Publications by authors named "Mengye Wang"

21 Publications

  • Page 1 of 1

A Rapid and Robust Light-and-Solution-Triggered In Situ Crafting of Organic Passivating Membrane over Metal Halide Perovskites for Markedly Improved Stability and Photocatalysis.

Nano Lett 2021 Feb 11;21(4):1643-1650. Epub 2021 Feb 11.

State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials, Sun Yat-Sen University, Guangzhou 510275, China.

Despite intriguing optoelectronic attributes in solar cells, light-emitting diodes, and photocatalysis, the instability of organic-inorganic perovskites poises a grand challenge for long-term applications. Herein, we report a simple yet robust strategy via light-and-solution treatment to create an organic membrane that effectively passivates CHNHPbI (MAPbI). Specifically, the restructuring of MA is observed on MAPbI in aqueous hydrogen iodide. HIO molecules are generated via the reaction between water and I induced by photocatalysis when MAPbI is illuminated. The hydrogen bonding between HIO molecules at different perovskite particles not only directs the creeplike growth of perovskite particles but also in situ forms a passivating layer firmly anchoring on the perovskite surface with hydrophilic -NH groups tethering to perovskites and hydrophobic -CH moieties exposed to air. Intriguingly, such MA film greatly improves the stability of perovskites against moisture as well as their crystal quality, considerably enhancing the photocatalytic hydrogen evolution rate.
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http://dx.doi.org/10.1021/acs.nanolett.0c04299DOI Listing
February 2021

Hydrogen Impurities in ZnO: Shallow Donors in ZnO Semiconductors and Active Sites for Hydrogenation of Carbon Species.

J Phys Chem Lett 2020 Apr 12;11(7):2402-2407. Epub 2020 Mar 12.

State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials, Sun Yat-sen University, Guangzhou, Guangdong 510275, China.

ZnO, as a low-cost yet significant semiconductor, has been widely used in solar energy conversion and optoelectronic devices. In addition, Cu/ZnO-based catalysts can convert syngas (H, CO, and CO) into methanol. However, the main concern about the intrinsic connection between the physical and chemical properties and the structure of ZnO still remains. In this work, efforts are made to decipher the physical and chemical information encoded into the structure. Through using NMR-IR techniques, we, for the first time, report a new ZnO model with three H cations incorporated into one Zn vacancy. H magic-angle spinning NMR and IR spectra demonstrate that Ga cations are introduced into the Zn vacancies of the ZnO lattice, which replace the H cation, and thus further confirm the feasibility of our proposed model. The exchange between the H cation in Zn vacancies and the D gas phase shows that ZnO can activate H because of the quantized three H cations in the defect site.
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http://dx.doi.org/10.1021/acs.jpclett.0c00509DOI Listing
April 2020

Ti C : An Ideal Co-catalyst?

Angew Chem Int Ed Engl 2020 Jan 3;59(5):1914-1918. Epub 2020 Jan 3.

State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials, Sun Yat-Sen University, Guangzhou, 510275, China.

How 2D Ti C enhances photocatalytic efficiency remains unclear. Now, it is shown that it is graphene quantum dots (GQDs) derived from Ti C , rather than 2D Ti C itself, that play the role of co-catalyst for La Ti O /Ti C (LTC) composites during the photocatalytic reaction. After modification of Ti C derivatives, the photocatalytic efficiency of La Ti O is enhanced 16 times over pure La Ti O . Solid-state NMR, Raman, and HRTEM results confirm the existence of GQDs in Ti C and LTC composites. The GQDs are formed during the chemical change from Ti AlC to Ti C via HF etching, as Ti atoms are removed and unsaturated carbon bonds are left, which react with each other to form sp π-conjugation GQDs. 2D Ti C is completely oxidized to CO modified TiO species, causing Ti C to lose its electrical conductivity and the role as co-catalyst. GQDs largely suppress the photogenerated charge recombination of La Ti O , as revealed by the photoluminescence (PL) and transient photocurrent.
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http://dx.doi.org/10.1002/anie.201913095DOI Listing
January 2020

A mechanism of timing variability underlying the association between the mean and SD of asynchrony.

Hum Mov Sci 2019 Oct 18;67:102500. Epub 2019 Jul 18.

