Structure and mechanism of the formation of core–shell nanoparticles obtained through a one-step gas-phase synthesis by electron beam evaporation

• Andrey V. Nomoev,
• Sergey P. Bardakhanov,
• Makoto Schreiber,
• Dashima G. Bazarova,
• Nikolai A. Romanov,
• Boris B. Baldanov,
• Bair R. Radnaev and
• Viacheslav V. Syzrantsev

Beilstein J. Nanotechnol. 2015, 6, 874–880, doi:10.3762/bjnano.6.89

• likely originated from the starting copper ingot which is known to contain some oxygen. As Si has a higher affinity for oxygen than Cu, oxygen released by the evaporation of the copper or dissolved in the copper would be taken up by the silicon during particle formation. From HRTEM images, it is clear

• electron microscopy (TEM), high-resolution TEM (HRTEM), selective area electron diffraction (SAED), and energy dispersive X-ray fluorescence (EDX) analysis. These measurements were performed on a JEM-2010 TEM (JEOL, Japan, 200 kV accelerating voltage, 0.14 nm resolution) equipped with an EDX (EDAX Co

Transformation of hydrogen titanate nanoribbons to TiO₂ nanoribbons and the influence of the transformation strategies on the photocatalytic performance

• Melita Rutar,
• Nejc Rozman,
• Matej Pregelj,
• Carla Bittencourt,
• Romana Cerc Korošec,
• Andrijana Sever Škapin,
• Aleš Mrzel,
• Srečo D. Škapin and
• Polona Umek

Beilstein J. Nanotechnol. 2015, 6, 831–844, doi:10.3762/bjnano.6.86

•  5A) it is apparent that the hydrothermal conditions are more severe and lead to rougher nanoribbon surfaces. An investigation with high resolution transmission electron microscopy (HRTEM) (Figure 5B) revealed that nanoparticles with a trapezoidal shape were formed on the surfaces of the nanoribbons

Microwave assisted synthesis and characterisation of a zinc oxide/tobacco mosaic virus hybrid material. An active hybrid semiconductor in a field-effect transistor device

• Shawn Sanctis,
• Rudolf C. Hoffmann,
• Sabine Eiben and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2015, 6, 785–791, doi:10.3762/bjnano.6.81

• HRTEM investigations of the as-synthesized particles formed from the precursor solution, which yield stable zinc oxide nanoparticles (Figure 2a). TEM also indicates the successful formation of ZnO nanocrystals in solution after the completion of the microwave irradiation process. Grazing incidence X-ray

• compound. a) HRTEM image of the ZnO nanoparticle obtained from solution and b) GI-XRD spectra of the ZnO thin film after 6 deposition cycles (* = peak intensity arising from the Si/SiO2 substrate). AFM micrographs of (a) the bare wt TMV template immobilized on a Si/SiO2 substrate as well as (b) the wt TMV

Silica micro/nanospheres for theranostics: from bimodal MRI and fluorescent imaging probes to cancer therapy

• Shanka Walia and
• Amitabha Acharya

Beilstein J. Nanotechnol. 2015, 6, 546–558, doi:10.3762/bjnano.6.57

• trimethylammonium bromide (CTAB), butanol and hexane as surfactant, co-surfactant and oil phase, respectively. The silica coating of the Gd2(CO3)3:Tb complex was done by using tetraethylorthosilicate (TEOS) under ammonical conditions. The synthesized NPs were characterized by HRTEM, EDX and FTIR. The size of the

• Gd2(CO3)3:Tb complex was found to be 8–12 nm with high degree of narrow size distribution. The coating with silica was confirmed by HRTEM studies in which the outer material covering the hybrid nanocomposites appeared as a thin layer with diameter of 6 nm. The magnetic properties of the NPs were

• (TMAH). Finally, bioconjugation on silica surface of the magnetic NPs and quantum dots was accomplished by using oleyl-O-poly(ethylene glycol)succinyl-N-hydroxysuccinimidyl ester. The characterization of these NPs was done by using UV–vis and fluorescence spectroscopy, HRTEM, STEM and SQUID studies. The

Palladium nanoparticles anchored to anatase TiO₂ for enhanced surface plasmon resonance-stimulated, visible-light-driven photocatalytic activity

