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With the increasing importance of power storage devices, demand for the development of supercapacitors possessing both rapid reversible chargeability and high energy density is accelerating. Here we propose a simple process for the room temperature fabrication of pseudocapacitor electrodes consisting of a faradaic redox reaction layer on a metallic electrode with an enhanced surface area. As a model metallic electrode, an Au foil was irradiated with Ar

Novel glass-ceramic composites with optical bandgap tunability were synthesised. Zinc silicate powder (ZS) was mixed with multi-walled carbon nanotubes (MWCNTs) at various mass fractions (0, 1, 2, and 3 wt %), followed by argon sintering. X-ray diffraction (XRD) analysis revealed the structural change from an amorphous ZS phase to a crystalline willemite phase (Zn2SiO4) by adding MWCNTs, and the largest crystallite size was obtained for ZS with 2.0 wt% MWCNTs. Although the agglomeration of ZS and MWCNTs was observed by field emission scanning electron microscopy (FESEM), there was no chemical interaction between ZS and MWCNTs as confirmed by Fourier transform infrared spectroscopy (FTIR). MWCNTs enhanced the crystallisation, which led to the green emission of Zn2SiO4 blue-shifting from 572 nm to 557 nm. The narrowed optical bandgap of Zn2SiO4 was attributed to the MWCNT-induced exciton localised between the valence band and conduction band of Zn2SiO4. The bandgap tuning effect of MWCNTs potentially paved new ways to mass fabricate zinc silicate-based semiconductors with desirable optical bandgap energy Eg, which significantly benefits the sensor and laser-related industry.

This paper presents the modelling of the specific heat capacity (SHC) of CuO/water nanofluids using a support vector regression (SVR) and artificial neural network models (ANN). The models presented were developed from the experimental data of SCH of CuO nanoparticles, the volume fractions of CuO nanoparticles and fluid temperature. The volume fraction of CuO nanoparticles considered ranges from 0.4 to 2% while the temperature range includes 293–338 K. The results obtained revealed that the SVR model exhibits slightly higher accuracy compared to the ANN model. However, both the SVR and ANN models clearly demonstrate better prediction performance for the SHC of CuO/water nanofluids compared to the existing theoretical models. The results obtained in this study proves that machine learning models provide a more accurate estimation of SHC of CuO/water nanofluids and they are recommended for heat transfer calculations due to their superior accuracy.

Eu3+-doped Zn2SiO4/ZnO phosphor-based composites were prepared using a simple thermal treatment method. The effect of Eu3+ content on the morphological and photoluminescence performance was examined using XRD, FTIR, FESEM, UV–Vis, and PL measurement. The existence of two crystal phases by the XRD measurement confirmed the development of zincite (ZnO) and zinc silicate (Zn2SiO4) crystal phases. Besides, the FTIR spectra and FESEM micrograph support the XRD result by verifying ZnO and Zn2SiO4 phase formation through the existence of their characteristic Zn–O–Si and Zn–O vibration modes with the decrement of SiO4 broad absorption band as the Eu3+ concentration increased. Also, UV–Vis absorption spectra presented by the composite samples displayed a broad absorbance that confirmed the addition of Eu3+ ions in the ZnO/Zn2SiO4 has caused the absorption edge of the curve having red shift. The photoluminescence spectrum showed red shift light emissions at 485 and 615 nm, associating with the Zn2SiO4 crystal phase, in addition to the ZnO crystal phase. From the interesting results achieved, this ZnO/Zn2SiO4 phosphor-based composite material can be a potent candidate in optoelectronic applications.

In this work, the potential of utilizing a waste latex-based precursor (i.e., natural rubber glove (NRG)) as a carbon source for carbon nanotube (CNT) fabrication via chemical vapor deposition has been demonstrated. Gas chromatography-mass spectroscopy (GC-MS) analysis reveals that the separation of the lightweight hydrocarbon chain from the heavier long chain differs in hydrocarbon contents in the NRG fraction (NRG-L). Both solid NRG (NRG-S) and NRG-L samples contain &gt, 63% carbon, &lt, 0.6% sulfur and &lt, 0.08% nitrogen content, respectively, as per carbon-nitrogen-sulfur (CNS) analysis. Growth of CNTs on the samples was confirmed by Raman spectra, SEM and TEM images, whereby it was shown that NRG-S is better than NRG-L in terms of synthesized CNTs yield percentage with similar quality. The optimum vaporization and reaction temperatures were 350 and 800 °C, respectively, considering the balance of good yield percentage (26.7%) and quality of CNTs (ID/IG = 0.84 ± 0.08, diameter ≈ 122 nm) produced. Thus, utilization of waste NRG as a candidate for carbon feedstock to produce value-added CNTs products could be a significant approach for eco-technology.