Department of Psychology, Sun Yat-Sen University, China. Electronic address:

Sensorimotor timing behaviors typically exhibit an elusive phenomenon known as the negative asynchrony. When synchronizing movements (e.g. finger taps) with an external sequence (e.g. a metronome), people's taps precede event onsets by a few tens of milliseconds. We recently reported that asynchrony is less negative in participants with lower asynchrony variability. This indicates an association between negative asynchrony and variability of timing. Here, in 24 metronome-synchronization data sets, we modeled asynchrony series using a sensorimotor synchronization model that accounts for serial dependence of asynchronies. The results showed that the modeling well captured the negative correlation between the mean and SD of asynchrony. The finding suggests that serial dependence in asynchronies is an essential mechanism of timing variability underlying the association between the mean and SD of asynchrony.
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http://dx.doi.org/10.1016/j.humov.2019.102500DOI Listing
October 2019

Enabling PIEZOpotential in PIEZOelectric Semiconductors for Enhanced Catalytic Activities.

Angew Chem Int Ed Engl 2019 Jun 26;58(23):7526-7536. Epub 2019 Mar 26.

School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.

The past several decades have witnessed significant advances in the synthesis and applications of PIEZOelectric semiconductors, an important class of materials, including piezoelectric, pyroelectric, and ferroelectric semiconductors. The intriguing combination of physical and chemical phenomena in PIEZOelectric semiconductors has triggered much interest in PIEZOcatalysis, that is, catalysis enabled by PIEZOpotential (i.e., piezopotential, pyropotential, and ferropotential)-induced built-in electric fields, which is the focus of this Minireview. First, the PIEZOelectric materials are briefly introduced. Second, recent developments in PIEZOcatalysis are highlighted, including the introduction of representative PIEZOelectric semiconductors, their possible catalytic mechanisms, novel techniques to produce their PIEZOelectric effects during the catalytic process, and several examples of PIEZOcatalysis. Finally, the challenges in the field and exciting opportunities to further improve the PIEZOcatalytic efficiency are discussed.
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http://dx.doi.org/10.1002/anie.201811709DOI Listing
June 2019

Tapping ahead of time: its association with timing variability.

Psychol Res 2020 Mar 28;84(2):343-351. Epub 2018 Jun 28.

Department of Psychology, Sun Yat-Sen University, Higher Education Mega Center, 132 Waihuan East road, Guangzhou, 510006, Guangdong, China.

Researchers have puzzled over the phenomenon in sensorimotor timing that people tend to tap ahead of time. When synchronizing movements (e.g., finger taps) with an external sequence (e.g., a metronome), humans typically tap tens of milliseconds before event onsets, producing the elusive negative asynchrony. Here, we present 24 metronome-tapping data sets from 8 experiments with different experimental settings, showing that less negative asynchrony is associated with lower tapping variability. Further analyses reveal that this negative mean-SD correlation of asynchrony is likely to be observed for sequence types appropriate for synchronization, as indicated by the statistically negative lag 1 autocorrelation of inter-response intervals. The reported findings indicate an association between negative asynchrony and timing variability.
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http://dx.doi.org/10.1007/s00426-018-1043-2DOI Listing
March 2020

Preparation and Extraordinary Room-Temperature CO Sensing Capabilities of Pd-SnO₂ Composite Nanoceramics.

J Nanosci Nanotechnol 2018 Jun;18(6):4176-4181

Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan, Hubei 430072, China.

Pd-SnO2 composite nanoceramics have been prepared from SnO2 and Pd nanoparticles through traditional pressing and sintering. Their responses to CO at room temperature are found to depend greatly on the content of Pd. For those samples with 1.0 and 5.0 mol% Pd, their resistance increases dramatically upon being exposed to CO in air; while for samples of 0.2 mol% Pd, their resistance decreases greatly upon being exposed to CO in air, and extraordinary room-temperature CO sensing capabilities, including high sensitivities around 15, short response time of 20 s and recovery time of 60 s for 100 ppm CO in air, a high selectivity against H2, have been observed for them. X-ray photoelectron spectroscopy analyses showed that Pd2+ was formed in samples of 1 mol% Pd, while both Pd2+ and Pd4+ were formed in samples of 0.2 mol% Pd. It is proposed that for Pd-SnO2 composite nanoceramics, Pd2+ is responsible for CO-induced increase while Pd4+ is responsible for CO-induced decrease in resistance.
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http://dx.doi.org/10.1166/jnn.2018.15033DOI Listing
June 2018

Graphene-Draped Semiconductors for Enhanced Photocorrosion Resistance and Photocatalytic Properties.