• Kah Hon Leong,
• Hong Ye Chu,
• Shaliza Ibrahim and
• Pichiah Saravanan

Beilstein J. Nanotechnol. 2015, 6, 428–437, doi:10.3762/bjnano.6.43

• field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), BET surface area, UV–vis diffuse reflectance spectra (UV-DRS), Raman and photoluminescence (PL) analyses. The simple and smart synthesis anchored well the deposition

• activity. The HRTEM images (Figure 2d and Figure 2e) further confirm the formation of Pd/TiO2 without changing the original morphology of TiO2. It also further confirms the particles size of palladium. The lattice fringes with spacings of 0.22 and 0.35 nm as seen in Figure 2f can be clearly attributed to

• microscope (HRTEM, JEM-2100F, Jeol) images were obtained at 200 kV. The phase composition of the prepared photocatalysts was analyzed by X-ray diffraction (XRD, Bruker D8 advance X-ray powder diffractometer with Cu Kα radiation λ = 0.154 nm). A micro-PL/Raman spectroscope (Renishaw, inVia Raman Microscope

Tunable white light emission by variation of composition and defects of electrospun Al₂O₃–SiO₂ nanofibers

• Jinyuan Zhou,
• Gengzhi Sun,
• Hao Zhao,
• Xiaojun Pan,
• Zhenxing Zhang,
• Yujun Fu,
• Yanzhe Mao and
• Erqing Xie

Beilstein J. Nanotechnol. 2015, 6, 313–320, doi:10.3762/bjnano.6.29

• results. Additionally, many nanocrystals can be observed in the enlarged TEM image shown in Figure 3b with dimensions from several nm to several tens of nm. The HRTEM image in Figure 3c illustrates that the lattice fringes are well-defined, suggesting that the composite nanowires have a high degree of

• insets are their corresponding enlarged SEM images. (a) Low magnification TEM image of Al4Si6 nanofibers; (b) locally enlarged TEM image; (c) HRTEM image of one area shown in (b); and (d) enlarged TEM image of the fiber surface, the inset is the SAED pattern collected from the fiber’s edge. FTIR spectra

Synthesis of boron nitride nanotubes and their applications

• Saban Kalay,
• Zehra Yilmaz,
• Ozlem Sen,
• Melis Emanet,
• Emine Kazanc and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2015, 6, 84–102, doi:10.3762/bjnano.6.9

Morphology, structural properties and reducibility of size-selected CeO_2−x nanoparticle films

• Maria Chiara Spadaro,
• Sergio D’Addato,
• Gabriele Gasperi,
• Francesco Benedetti,
• Paola Luches,
• Vincenzo Grillo,
• Giovanni Bertoni and
• Sergio Valeri

Beilstein J. Nanotechnol. 2015, 6, 60–67, doi:10.3762/bjnano.6.7

• structure by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The thermal stability of the NPs was investigated by XPS. The aim of this work is to investigate the fundamental relationship between NPs chemical and physical properties, in order to improve the

• deposited’ sample was then annealed at T = 1020 K in UHV. HRTEM experiments were performed by using a JEOL JEM-2200FS instrument working at 200 keV and equipped with a Schottky emitter. The instrument has an objective lens spherical aberration coefficient of 0.5 mm, providing a point-to-point resolution of

• 9 nm (lateral size distribution in the inset) (b) and NPs diameter 14 nm (c). STM images of the non-epitaxial (d) and epitaxial (e) ultra-thin ceria films acquired at 1.5 V and 0.04 nA. STEM (a) and HRTEM (b) images of ceria NPs corresponding to the sample with average diameter of 9 nm, the inset in

Synthesis and characterization of fluorescence-labelled silica core-shell and noble metal-decorated ceria nanoparticles

• Rudolf Herrmann,
• Markus Rennhak and
• Armin Reller

Beilstein J. Nanotechnol. 2014, 5, 2413–2423, doi:10.3762/bjnano.5.251

• size can be determined from TEM images by measuring the diameter of the circumscribed sphere. Up to now we were able to obtain average particle sizes between 39 ± 4 and 260 ± 40 nm. Typical images are shown in Figure 6. The HRTEM image (right) shows that the large particle is indeed composed of 8–10 nm