Willemite is an inorganic semiconductor material used for optoelectronic applications. The present study purposes a new polymer thermal treatment method involving calcination temperature to fabricate the willemite nanoparticles. The effects of polyvinylpyrrolidone (PVP) on the structural and optical properties of the material were thoroughly investigated. Thermogravimetric and its derivative confirmed the decomposition behavior of PVP. The minimum calcination temperature to decompose PVP was appraised at 740 °C. The FTIR and the Raman analyses confirmed the presence of organic source before the calcination process and the formation of the crystalline structure of the willemite nanoparticles after the heat treatment. The optimum PVP concentration in this study based on the FTIR results was found to be 40 g L−1. This is the minimum concentration at which the willemite nanoparticles remained pure with homogenous distribution. X-ray diffraction analysis of the PVP samples before calcination was confirmed to be amorphous, and upon calcination between 800 and 1000 °C, an α-willemite phase was obtained. The morphology and the average particle size were determined with FESEM and HR-TEM analysis. The average particle size is between 23.8 and 36.7 nm. The optical energy band was found to be increasing from 5.24 to 5.32 eV with the corresponding increase in PVP concentration from 20 to 50 g L−1. The findings in this study provides a new pathway to understand the effects of PVP concentrations on the structural and optical properties of willemite semiconductor nanoparticles as it may have key potential applications for future optoelectronic devices. The primary task of polyvinylpyrrolidone (PVP) is to serve as a capping agent and to stabilize the metallic salts. The interaction between the PVP and the metallic salts (zinc acetate dihydrate and silicon tetraacetate) is through the strong ionic bonds between the metallic ions and the amide group via oxygen in the PVP chain. The PVP stabilizes the dissolved metallic precursor by amide group steric and electrostatic stabilization. In the drying process at the temperature about 80 °C, the PVP decompose to the shorter polymer chains which they cap the metallic ions. In the step of calcination at the range of 900 °C for 1–4 h, the polymer content and unwanted anions are entirely removed and the nucleation of willemite nanoparticles achieved.

In this work, the interaction effect between polyethylene terephthalate (PET) and multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) on the morphology and thermal properties of the nanocomposites have been investigated. PET nanocomposites with the incorporation of 0.1 wt% and 0.5 wt% of MWCNTs and GNPs were prepared by the melt compounding and injection moulding method. The presence of MWCNTs and GNPs in the PET matrix was confirmed by the X-ray diffraction (XRD) technique. MWCNTs and GNPs acted as a nucleating agent which enhanced the crystallization of PET/MWCNT/GNP nanocomposites at both weight percentages. The result obtained from thermogravimetric analysis (TGA) showed that the incorporation of MWCNTs and GNPs into pure PET improved the thermal stability of the nanocomposites. The nanofillers served as efficient heat sinks which prevent thermal degradation of PET. From the fractured cross-section morphology in field emission scanning electron microscope (FESEM), the nanofillers displayed good dispersion in the PET matrix. Better dispersion distribution found in 0.1 wt% PET/MWCNTs/GNPs nanocomposites compared to 0.5 wt% PET/MWCNTs/GNPs nanocomposites which favor less mechanical and physical failures like crack, delamination, and agglomeration.

Natural rubber (NR) glove disposal is not environmentally appropriate and a range of approaches have been suggested to overcome the problem. Herein we indicate a simple method for producing high-value nanotubes from waste NR glove as a partial solution to the environmental problem. The laboratory-based waste NR glove was selected as a carbon precursor. Carbon nanotubes (CNTs) were synthesized using chemical vapor deposition (CVD) method comprising ferrocene over SiO2 substrate, which acted as a catalyst and surface for the carbon conversion process. The growth temperature was varied using 500, 600 and 700°C. The carbon precursor was analyzed using thermogravimetric analysis (TGA) to determine the optimum thermal decomposition of the waste. The CNTs collected after CVD process were analyzed using Raman spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM). Optimization studies to determine the effect of temperature showed that the highest yield of CNTs was produced under a reaction temperature of 700°C (yield % = 5.47%, Raman ID/IG ratio = 0.82). The nanomaterials formed confirmed as CNTs and amorphous carbon under TEM images of the tubular structure of the products with a diameter range of 13 – 16 nm.