J Am Chem Soc 2017 03 9;139(11):4144-4151. Epub 2017 Mar 9.

Department of Applied Physics and ‡Institute of Textiles & Clothing, The Hong Kong Polytechnic University , Hung Hom, Kowloon, Hong Kong, People's Republic of China.

Semiconductor photocatalysts have been widely used for photochemical water splitting, purification of organic contaminants, and bacterial detoxification. However, most photocatalysts suffer greatly from photocorrosion under visible-light irradiation. Here we report a viable strategy to markedly improve photocorrosion resistance of photocatalysts by draping ultrathin yet highly impermeable graphene layers over a semiconductor CdS electrode. Remarkably, the average lifetime of three-layer-graphene-draped CdS photocatalyst is prolonged by 8 times compared to the as-prepared CdS counterpart without graphene draping. The introduction of graphene layers largely suppresses the charge carrier recombination of the CdS film and decreases the carrier transfer resistance at the graphene-draped CdS electrode/electrolyte interface, as revealed by the photoluminescence (PL) and electrochemical impedance spectroscopy studies, respectively, thereby leading to increased photocurrent and enhanced photocatalytic performance (i.e., a 2.5-fold increase in comparison to that in as-prepared CdS case). Our density functional theory calculations also show that electrons are readily transferred from CdS to graphene, correlating well with the PL measurement. The photocorrosion is mainly caused by oxidation reaction between CdS and O and HO assisted with photogenerated holes, evidenced by X-ray photoelectron spectroscopy characterization. The draped graphene effectively prevents the direct contact between the CdS film and O and HO, thus considerably retarding the photocorrosion of CdS upon visible-light exposure. This simple yet robust graphene-draping strategy for antiphotocorrosion of semiconductor photocatalysts is environmentally friendly as it prevents them from entering into the surrounding environment, thus eliminating the possible secondary pollution.
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http://dx.doi.org/10.1021/jacs.7b00341DOI Listing
March 2017

Plasmon-Mediated Solar Energy Conversion via Photocatalysis in Noble Metal/Semiconductor Composites.

Adv Sci (Weinh) 2016 06 9;3(6):1600024. Epub 2016 Apr 9.

School of Materials Science and Engineering Georgia Institute of Technology Atlanta GA 30332 USA.

Plasmonics has remained a prominent and growing field over the past several decades. The coupling of various chemical and photo phenomenon has sparked considerable interest in plasmon-mediated photocatalysis. Given plasmonic photocatalysis has only been developed for a relatively short period, considerable progress has been made in improving the absorption across the full solar spectrum and the efficiency of photo-generated charge carrier separation. With recent advances in fundamental (i.e., mechanisms) and experimental studies (i.e., the influence of size, geometry, surrounding dielectric field, etc.) on plasmon-mediated photocatalysis, the rational design and synthesis of metal/semiconductor hybrid nanostructure photocatalysts has been realized. This review seeks to highlight the recent impressive developments in plasmon-mediated photocatalytic mechanisms (i.e., Schottky junction, direct electron transfer, enhanced local electric field, plasmon resonant energy transfer, and scattering and heating effects), summarize a set of factors (i.e., size, geometry, dielectric environment, loading amount and composition of plasmonic metal, and nanostructure and properties of semiconductors) that largely affect plasmonic photocatalysis, and finally conclude with a perspective on future directions within this rich field of research.
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http://dx.doi.org/10.1002/advs.201600024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5074328PMC
June 2016

An external template-free route to uniform semiconducting hollow mesospheres and their use in photocatalysis.

Nanoscale 2015 Aug;7(30):12990-7

College of Science, Minzu University of China, Beijing 100081, China.

