste by hydrothermal treatment

This work aimed to use the waste zinc-dust from a hot-dip galvanizing plant for the synthesis of nanosized ZnO photocatalyst powder via hydrothermal treatment. ZnO particles with different morphologies and sizes were obtained by varying the solution pH (8–12) and the amount of hydroxypropyl cellulose (HPC) dispersant (0–0.15% (w/v)) under hydrothermal treatment at 170 °C for 8 h. The influence of the preparation conditions on the properties of resultant ZnO particles were evaluated by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis, laser light scattering and Brunauer–Emmett–Teller analyses. The solution pH affected the crystallinity, particle morphology and specific surface area of the obtained ZnO, which in turn influenced its photocatalytic activity. The addition of the optimum amount of HPC (0.1% (w/v)) in the starting solution acted as a dispersant to reduce ZnO particle agglomeration but had the opposite effect at higher levels. Moreover, ZnO nanorods with various aspect ratios and a diameter and length range of 20–70 nm and 100–400 nm, respectively, were obtained depending on the amount of added HPC. The photocatalytic activity of the synthesized ZnO powder was improved by the addition of the optimal amount of HPC, and correlated to the particle dispersion and specific surface area.     

Sorption potential of rice husk for the removal of 2,4-dichlorophenol from aqueous solutions: kinetic and thermodynamic investigations

The sorption potential of chemically and thermally treated rice husk (RHT) for the removal of 2,4-dichlorophenol (DCP) from aqueous solutions has been investigated. Sorption of DCP by rice husk was observed over a wide pH range of 1-10. The effect of contact time between liquid and solid phases, sorbent dose, pH, concentration of sorbate and temperature on the sorption of DCP onto rice husk has been studied. The pore area and average pore diameter of RHT by BET method are calculated to be 17+/-0.6 m2g-1 and 51.3+/-1.5 nm, respectively. Maximum sorption (98+/-1.2%) was achieved for RHT from 6.1x10(-5) moldm(-3) of sorbate solution using 0.1g of rice husk for 10 min agitation time at pH 6 and 303K, which is comparable to activated carbon commercial (ACC) 96.6+/-1.2%, but significantly higher than chemically treated rice husk (RHCT) 65+/-1.6% and rice husk untreated (RHUT) 41+/-2.3%. The sorption data obtained at optimized conditions was subjected to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherms. Sorption intensity 1/n (0.31+/-0.01) and sorption capacity multilayer C(m) (12.0+/-1.6 mmolg(-1)) have been evaluated using Freundlich sorption isotherm, whereas the values of sorption capacity monolayer Q (0.96+/-0.03 mmolg(-1)) and binding energy, b, (4.5+/-1.0)x10(4)dm(3)mol(-1) have been estimated by Langmuir isotherm. The Langmuir constant, b, was also used to calculate the dimensionless factor, R(L), in the concentration range (0.6-6.1)x10(-4) moldm(-3), suggesting greater sorption at low concentration. D-R sorption isotherm was employed to calculate sorption capacity X(m) (2.5+/-0.07 mmolg(-1)) and sorption energy E (14.7+/-0.13 kJmol(-1)). Lagergren and Morris-Weber equations were employed to study kinetics of sorption process using 0.2g of RHT, 25 cm(3) of 0.61x10(-4)moldm(-3) sorbate concentration at pH 6, giving values of first-order rate constant, k, and rate constant of intraparticle transport, R(id), (0.48+/-0.04 min(-1) and 6.8+/-0.8 nmolg(-1)min(-1/2), respectively) at 0.61x10(-4)moldm(-3) solution concentration of DCP, 0.1g RHT, pH 6 and 2-10min of agitation time. For thermodynamic studies, sorption potential was examined over temperature range 283-323 K by employing 6.1x10(-4)moldm(-3) solution concentration of DCP, 0.1g RHT at pH 6 and 10 min of agitation time and values of DeltaH (-25+/-1 kJmol(-1)), DeltaS (-61+/-4 Jmol(-1)K(-1)) and DeltaG(303K) (-7.1+/-0.09 kJmol(-1)) were computed. The negative values of enthalpy, entropy, and free energy suggest that the sorption is exothermic, stable, and spontaneous in nature.     