The carbon nanostructures (CNS) were successfully grown during the chemical vapour deposition of ethene (C2H4) and hydrogen (H2) over a supported Ni0.362Fe0.64 catalyst. The temperature of the reaction was varied between 400 °C and 700 °C with different ratios of hydrogen and ethene (20/80, 50/50 and 80/20). The increase of the H2 in the reaction gas gives higher deposition yield of carbon where the maximum yield is observed at a mixture of 50/50 of H2 and C2H4 respectively. The results showed that the structures of the carbon formed by the decomposition of ethene were dependent on the reaction temperature and the gas ratio employed. Graphitic nanofibers (GNFs) and multiwall carbon nanotubes (MWCNTs) were produced when the temperature reached 700 °C, while at the lower temperature 600 °C, disordered CNS with encapsulation and some amorphous nanostructures tended to form.

In this study, the authors attempted to propose the very first study on fabrication and characterization of zinc-boro-silicate (ZBS) glass-ceramics derived from the ternary zinc-boro-silicate (ZnO)0.65(B2O3)0.15(RHA)0.2 glass system through a conventional melt-quenching method by incorporating rice husk ash (RHA) as the silica (SiO2) source, followed by a sintering process. Optimization of sintering condition has densified the sintered samples while embedded beta willemite (β-Zn2SiO4) and alpha willemite (α-Zn2SiO4) were proven in X-ray diffraction (XRD) analysis. Field emission scanning electron microscopy (FESEM) has shown the distribution of willemite crystals in rhombohedral shape crystals and successfully form closely-packed grains due to intense crystallization. The photoluminescence (PL) spectra of all sintered ZBS glasses presented various emission peaks at 425, 463, 487, 531, and 643 nm corresponded to violet, blue, green, and red emission, respectively. The correlation between the densification, phase transformation, microstructure, and photoluminescence of Zn2SiO4 glass-ceramic phosphor is discussed in detail.

Hard anodizing has proven to be a helpful surface treatment for aluminium alloy and typically accompanied by the growth of a porous and highly flawed oxide layer. The presence of pores on the oxide surface can be taken as an advantage in improving the surface properties. Fly-ash particles are high in SiO2 and Al2O3 content and can be utilized as inexpensive strengthening particles, which can increase the wear resistance and microhardness of composite material. It was noticed that limited research had been carried out in utilizing fly-ash as reinforcement on composite oxide coating as a wear resistance candidate. Thus, this study focused on reinforcing fly-ash on oxide coating and investigating its tribological performance. The composite oxide coating was grown on AA2017 aluminium alloy through anodizing process. To understand the effect of anodizing time and fly-ash content, the parameters were varied from 5–60 min and 0–50 g/L, respectively. The findings suggested that 60 min of anodizing time provides the highest thickness and surface roughness at 35 µm and 6.5 µm, respectively. Interestingly, composite oxide coating with 50 g/L fly-ash provides the highest coating thickness but has the lowest roughness at 52 μm and 8.2 μm, respectively. The composite oxide coatings are observed to reduce friction only for a limited time, despite their potential in significantly reducing the wear rate. The wear mechanism observed was adhesion, micro-crack, and delamination. The findings of this study are believed to provide insight on the potential of fly-ash to be a reinforcement for wear-reduction materials.

In this work, we utilize Joule heating to convert Pt-embedded amorphous carbon nanofiber (CNF) to multiwall carbon nanotube (CNT) in a transmission electron microscope (TEM). The transformation process of Pt-embedded amorphous CNF to multiwall CNT and nano-soldering process using Pt encapsulated CNT was investigated in TEM in detail. Molten Pt-encapsulated inside CNF and CNT always flowed towards the anode, proving electromigration to be the dominant force over thermal migration. Controllable electromigration of Pt was utilized to connect the Pt-included CNT to another CNT, thus forming a seamlessly welded CNT structure. Further, two separate CNF were brought together to form Y-contact which was transformed into Y-junction CNT structure by controlled electromigration of Pt. Changes in morphology and electrical property during CNT formation and nano-soldering were probed in real time with high resolution TEM. Our method provides a procedure for the position control synthesis of CNT and its nano-soldering which can be an important step for future development of a CNT based nanoelectrical circuit.