Solid amorphous TiO2 mesospheres were synthesized by controlled hydrolysis of Ti-containing precursors. Subsequently, solid TiO2 mesospheres were exploited as scaffolds and subjected to a one-step external template-free hydrothermal treatment, yielding intriguing hollow anatase TiO2 mesospheres. The synthetic protocol was optimized by investigating the effect of buffer reagents and fluoride ions on the formation of hollow TiO2 spheres. The diameter of hollow mesospheres, ranging from 308 to 760 nm, can be readily tailored by varying the precursor concentration. The average thickness of a shell composed of TiO2 nanocrystals was approximately 40 nm with a mean crystal size of 12.4-20.0 nm. Such hollow TiO2 mesospheres possessed a large surface area and were employed in photocatalytic degradation of methylene blue under UV irradiation. Interestingly, the synthetic conditions were found to exert a significant influence on the photocatalytic ability of hollow TiO2 mesospheres. The correlation between the degradation ability of hollow TiO2 mesospheres and the precursor concentration as well as the hydrothermal time was scrutinized. The optimal photocatalytic performance of hollow TiO2 mesospheres was identified.
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http://dx.doi.org/10.1039/c5nr02685gDOI Listing
August 2015

One-dimensional densely aligned perovskite-decorated semiconductor heterojunctions with enhanced photocatalytic activity.

Small 2015 Mar 31;11(12):1436-42. Epub 2014 Oct 31.

State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China; School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.

By using one-dimensional rutile TiO(2) nanorod arrays as the structure-directing scaffold as well as the TiO(2) source to two consecutive hydrothermal reactions, densely aligned SrTiO(3) -modified rutile TiO(2) heterojunction photocatalysts are crafted for the first time. The first hydrothermal processing yielded nanostructured rutile TiO(2) with the hollow openings on the top of nanorods (i.e., partially etched rutile TiO(2) nanorod arrays; denoted PE-TNRAs). The subsequent second hydrothermal treatment in the presence of Sr(2+) transforms the surface of partially etched rutile TiO(2) nanorods into SrTiO(3) nanoparticles via the concurrent dissolution of TiO(2) and precipitation of SrTiO(3) while retaining the cylindrical shape (i.e., forming SrTiO(3) -decorated rutile TiO(2) composite nanorods; denoted STO-TNRAs). The structural and composition characterizations substantiate the success in achieving STO-TNRA nanostructures. In comparison to PE-TNRAs, STO-TNRA photocatalysts exhibit higher photocurrents and larger photocatalytic degradation rates of methylene blue (3.21 times over PE-TNRAs) under UV light illumination as a direct consequence of improved charge carrier mobility and enhanced electron/hole separation. Such 1D perovskite-decorated semiconductor nanoarrays are very attractive for optoelectronic applications in photovoltaics, photocatalytic hydrogen production, among other areas.
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http://dx.doi.org/10.1002/smll.201402692DOI Listing
March 2015

Strictly biphasic soft and hard Janus structures: synthesis, properties, and applications.

Angew Chem Int Ed Engl 2014 May 1;53(22):5524-38. Epub 2014 Apr 1.

School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (USA).

Janus structures, named after the ancient two-faced Roman god Janus, comprise two hemistructures (e.g. hemispheres) with different compositions and functionalities. Much research has been carried out over the past few years on Janus structures because of the intriguing properties and promising potential applications of these unusually shaped materials. This Review discusses recent progress made in the synthesis, properties, and applications of strictly biphasic Janus structures possessing symmetrical structures but made of disparate materials. Depending on the chemical compositions, such biphasic structures can be categorized into soft, hard, and hybrid soft/hard Janus structures of different architectures, including spheres, rodlike, disclike, or any other shape. The main synthetic routes to soft, hard, and hybrid soft/hard Janus structures are summarized and their unique properties and applications are introduced. The perspectives for future research and development are also described.
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http://dx.doi.org/10.1002/anie.201309352DOI Listing
May 2014

Optimization of molecular organization and nanoscale morphology for high performance low bandgap polymer solar cells.

Nanoscale 2014 Apr;6(8):3984-94

School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.