Hybrid spin-crossover nanostructures

• Carlos M. Quintero,
• Gautier Félix,
• Iurii Suleimanov,
• José Sánchez Costa,
• Gábor Molnár,
• Lionel Salmon,
• William Nicolazzi and
• Azzedine Bousseksou

Beilstein J. Nanotechnol. 2014, 5, 2230–2239, doi:10.3762/bjnano.5.232

• the particles. Adapted with permission from [23], copyright 2014 The Royal Society of Chemistry. Schematic representation of single layer Au@PBA nanoparticles, double layer Au@PBA@PBA core–shell NPs, and hollow PBA NPs. On the right, TEM and HRTEM images of the Au@KNiFe NPs. Adapted with permission

• from [25], copyright 2014 Wiley-VCH. HRTEM images of core–multishell PBA nanoparticles a) RbCoFe@KNiCr@RbCoFe and b) KNiCr@RbCoFe@KNiCr, and c) shows the field-cooled magnetic susceptibility as a function of temperature before and after light irradiation of RbCoFe@KNiCr. Adapted with permission from

Carbon nano-onions (multi-layer fullerenes): chemistry and applications

• Juergen Bartelmess and
• Silvia Giordani

Beilstein J. Nanotechnol. 2014, 5, 1980–1998, doi:10.3762/bjnano.5.207

• -resolution transmission electron microscopy (HRTEM) has been widely employed to visualize CNOs and to study the mechanisms of CNO formation and their structural properties. Raman spectroscopy is another useful technique for the structural characterization of CNOs and corroborates the basic graphitic

• , which corroborated the presence of alkyl groups on the CNO surface. Additional HRTEM and SEM experiments were carried out to further support the successful functionalization and excellent solubility of CNO-C16. The authors also studied the reversibility of this alkylation reaction, which could be

• particles have demonstrated high cellular uptake, low cytotoxicity and lower inflammatory potential than CNTs and a very promising future for biomedical applications. HRTEM images of (a) diamond nanoparticles, (b) spherical carbon onions, and (c) polyhedral carbon onions. Diamond nanoparticles are

Synthesis of Pt nanoparticles and their burrowing into Si due to synergistic effects of ion beam energy losses

• Pravin Kumar,
• Udai Bhan Singh,
• Kedar Mal,
• Sunil Ojha,
• Indra Sulania,
• Dinakar Kanjilal,
• Dinesh Singh and
• Vidya Nand Singh

Beilstein J. Nanotechnol. 2014, 5, 1864–1872, doi:10.3762/bjnano.5.197

• /Sn) from 1 to 10. The irradiated films were characterized using Rutherford backscattering spectroscopy (RBS), atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). A TEM image of a cross section of the

• RBS within a few nm) and this is probably the reason why the Pt edge has a small shift (compared to pristine) in the RBS measurement of the sample. Figure 5c covers the near-surface region of HRTEM analysis which shows that ≈5 nm crystalline NPs are uniformly distributed below the surface. The density

• in Figure 6) upon 50 keV neon ion irradiation, which seems to be responsible for the Pt diffusion, matches well with the NP distribution (obtained from the cross sectional HRTEM analysis) in the film irradiated under the same conditions. Total vacancies produced in the system for a chosen ion–target

Room temperature, ppb-level NO₂ gas sensing of multiple-networked ZnSe nanowire sensors under UV illumination

• Sunghoon Park,
• Soohyun Kim,
• Wan In Lee,
• Kyoung-Kook Kim and
• Chongmu Lee

Beilstein J. Nanotechnol. 2014, 5, 1836–1841, doi:10.3762/bjnano.5.194

• approximately 80 nm. The HRTEM image in Figure 2b confirmed that the core region of the nanowire was perfectly crystalline, whereas the edge region showed twinning along the axis of the nanowire. Fringes with spacings of 0.346 and 0.331 nm corresponding to the interplanar distances of the {100} and {002

The influence of molecular mobility on the properties of networks of gold nanoparticles and organic ligands

• Edwin J. Devid,
• Paulo N. Martinho,
• M. Venkata Kamalakar,
• Úna Prendergast,
• Christian Kübel,
• Tibebe Lemma,
• Jean-François Dayen,
• Tia. E. Keyes,
• Bernard Doudin,
• Mario Ruben and
• Sense Jan van der Molen