We performed single-walled carbon nanotube (SWCNT) growth on flexible stainless-steel foils by applying alcohol catalytic chemical vapor deposition (CVD) using an Ir catalyst with an alumina buffer layer. When the alumina thickness was 90 nm, vertically aligned SWCNTs with a thickness of 4.6 μm were grown. In addition, Raman and transmission electron microscope results showed that the diameters of most SWCNTs were distributed below 1.1 nm. Compared with conventional CVD growth where Si wafers are used as substrates, this method is more cost effective and easier to extend for mass production of small-diameter SWCNTs.

This study focuses on developing a new simple and low cost environmentally friendly synthesis technique for producing α-Zn2SiO4 nanoparticles. To study the crystal growth, nanostructure and optical properties of the nanoparticles, further analysis was conducted using XRD, FESEM, EDX, FTIR, RAMAN, HRTEM, UV–vis and PL spectroscopy. The analysis confirmed the progress of α-Zn2SiO4 with the increase of calcination temperature. Additionally, calcination at higher temperatures improved the crystallinity and revealed a uniform spherical morphology and better nanoparticle distribution. These findings were found to be in good agreement with XRD and FESEM results. The optical absorption spectra showed a reduction of the absorption intensity due to an improved crystallinity. Several broad emission peaks were observed at wavelengths of 423, 447, 484, and 530 nm with the increase in calcination temperature. The findings of this study are anticipated to result in finding a potential application for phosphor materials in optoelectronic applications.

Ceramic matrix composites (CMCs) are well-established composites applied on commercial, laboratory, and even industrial scales, including pottery for decoration, glass–ceramics-based light-emitting diodes (LEDs), commercial cooking utensils, high-temperature laboratory instruments, industrial catalytic reactors, and engine turbine blades. Despite the extensive applications of CMCs, researchers had to deal with their brittleness, low electrical conductivity, and low thermal properties. The use of carbon nanotubes (CNTs) as reinforcement is an effective and efficient method to tailor the ceramic structure at the nanoscale, which provides considerable practicability in the fabrication of highly functional CMC materials. This article provides a comprehensive review of CNTs-reinforced CMC materials (CNTs-CMCs). We critically examined the notable challenges during the synthesis of CNTs-CMCs. Five CNT dispersion processes were elucidated with a comparative study of the established research for the homogeneity distribution in the CMCs and the enhanced properties. We also discussed the effect of densification techniques on the properties of CNTs-CMCs. Additionally, we synopsized the outstanding microstructural and functional properties of CNTs in the CNTs-CMCs, namely stimulated ceramic crystallization, high thermal conductivity, bandgap reduction, and improved mechanical toughness. We also addressed the fundamental insights for the future technological maturation and advancement of CNTs-CMCs.

A technology for converting waste materials to high quality large-area monolayer graphene film can be significant and thereby obtaining high value-added product. Here, we revealed the transformation of waste chicken fat into uniform monolayer graphene film on re-solidified Cu by a low pressure chemical vapor deposition (LPCVD) technique. The evolve gas analyzer-gas chromatography⿿mass spectrometry (EGA-GC⿿MS) analysis of chicken fat oil showed that the free fatty acid in chicken oil decomposed into a short hydrocarbon chains which makes it favorable to use as a carbon precursor for graphene synthesis. Growth of uniform monolayer graphene film on the re-solidified Cu was confirmed by Raman mapping, where 2D to G peak intensity ratio (I2D/IG) is 3.0 at most of the area. Thus, the use of waste from poultry industry as a carbon source instead of commonly used hydrocarbon gas sources for graphene synthesis can be an approach for green nanotechnology.

Synthesis of hexagonal boron nitride (hBN) crystals with a controlled morphology is a major challenge due to various kinetic and thermodynamic factors at the edge. Supplying BN building blocks by heating precursor ammonia borane at a temperature of 90 °C produced triangular crystals, whereas, at higher heating (130 °C), hBN crystals with a hexagonal morphology were observed. The shape of crystals could also be modulated from hexagonal to triangular under a continuous reduced supply of BN building blocks. We attributed these phenomena to a different growth mechanism dependent on the concentration of BN radicals in the growth region. With a low supply of BN building blocks, crystal growth is the edge attachment limited, producing triangles, whereas, under higher concentration of BN building blocks, crystal growth is limited by diffusion producing hexagons. The presence of alternating B and N terminated vertices in hexagonal hBN crystals offers the possibility of hBN/graphene in-plane heterostructure synthes...