Rational design and synthesis of low bandgap (LBG) polymers with judiciously tailored HOMO and LUMO levels have emerged as a viable route to high performance polymer solar cells with power conversion efficiencies (PCEs) exceeding 10%. In addition to engineering the energy-level of LBG polymers, the photovoltaic performance of LBG polymer-based solar cells also relies on the device architecture, in particular the fine morphology of the photoactive layer. The nanoscale interpenetrating networks composed of nanostructured donor and acceptor phases are the key to providing a large donor-acceptor interfacial area for maximizing the exciton dissociation and offering a continuous pathway for charge transport. In this Review Article, we summarize recent strategies for tuning the molecular organization and nanoscale morphology toward an enhanced photovoltaic performance of LBG polymer-based solar cells.
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http://dx.doi.org/10.1039/c3nr06298hDOI Listing
April 2014

Garden-like perovskite superstructures with enhanced photocatalytic activity.

Nanoscale 2014 Apr;6(7):3576-84

State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.

By subjecting amorphous flower-like TiO2 to a facile hydrothermal synthesis in the presence of Sr(2+), garden-like perovskite SrTiO3 superstructures were achieved. The amorphous TiO2 was preformed using ZnO flowers as templates. Different three-dimensional SrTiO3 architectures were coexisted in the garden, including SrTiO3 flowers composed of several hollow sword-shaped petals, many sheet-shaped petals or numerous flake-shaped petals, and SrTiO3 grass consisting of a number of long blades. These SrTiO3 superstructures were simultaneously grown on fluorine-doped tin oxide (FTO) substrates. On the basis of a comprehensive study on the effects of growth time, temperature, initial concentrations of precursor, and pH, the formation of these various hierarchical architectures was attributed primarily to the dissolution of amorphous TiO2 and precipitation of perovskite crystals, followed by the Ostwald ripening process of perovskite nanocrystals and self-organization of perovskite building blocks. Interestingly, this approach can be readily extended to create other perovskite structures, including dendritic BaTiO3 and nest-like CaTiO3, as well as PbTiO3 transformed from plate-like pyrochlore Pb2Ti2O6 after post-thermal treatment. Garden-like SrTiO3 superstructures showed a superior photocatalytic performance when compared to other as-prepared semiconductors and perovskite materials (i.e., ZnO, TiO2, BaTiO3, CaTiO3 and PbTiO3), probably due to their intrinsic photocatalytic activity and special garden-like features with a coexistence of various structures that significantly facilitated the adsorption and diffusion of methyl blue (MB) molecules and oxygen species in the photochemical reaction of MB degradation.
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http://dx.doi.org/10.1039/c3nr05564gDOI Listing
April 2014

Hierarchically structured microspheres for high-efficiency rutile TiO(2)-based dye-sensitized solar cells.

ACS Appl Mater Interfaces 2014 Feb 5;6(4):2893-901. Epub 2014 Feb 5.

State Key Laboratory of Physical Chemistry of Solid Surfaces, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University , Xiamen 361005, China.

Peachlike rutile TiO2 microsphere films were successfully produced on transparent conducting fluorine-doped tin oxide substrate via a facile, one-pot chemical bath route at low temperature (T = 80-85 °C) by introducing polyethylene glycol (PEG) as steric dispersant. The formation of TiO2 microspheres composed of nanoneedles was attributed to the acidic medium for the growth of 1D needle-shaped building blocks where the steric interaction of PEG reduced the aggregation of TiO2 nanoneedles and the Ostwald ripening process. Dye-sensitized solar cells (DSSCs) assembled by employing these complex rutile TiO2 microspheres as photoanodes exhibited a light-to-electricity conversion efficiency of 2.55%. It was further improved to a considerably high efficiency of 5.25% upon a series of post-treatments (i.e., calcination, TiCl4 treatment, and O2 plasma exposure) as a direct consequence of the well-crystallized TiO2 for fast electron transport, the enhanced capacity of dye loading, the effective light scattering, and trapping from microstructures.
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http://dx.doi.org/10.1021/am405442nDOI Listing
February 2014

Ultrasound-assisted synthesis and visible-light-driven photocatalytic activity of Fe-incorporated TiO2 nanotube array photocatalysts.

J Hazard Mater 2012 Jan 15;199-200:410-7. Epub 2011 Nov 15.

Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.