Beilstein J. Nanotechnol. 2014, 5, 1664–1674, doi:10.3762/bjnano.5.177

• results of the structural and spectroscopic characterisation of the synthesized 2D ligand-gold nanoparticle arrays (in short Au-NP–S-BPP-arrays), by means of UV-vis and electron microscopy (SEM, HRTEM and 3D TEM) experiments, will be presented. Specifically, surface enhanced Raman spectroscopy (SERS

• -STEM, HRTEM and 3D TEM) are also used to accurately characterise the nanoscale structuring of the multilayered networks on carbon-covered TEM grids. It should be noted that, whereas regular 2D structures are readily obtained on flat (oxidized) silicon substrates, the ordered assembly on the TEM grids

Growth evolution and phase transition from chalcocite to digenite in nanocrystalline copper sulfide: Morphological, optical and electrical properties

• Priscilla Vasthi Quintana-Ramirez,
• Ma. Concepción Arenas-Arrocena,
• José Santos-Cruz,
• Marina Vega-González,
• Omar Martínez-Alvarez,
• Víctor Manuel Castaño-Meneses,
• Laura Susana Acosta-Torres and
• Javier de la Fuente-Hernández

Beilstein J. Nanotechnol. 2014, 5, 1542–1552, doi:10.3762/bjnano.5.166

• strain decreases in the samples shown that the least stress was at 260 °C (−8.26 × 10−5) and the highest was at 230 °C (−2.73 × 10−3). Morphology from TEM and HRTEM TEM images revel that amorphous CuxS from aqueous solution is constituted of nanometric particles with undefined shape that are agglomerated

• phase, from chalcocite to digenite. In order to verify the full transition of the digenite phase an HRTEM analysis of the crystals was made. The distance between the lines in the HRTEM image (Figure 3) is approximately 0.32 nm. This corresponds to the (0015) plane spacing of the digenite phase, which

• predominant phase is the digenite. TEM images of copper sulfide synthesized in organic solution at a) 220, b) 230, c) 240 and d) 260 °C. The morphology of the CuxS change from irregular nanoparticles to nanoprisms with increasing temperature. The encircled area shows an alignment of the nanorrods (b). HRTEM

Probing the electronic transport on the reconstructed Au/Ge(001) surface

• Franciszek Krok,
• Mark R. Kaspers,
• Alexander M. Bernhart,
• Marek Nikiel,
• Benedykt R. Jany,
• Paulina Indyka,
• Mateusz Wojtaszek,
• Rolf Möller and
• Christian A. Bobisch

Beilstein J. Nanotechnol. 2014, 5, 1463–1471, doi:10.3762/bjnano.5.159

• observations show that the excess amount of Au forms clusters of [110]-orientation, in agreement to previous STM studies of the same system by Wang et al. [20]. Also, HRTEM images with atomic resolution show that the Au clusters are crystalline. Apart from that, in Figure 4a, a thin layer exhibiting the

• atomic wires at the surface are not coupled to each other. Our HRTEM data supports this assumption. In Figure 5, an atomically resolved HRTEM image of the interface between the Au cluster and the substrate surface is shown. In image a), on the right side the substrate surface level is indicated by a

• atomic structure of Ge(001) bulk is visible. a) An atomically resolved HRTEM image of the interface between the Au cluster and the surrounding substrate surface. The substrate surface level is indicated with the dashed line. The arrow points to the discontinuity region (“cavity”) between the crystalline

Synthesis, characterization, and growth simulations of Cu–Pt bimetallic nanoclusters

• Subarna Khanal,
• Ana Spitale,
• Nabraj Bhattarai,
• Daniel Bahena,
• J. Jesus Velazquez-Salazar,
• Sergio Mejía-Rosales,
• Marcelo M. Mariscal and
• Miguel José-Yacaman

Beilstein J. Nanotechnol. 2014, 5, 1371–1379, doi:10.3762/bjnano.5.150

• characterized by transmission electron microscope (TEM) and high resolution transmission electron microscopy (HRTEM) by using a JEOL 2010F operated at 200 kV. The STEM images were recorded in a Cs-corrected JEOL JEM-ARM 200F operated at 200 kV. HAADF STEM images were obtained with a convergence angle of 26 mrad