The specific heat capacity of nanofluids ( C P n f ) is a fundamental thermophysical property that measures the heat storage capacity of the nanofluids. C P n f is usually determined through experimental measurement. As it is known, experimental procedures are characterised with some complexities, which include, the challenge of preparing stable nanofluids and relatively long periods to conduct experiments. So far, two correlations have been developed to estimate the C P n f . The accuracies of these models are still subject to further improvement for many nanofluid compositions. This study presents a four-input support vector regression (SVR) model hybridized with a Bayesian algorithm to predict the specific heat capacity of metallic oxides/ethylene glycol-based nanofluids. The bayesian algorithm was used to obtain the optimum SVR hyperparameters. 189 experimental data collected from published literature was used for the model development. The proposed model exhibits low average absolute relative deviation (AARD) and a high correlation coefficient (r) of 0.40 and 99.53 %, respectively. In addition, we analysed the accuracies of the existing analytical models on the considered nanofluid compositions. The model based on the thermal equilibrium between the nanoparticles and base fluid (model II) show good agreement with experimental results while the model based on simple mixing rule (model I) overestimated the specific heat capacity of the nanofluids. To further validate the superiority of the proposed technique over the existing analytical models, we compared various statistical errors for the three models. The AARD for the BSVR, model II, and model I are 0.40, 0.82 and 4.97, respectively. This clearly shows that the model developed has much better prediction accuracy than existing models in predicting the specific heat capacity of metallic oxides/ethylene glycol-based nanofluids. We believe the presented model will be important in the design of nanofluid-based applications due to its improved accuracy.

The electrochemical processes in current fuel cell is still relying on high-loading of scarce and expensive precious metals such as Pt as electrocatalysts for device operation which hinder their commercialization Thus, there is a critical need in search of non-precious metal-based electrocatalysts to replace these precious metals. In view of its corrosion resistant advantage and low production cost, non-precious metal oxides have been recognized as the potential candidates for electrocatalysts in fuel cell. In this study, the aim was to develop a stable catalyst based on transition metal oxides using a simple and cheap modified precipitation technique. Three types of transition metal oxides, namely the cobalt oxides, nickel oxides and iron oxides, were synthesized and a systematic study on the physicochemical properties of the materials are carried out using X-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FESEM). It was observed that cobalt oxide was grown as porous hexagonal platelets while iron oxides and nickel oxides were grown as nanosized particles. The role of the microstructural properties of these transition metals in enhancing their catalytic performance is discussed.

NBR is one of the common rubber used in oil and gas sector, automotive sector and gloves manufacturing. Conversion of solid waste Nitrile Butadiene Rubber (NBR) latex sludge into liquid can be done by using fractional distillation method. The solid waste NBR was heat above its decompose temperature to evaporate the polymer in form of vapor and will be condensed by condenser column into liquid form. The decomposed temperature of waste NBR was determined by Thermogravimetric (TGA) analyzer which is at 450 °C. The processed hydrocarbon liquid was characterized by using Carbon Nitrogen Sulphur (CNS) analyzer, and Gas Chromatography Mass Spectroscopy (GCMS) analyzer. Sulfur is the main compound exist in the waste NBR latex sludge which is 0.73670 % as it being added for vulcanization process. The carbon and nitrogen percentage are 0.17419 % and 0.16479 %.

This work focused on the influence of carbon nanotubes (CNT) to the microstructural properties of Zn2SiO4/CNT (ZSO/CNT) composite. CNT was synthesized via alcohol catalytic chemical vapor deposition (ACCVD) using cobalt oxide as catalyst and ethanol as carbon source. Zinc silicate (ZSO) glass was prepared from quenching the melted commercial waste glass bottle with zinc oxide powder. ZSO/CNT-x composites with various CNT concentration (0, 1, 2 and 3 wt%) was prepared through introducing CNT into ZSO glass via dry processing technique followed by sintering process in Argon gas (Ar) environment and atmospheric (atm) environment, respectively. FESEM, XRD and EDS were employed to determine the surface morphology, phase composition and elemental distribution of sintered sample. Crystallite trigonal willemite (Zn2SiO4) phase was observed from argon sintered sample and the crystallite size of willemite phase in ZSO/CNT-3/Ar showed the most reduced lattice strain of 22.85% compared to ZSO/CNT-0/Ar. In contrast, semi-crystalline phase exhibited in atmospheric sintered sample resulted in high lattice strain. It is concluded that dry powder processing and inert gas thermal treatment can be an effective technique in fabricating strain-reduced ceramics/CNT composite without alternating the domain phase. Least internal strain in crystal lattice have potential on enhancing the luminescence properties of phosphor material and lattice thermal conductivity of thermoelectric material.