Fe incorporated TiO(2) nanotube arrays (Fe-TiO(2)NTs) were prepared by an ultrasound-assisted impregnating-calcination method. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (DRS) indicated that α-Fe(2)O(3) nanoparticles were deposited into the TiO(2) nanotubes, and in the mean time, some Fe(3+) ions were doped into TiO(2) lattice. The absorption of Fe-TiO(2)NTs in the visible light region increased with the increase of Fe content. The photocatalytic activity of Fe-TiO(2)NTs was evaluated by the degradation of methylene blue aqueous solution under visible light irradiation. The results demonstrated that the Fe-TiO(2)NTs exhibited significantly enhanced photocatalytic activity compared with pure TiO(2)NTs. Photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) analyses further confirmed that the increased photocatalytic activity of the Fe-TiO(2)NTs was attributed to an enhanced separation and transfer of photogenerated charge carriers.
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http://dx.doi.org/10.1016/j.jhazmat.2011.11.031DOI Listing
January 2012

Room temperature one-step synthesis of microarrays of N-doped flower-like anatase TiO2 composed of well-defined multilayer nanoflakes by Ti anodization.

Nanotechnology 2011 Jul 1;22(30):305607. Epub 2011 Jul 1.

Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, People's Republic of China.

Microarrays of N-doped flower-like TiO(2) composed of well-defined multilayer nanoflakes were synthesized at room temperature by electrochemical anodization of Ti in NH(4)F aqueous solution. The TiO(2) flowers were of good anatase crystallinity. The effects of anodizing time, applied voltage and NH(4)F concentration on the flower-like morphology were systematically examined. It was found that the morphologies of the anodized Ti were related to the anodizing time and NH(4)F concentration. The size and density of the TiO(2) flowers could be tuned by changing the applied voltage. The obtained N-doped flower-like TiO(2) microarrays exhibited intense absorption in wavelengths ranging from 320 to 800 nm. Under both UV and visible light irradiation, the photocatalytic activity of the N-doped flower-like TiO(2) microarrays in the oxidation of methyl orange showed a significant increase compared with that of commercial P25 TiO(2) film.
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http://dx.doi.org/10.1088/0957-4484/22/30/305607DOI Listing
July 2011

Analysis of anabolic steroids in hair: time courses in guinea pigs.

Steroids 2009 Sep 3;74(9):773-8. Epub 2009 May 3.

Department of Forensic Toxicology, Institute of Forensic Sciences, Ministry of Justice, Shanghai Key laboratory of Forensic Medicine, Shanghai, PR China.

Sensitive, specific, and reproducible methods for the quantitative determination of eight anabolic steroids in guinea pig hair have been developed using LC/MS/MS and GC/MS/MS. Methyltestosterone, stanozolol, methandienone, nandrolone, trenbolone, boldenone, methenolone and DHEA were administered intraperitoneally in guinea pigs. After the first injection, black hair segments were collected on shaved areas of skin. The analysis of these segments revealed the distribution of anabolic steroids in the guinea pig hair. The major components in hair are the parent anabolic steroids. The time courses of the concentrations of the steroids in hair (except methenolone, which does not deposit in hair) demonstrated that the peak concentrations were reached on days 2-4, except stanozolol, which peaked on day 10 after administration. The concentrations in hair appeared to be related to the physicochemical properties of the drug compound and to the dosage. These studies on the distribution of drugs in the hair shaft and on the time course of their concentration changes provide information relevant to the optimal time and method of collecting hair samples. Such studies also provide basic data that will be useful in the application of hair analysis in the control of doping and in the interpretation of results.
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http://dx.doi.org/10.1016/j.steroids.2009.04.008DOI Listing
September 2009

Physiological concentrations of anabolic steroids in human hair.

Forensic Sci Int 2009 Jan 7;184(1-3):32-6. Epub 2009 Jan 7.

Department of Forensic Toxicology, Institute of Forensic Sciences, Ministry of Justice, Shanghai Key Laboratory of Forensic Medicine, Guangfu Xi Road 1347, Shanghai 200063, PR China.