Magnetic resonance imaging contrast agent: cRGD-ferric oxide nanometer particle and its role in the diagnosis of tumor

To construct tumor-targeted nanometer particles as a negative magnetic resonance imaging (MRI) contrast agent. Ultra-small superparamagnetic iron oxide (USPIO) nanometer particles were prepared by one-step chemical precipitation. The covalent bond between cyclic RGD (cRGD) containing an Arg-Gly-Asp sequence targeting integrin-alphavbeta3, and USPIO was conducted by chemical crosslinking. The physico-chemical property of cRGD-USPIO was detected. Prussian blue staining was applied to detect the specific binding capacity of cRGD-USPIO and USPIO to human pulmonary adenocarcinoma A549 cells and human umbilical vein endothelial cells. Subsequently, A549 xenografts in nude mice were established, and intravenous injections of USPIO and cRGD-USPIO into the vena caudalis were performed. The enhancement of cRGD-USPIO against tumor MRI signal was evaluated. The mean hydrodynamic diameter of cRGD-USPIO was 43.97 +/- 10.10 nm and the size of the ferric oxide core was 5-10 nm. The specific saturation magnetization was 59.94 A x m2 x Kg(-1). The cell conjugation assay results indicated that the positive staining of the cRGD-USPIO group was significantly enhanced. The in vivo MRI diagnosis indicated that the cRGD-USPIO tumor signal was significantly reduced compared to that of the USPIO group (P < 0.01). The targeted superparamagnetic iron oxide nanometer particle can be a novel MRI negative contrast agent for more specific tumor early diagnosis.     

Nanoparticles of latexes from commercial polystyrene

Nanoparticles of polystyrene (PS) (Mw = 1.0-3.0 x 10(6) g/mol) latexes have been successfully prepared from their respective dilute PS (commercial) solutions in cyclohexane, toluene/methanol, or cyclohexane/toluene at each theta temperature. The cationic surfactant cetyltrimethylammonium bromide (CTAB) was used to stabilize the formed PS latex particles. By varying different concentrations of CTAB and PS solution of various Mw, we have successfully produced, for the first time, stable bluish-transparent latex particles ranging from about 10 to 30 nm in diameter (Dw). The number of polymer chains per latex particle (np) is directly proportional to the volume occupied by each latex particle and hence associated to its Dw. The characteristics of these preformed PS latex particles are quite similar to those obtained from the microemulsion polymerization of styrene as reported in literature. These PS latex particles could be further grown by seeding polymerization of styrene to about 50 nm (Dw) with a monodisperse size distribution of Dw/Dn = 1.08.     

Formation of nanoparticles in flames; measurement by particle mass spectrometry and numerical simulation

The size distributions of nanoparticles in flames are measured using a novel particle mass spectrometer (PMS), which is developed for the size range between 0.3 and 50?nm and for number concentrations between 10(9) and 10(13). Using this instrument the particles are sampled without prior dilution from the flame into a molecular beam. The charged nanoparticles are then deflected by an electric field, to determine the mass according to the time-of-flight principle. The PMS is installed in a low pressure combustion chamber operated at 30?mbar. Measurements are made on primary soot particles and iron oxide particles in a laminar, premixed acetylene/oxygen flame. The soot particles increase in size as a function of the height above the burner and the C/O ratio from 2 up to 10?nm. Iron oxide particles of 3-5?nm are detected as a function of burner height. The soot particles form more rapidly than the iron oxide particles. A model calculation for the formation of silica and iron oxide in hydrogen/oxygen flames is developed, based on previously published reaction mechanisms. On adding a mono-disperse particle coagulation scheme, the time history of the particle number concentration and the particle size is calculated. In agreement with experimental data, the calculations show that iron oxide particles are formed more slowly than silica particles.     