An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals

• Parul Chawla,
• Son Singh and
• Shailesh Narain Sharma

Beilstein J. Nanotechnol. 2014, 5, 1235–1244, doi:10.3762/bjnano.5.137

• characterized by tetragonal morphologies, more agglomeration in the nanocrystals, and lack of the distinct presence of the isolated nanocrystals. The inset in Figure 2a shows a high resolution TEM (HRTEM) image, which demonstrates the presence of crystalline planes with an interplanar spacing d of 0.34 nm

• . Figure 2b shows the TEM micrograph of CIGSe nanocrystals with a size of 100–120 nm and exhibiting a slight improvement in the appearance of the tetragonal morphology, which is characteristic of these chalcopyrites-based nanocrystals. The inset depicts the HRTEM micrograph with well-aligned crystalline

• in terms of crystallinity can be seen due to the emergence of nanocrystals of the size of 150–200 nm. The HRTEM micrograph shown as an inset in Figure 2c depicts the presence of sharp crystalline planes with an interplanar spacing of 0.325 nm. However, a similar trend was observed upon light-soaking

Enhanced photocatalytic hydrogen evolution by combining water soluble graphene with cobalt salts

• Jing Wang,
• Ke Feng,
• Hui-Hui Zhang,
• Bin Chen,
• Zhi-Jun Li,
• Qing-Yuan Meng,
• Li-Ping Zhang,
• Chen-Ho Tung and
• Li-Zhu Wu

Beilstein J. Nanotechnol. 2014, 5, 1167–1174, doi:10.3762/bjnano.5.128

• , in the absence of G-SO3 nanoparticles aggregated in size of about hundreds nanometers. Each particle is composed of lots of small nanoparticles of several nanometers in diameter. The lattice fringes in the HRTEM (high resolution TEM) images suggest a well-defined crystal structure. The lattice

• of the nanoparticles were smaller. The HRTEM image also showed the lattice fringes, and the lattice spacing (0.191 and 0.203 nm) is consistent with those observed in the system without G-SO3. This phenomenon indicated that G-SO3 provides a platform to support cobalt catalysts, and at the same time G

Template-directed synthesis and characterization of microstructured ceramic Ce/ZrO₂@SiO₂ composite tubes

• Jörg J. Schneider and
• Meike Naumann

Beilstein J. Nanotechnol. 2014, 5, 1152–1159, doi:10.3762/bjnano.5.126

• template fibers and the obtained bundles of as-prepared ceramic silica tubes after calcination and removal of the electrospun PS fiber template (750 °C, 4 h). Their tubular structure consists of densely packed agglomerated silica particles (see Figure 1). A high-resolution TEM (HRTEM) study reveals the

• Ce0.12/Zr0.88O2 [11]. Scheme 1 shows the series of synthetic steps which first lead to the PS/silica tubes exotemplate (A) and after sol–gel infiltration to the final CeO2/ZrO2@SiO2 composite tubes (B). An examination of the tube surface composition by HRTEM reveals the spherical Stoeber sol particles of

• has been assumed by HSEM and in HRTEM. Moreover, the intensity of cerium compared to zirconium in the elemental EDX scan is significantly lower, which reflects the phase composition as found by PXRD and Raman spectroscopy. Conclusion A template-directed synthesis was employed for the synthesis of

Organic and inorganic–organic thin film structures by molecular layer deposition: A review

• Pia Sundberg and
• Maarit Karppinen

Beilstein J. Nanotechnol. 2014, 5, 1104–1136, doi:10.3762/bjnano.5.123

Enhancement of photocatalytic H₂ evolution of eosin Y-sensitized reduced graphene oxide through a simple photoreaction

• Weiying Zhang,
• Yuexiang Li,
• Shaoqin Peng and
• Xiang Cai

Beilstein J. Nanotechnol. 2014, 5, 801–811, doi:10.3762/bjnano.5.92

• -resolution TEM (HRTEM) images were taken on a JEOL JEM-2010 (TEM) equipped with an energy dispersive spectrometer (EDS). Electrochemical impedance spectroscopy (EIS) was measured on an IVIUMSTAT electrochemical workstation (Netherlands). The electrochemical experiments were performed in a 3-compartment cell

• ), and HRTEM image of deposited Pt (D). The inset of Figure 9D is the EDS spectrum. Schematic diagram of the reduction of GO by irradiation. Proposed mechanism for the photocatalytic hydrogen evolution of a EY-RGOx/Pt system under visible light irradiation. Peak area ratios of oxygen-containing bonds to