Doping with endogenous anabolic steroids is one of the most serious issues in sports today. The measurement of anabolic steroid levels in human hair is necessary in order to distinguish between pharmaceutical steroids and natural steroids. This is the first investigation into the physiological concentrations of anabolic steroids in human hair in Chinese subjects. A gas chromatography-tandem mass spectrometry (GC/MS/MS) method was developed for the simultaneous identification and quantitation of five endogenous anabolic steroids (testosterone, epitestosterone, androsterone, etiocholanolone and dehydroepiandrosterone) in hair. After basic hydrolysis, hair samples were extracted with diethyl ether, derivatized and then detected using GC/MS/MS in the multiple-reaction monitoring mode (MRM). The one precursor/two product ion transitions for each anabolic steroid were monitored. The limits of detection for the five endogenous anabolic steroids were in the 0.1-0.2 pg/mg range. All analytes showed good linearity and the extraction recoveries were 74.6-104.5%. Within-day and between-day precisions were less than 20%. This method was applied to the analysis of testosterone, epitestosterone, androsterone, etiocholanolone, and dehydroepiandrosterone in human hair. Full-length hair samples were taken at the skin surface from the vertex of 39 males, 30 females and 11 children from China. None of the subjects were professional athletes. Testosterone and dehydroepiandrosterone were detected in all the hair segments. The physiological concentrations of testosterone were in the range 0.8-24.2 pg/mg, 0.1-16.8 pg/mg and 0.2-11.5 pg/mg in males, females and children, respectively, however, the mean values of dehydroepiandrosterone were much higher than the concentrations of testosterone. These data are suitable reference values and are the basis for the interpretation of results from investigations into the abuse of endogenous anabolic steroids.
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http://dx.doi.org/10.1016/j.forsciint.2008.11.014DOI Listing
January 2009

[Determination of endogenous anabolic steroids in hair using gas chromatography-tandem mass spectrometry].

Se Pu 2008 Jul;26(4):454-9

Institute of Forensic Sciences, Ministry of Justice, Shanghai Key Laboratory of Forensic Medicine, Shanghai 200063, China.

A method of gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed for the simultaneous identification and quantification of five endogenous anabolic steroids (testosterone, epitestosterone, androsterone, etiocholanolone, dehydroepiandrosterone) in hair. After alkaline hydrolysis, the hair sample was extracted with diethyl ether, derivatized with a derivatization reagent (N-methyl-N-trimethylsilyl-trifluoroacetamid/iodotrime-thyisilane/DL-dithiothreitol, 1000:5:5, v/v/w) and detected using GC-MS/MS in the multiple-reaction monitoring mode. The one precursor/two product ion transitions for each anabolic steroids were monitored. The limits of detection for five endogenous anabolic steroids were in the range of 0.1 - 0.2 pg/mg. All analytes showed good linearity and the extraction recoveries were 74.6% - 104.5%. The inter-day and intra-day relative standard deviations (RSD) were less than 17.5%. This method has been applied to the analysis of testosterone, epitestosterone, androsterone, etiocholanolone, dehydroepiandrosterone in 80 Chinese hair samples. These data are the suitable references and the basis for the interpretation of the results from endogenous steroids abuse.
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July 2008

[Determination of endogenous steroids in urine by liquid chromatography-tandem mass spectromretry].

Se Pu 2008 Jan;26(1):10-4

Department of Forensic Medicine, Shanghaii Medical College, Fudan University, Shanghai 200032, China.

A method was developed for the determination of endogenous steroids in urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with methyltestosterone as internal standard. After enzymatic hydrolysis by beta-glucuronidase and liquid-liquid extraction, the urine sample was chromatographed on a Cosmosil C18 column with a mixture of methanol and ammonium acetate-formic acid (68:32, v/v) as mobile phase, then detected using MS/MS system with electrospray ionization (ESI) in multi-reaction monitoring (MRM) mode. The detection limits ranged from 0.01 ng/mL to 10 ng/mL. The recoveries ranged from 96.7% to 106.5%, and the intra- and inter-day precisions (measured as relative standard deviations) were less than 7% and 11%, respectively. With simple and fast sample preparation, the method was sensitive and specific for simultaneous determination of these 5 kinds of endogenous steroids in urine. The method has been successfully applied in pharmacokinetic study and is thus a potential alternative for gas chromatography-mass spectrometry (GC-MS) based procedures in routine analysis of endogenous steroids such as DHEA in human urine.
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January 2008