Synthesis of cobalt-based nanocrystal layer in silicon dioxide for nonvolatile memory applications

Cobalt silicide (CoSi) nanocrystal (NC) layer distributed within narrow spatial region is synthesized by thermal annealing of a sandwich structure comprised of a thin cobalt (Co) film sandwiched between two silicon-rich oxide (SiO(x)) layers. It is shown that the size of the CoSi NCs can be controlled by varying the Co film thickness, an increase in the size with increasing thickness. Capacitance-voltage (C-V) measurements on a test metal/oxide/semiconductor (MOS) structure with floating gate based on CoSi NCs of 3.8 nm in diameter and 1.4 x 10(12) cm2 in density are shown to have C-V characteristics suitable for nonvolatile memory applications, including a C-V memory window of about 9.5 V for sweep voltages between -15 V and +8, a retention time >10(8) s, and an endurance > 10(6) program/erase cycles.     

Effect of Iron Particle Size and Concentration on Thermal Conductivity of Iron/Polystyrene Composites

The present study deals with the thermal conductivity of iron/polystyrene (PS) composites containing iron particles of different sizes: (5, 50, 150, and 250)  $\upmu \mathrm{m}$ , and with different iron concentrations: (0, 5, 10, 20 and 30) mass%. The effects of iron particle size and concentration on the thermal conductivity of iron/PS composites are investigated in the temperature range: (30 to 120)  $^{\circ }\mathrm{C}$ . It was found that the addition of ultrafine iron particles enhances the thermal conductivity of the composites more than that of larger (coarser) particles. The thermal conductivity also increases with increasing temperature and iron concentration. The glass transition temperature was found to increase with decreasing size of iron particles. A correlation between the observed electrical and thermal conductivities of the iron composites as a function of iron particle size is presented. Fitting of some theoretical models results in predictions of smaller values of the thermal conductivity than are the experimental values.     

Beryllium colorimetric detection for high speed monitoring of laboratory environments

The health consequences of beryllium (Be2+) exposure can be severe. Beryllium is responsible for a debilitating and potentially fatal lung disease, chronic beryllium disease (CBD) resulting from inhalation of beryllium particles. The US Code of Federal Register (CFR), 10 CFR 850, has established a limit of 0.2 microg beryllium/100 cm(2) as the maximum amount of beryllium allowable on surfaces to be released from beryllium work areas in Department of Energy (DOE) facilities. The analytical technique described herein reduces the time and cost of detecting beryllium on laboratory working surfaces substantially. The technique provides a positive colorimetric response to the presence of beryllium on a 30.5 cm x 30.5 cm (1 ft(2)) surface at a minimum detection of 0.2 microg/100 cm(2). The method has been validated to provide positive results for beryllium in the presence of excess iron, calcium, magnesium, copper, nickel, chromium and lead at concentrations 100 times that of beryllium and aluminum and uranium (UO2(2+)) at lesser concentrations. The colorimetric detection technique has also been validated to effectively detect solid forms of beryllium including Be(OH)2, BeCl2, BeSO4, beryllium metal and BeO.     

Direct deposition of patterned nanocrystalline CVD diamond using an electrostatic self-assembly method with nanodiamond particles

Micron-sized and precise patterns of nanocrystalline CVD diamond were fabricated successfully on substrates using dispersed nanodiamond particles, charge connection by electrostatic self-assembly, and photolithography processes. Nanodiamond particles which had been dispersed using an attritional milling system were attached electrostatically on substrates as nuclei for diamond growth. In this milling process, poly sodium 4-styrene sulfonate (PSS) was added as an anionic dispersion agent to produce the PSS/nanodiamond conjugates. Ultra dispersed nanodiamond particles with a ζ-potential and average particle size of - 60.5 mV and ～ 15 nm, respectively, were obtained after this milling process. These PSS/nanodiamond conjugates were attached electrostatically to a cationic polyethyleneimine (PEI) coated surface on to which a photoresist had been patterned in an aqueous solution of the PSS/nanodiamond conjugated suspension. A selectively seeded area was formed successfully using the above process. A hot filament chemical vapor deposition system was used to synthesize the nanocrystalline CVD diamond on the seeded area. Micron-sized, thin and precise nanocrystalline CVD diamond patterns with a high nucleation density (3.8 ± 0.4 × 10(11) cm(-2)) and smooth surface were consequently fabricated.     