Biomolecule-assisted synthesis of carbon nitride and sulfur-doped carbon nitride heterojunction nanosheets: An efficient heterojunction photocatalyst for photoelectrochemical applications

• Hua Bing Tao,
• Hong Bin Yang,
• Jiazang Chen,
• Jianwei Miao and
• Bin Liu

Beilstein J. Nanotechnol. 2014, 5, 770–777, doi:10.3762/bjnano.5.89

• (HRTEM) analysis as shown in Figure 5b. Furthermore, it can be observed that the dense CN layer intimately connects with the CNS nanosheet to form a heterostructure. The HRTEM image of CN/CNS as shown in Figure 5b clearly distinguishes the phases of CN (the dark region) and CNS (the dim region). The

• lattice spacing for the dark region and the dim region are 0.328 nm and 0.322 nm respectively, which are consistent with the XRD results. The HRTEM image gives solid evidence towards the formation of heterojunction in CN/CNS. Figure 6a shows the photoluminescence (PL) spectra of CN, CNS and a CN/CNS

• heterojunction. (a) FESEM image of CN/CNS heterostructure, (b) XRD and (c) nitrogen adsorption–desorption isotherms and (d) pore size distribution (insert) of CN, CNS and CN/CNS heterostructure. TEM (a) and HRTEM (b) images of a CN/CNS heterostructure. (a) Photoluminescence of CN, CNS and CN/CNS in aqueous

Carbon dioxide hydrogenation to aromatic hydrocarbons by using an iron/iron oxide nanocatalyst

• Hongwang Wang,
• Jim Hodgson,
• Tej B. Shrestha,
• Prem S. Thapa,
• David Moore,
• Xiaorong Wu,
• Myles Ikenberry,
• Deryl L. Troyer,
• Donghai Wang,
• Keith L. Hohn and
• Stefan H. Bossmann

Beilstein J. Nanotechnol. 2014, 5, 760–769, doi:10.3762/bjnano.5.88

• catalyst was reused 10 times. No decrease of the catalytic activity was observed. This observation is based on the consumption efficiency of CO2 from the gas phase and product analysis by GC–MS. Characterization of the catalysts (TEM, HRTEM, XRD, XPS) The TEM image reveals that the newly synthesized Fe

• /Fe3O4 nanoparticles are roughly spherical with a core/shell structure (Figure 2). The mean core diameter is 12 nm, and the shell thickness is 2 nm. HRTEM indicate that each Fe/Fe3O4 nanoparticle assumes polycrystalline structure with rigid edges. TEM images (Figure 3) of recycled catalyst after 10 runs

• of reactions shows that the nanoparticles fused to larger irregularly shaped particles with crystalline substructures on the surface. HRTEM reveal that the substructure is polycrystalline. The XRD patterns of the Fe/Fe3O4 nanoparticles as a function of the number of catalytic runs is shown in Figure

Effects of the preparation method on the structure and the visible-light photocatalytic activity of Ag₂CrO₄

• Difa Xu,
• Shaowen Cao,
• Jinfeng Zhang,
• Bei Cheng and
• Jiaguo Yu

Beilstein J. Nanotechnol. 2014, 5, 658–666, doi:10.3762/bjnano.5.77

• the S-M sample, transmission electron microscopy (TEM) observation is carried out. As shown in Figure 3a, the S-M sample is composed of nanoparticles with an average particle size of about 30 nm. The high-resolution transmission electron microscopy (HRTEM) image in Figure 3b clearly shows the lattice

• observation was carried out by SEM (S4800, Hitachi, Japan) at an accelerating voltage of 5 kV. TEM and HRTEM analysis were conducted by the transmission electron microscopy (JEM-2100F, JEOL, Japan) at an accelerating voltage of 200 kV. The DRS were taken with a UV–vis spectrophotometer (UV2550, Shimadzu

• different methods: (a) microemulsion, (b) precipitation, and (c) hydrothermal. SEM images of Ag2CrO4 samples obtained from different methods: (a) microemulsion, (b) precipitation, and (c) hydrothermal. TEM (a) and HRTEM (b) images of Ag2CrO4 sample prepared by microemulsion method. The inset of (b) is the