Experience in long-term neutron dose equivalent measurements using etched track detectors with (n,alpha) converters in moderators

Etched track Makrofol detectors combined with Kodak BN-1 boron (n,alpha) converters were used inside a 30 cm diameter polyethylene (PE) sphere for the measurement of the neutron ambient dose equivalent. We found unexpectedly high values for the neutron dose equivalent of about 250 microSv instead of 25 microSv for 3 months' exposure in the natural environment. Results from such detectors etched in the authors' labortories revealed that the tracks could only be induced by spontaneous particle emission from the converter. This was confirmed by track diameter analysis and additional special etching of deeper detector layers. Eight surface barrier detectors were used simultaneosly for several days to measure the alpha spectra of the converters. The overall count rate in the energy range 2.5-7.5 MeV was 10 alpha particles d(-1) x cm(-2) for most of the converters and about 10 times less than this for some of them. To identify the nuclides responsible for alpha emission within the converters, gamma spectra of converters were measured for 8 days using a highly sensitive low-background gamma spectrometry system The spectra clearly indicated a small contamination (10 +/- 3 mBq) of the converter foils with 225Ra (T(1/2) = 5.7 y) typically originating from 232Th.     

In situ measurements of ion-exchange processes in single polymer particles: laser trapping microspectroscopy and confocal fluorescence microspectroscopy

Ion-exchange processes of a cationic dye (Rhodamine B; RhB) were studied for individual polymer particles (diameter of 16-20 μm) by laser trapping microspectroscopy and confocal fluorescence laser microspectroscopy. The absorbance of RhB at 565 nm adsorbed on a cation-exchange particle increased linearly with the concentration of RhB in the aqueous phase, while it was independent of the particle diameter. Fluorescence intensity profile measurements of RhB along the particle diameter by confocal fluorescence microspectroscopy directly proved that ion exchange took place in the surface layer (～2-μm thickness) of the particle in the initial stage (1 h). Diffusion of RhB in the particle was very slow, and ion exchange proceeded gradually to the inner volume in the order of days. The ion-exchange processes were analyzed on the basis of simulation of the time course of the concentration profile of RhB in the particle, and the diffusion coefficient of RhB was determined to be (2-4) × 10(-11) cm(2)·s(-1).     

Synthesis and dye-sensitized solar cell performance of nanorods/nanoparticles TiO2 from high surface area nanosheet TiO2

High surface area nanosheet TiO2 with mesoporous structure were synthesized by hydrothermal method at 130 degrees C for 12 h. The samples characterized by XRD, SEM, TEM, SAED, and BET surface area. The nanosheet structure was slightly curved and approximately 50-100 nm in width and several nanometers in thickness. The as-synthesized nanosheet TiO2 had average pore diameter about 3-4 nm. The BET surface area and pore volume of the sample were about 642 m(2)/g and 0.774 cm(3)/g, respectively. The nanosheet structure after calcinations were changed into nanorods/nanoparticles composite with anatase TiO2 structure at 300-500 degrees C (10-15 nm in rods diameter and about 5-10 nm in particles diameter). The solar energy conversion efficiency (eta) of the cell using nanorods/nanoparticles TiO2 (from the nanosheet calcined at 450 degrees C for 2 h) with mesoporous structure was about 7.08% with Jsc of 16.35 mA/cm(2), Voc of 0.703 V and ff of 0.627; while eta of the cell using P-25 reached 5.82% with Jsc of 12.74 mA/cm(2), Voc of 0.704 V, and ff of 0.649.