Here, we demonstrate the synthesis of nitrogen-doped (N-doped) graphene using imidazole and melamine as two different nitrogen containing aromatic rings carbon precursors. Structure of N-doped graphene was investigated at different temperature (800–1020 °C) without changing the precursor quantity. It is observed that higher crystalline N-doped graphene can be obtained from the solid precursors at 1020 °C on Cu foil. X-ray photoelectron spectroscopy (XPS) analysis shows interesting features for the N-doped graphene synthesized from mixture of imidazole and melamine. Overall graphitic nitrogen content is enhanced in the graphene layers using the mixture of precursors, attributing better coordination of carbon and nitrogen atoms on Cu catalyst. Our finding shows that the graphitic and pyridinic nitrogen content in graphene lattice can be tuned by combination of two different nitrogen containing organic molecules.

Herein, we present a direct observation of the formation of graphene from a single copper–carbon nanoneedle (Cu–CNN) during the measurement of current–voltage (I–V) and direct heating via in situ transmission electron microscopy (TEM). Significant structural transformation of Cu–CNN was observed with an applied potential in a two probe system. Under a high current flow between 4.9 μA to 49.0 μA, the Cu nanoparticles melted and evaporated due to Joule heating. The amorphous carbon began crystallizing and transformed into sp2 hybridized hollow graphitic carbon, which was catalyzed by the dispersed Cu nanoparticles. The temperature generated during the current flow was estimated to be 1073 K, as revealed by an in situ TEM heating experiment. The graphene nanoneedle formed exhibited a high current density of 106 A cm−2, which is comparable to Cu in normal interconnect applications. Thus, the graphene nanoneedle formed will be promising for future alternative interconnect materials.

This study demonstrates graphitization directly through the amorphous carbon under the catalysis of a low-melting-point metal, gallium (Ga), by heating in a vacuum heater as well as by Joule heating during in situ transmission electron microscopy (TEM) operation. For the material system of the mixture of Ga nanoparticles (NPs) and amorphous carbon matrix, the graphitization temperature is determined to be about 600 °C for the first time. With increasing the temperature, evaporation and agglomeration of small Ga NPs start to occur together with the graphitization at around the places where Ga NPs would have been located at the surface region. In situ TEM experiment reveals the accelerated increase in electrical conductivity with structural change from amorphous to graphitization. Thus, the combination of the in situ and ex situ TEM observations is believed to be a lead step to understand deeper the graphitization process and provide information in nanoscale.

In this work, manganese (II, III) oxide, (Mn3O4) doped zinc soda lime silica glasses have been synthesized using a conventional melt-quenching process and followed by control heat treatment process. The crystal phase composition and optical properties of α-Zn2SiO4:Mn3O4 based glass-ceramics are comprehensively studied. The physical properties and crystal growth of α-Zn2SiO4 phase were measured by density analysis, linear shrinkage, X-ray diffraction (XRD) and Fourier transform infrared reflection (FTIR) spectroscopy. From the measurement, the average density and linear shrinkage of α-Zn2SiO4:Mn3O4 based glass-ceramics increased with increasing heat treatment temperature. Besides, the presence of Zn–O–Si bands indicates the formation of α-Zn2SiO4 crystal phase and causing the decrement of energy band gap. The photoluminescence spectra of Mn2+ ions exhibit emission transitions of 4T1(G)–6A1(S) and show a prominent green emission colors of α-Zn2SiO4 phase at 524 nm. Keywords: α-Zn2SiO4, Glass-ceramic, Phosphor, Crystal growth, Optical properties

We have demonstrated the fabrication of Si- and Ge-incorporated carbon nanofibers (CNFs) at room temperature. Graphite foil surfaces were irradiated by Ar+ and Ne+ ions with simultaneous Si and Ge supply, and the dependences of the ion-induced composite CNFs surface morphology on the ion species and type of incorporated materials were investigated. The sample surfaces were characterized by various kinds of densely distributed nanostructures, such as conical protrusions, nanoneedles, nanocones, and CNF-tipped cones, depending on the Si and Ge supply rates during ion irradiation. In addition, Ne+ irradiation yielded longer CNFs compared to Ar+-irradiated CNFs. Thus, the nanostructures growth was controllable by adjusting the ion and material species. Surface morphology of ion-induced Ge-incorporated CNFs.

We have studied graphene formation from a single Ag-incorporated carbon nanofiber (CNF) during electron emission using in situ transmission electron microscopy. The formation of graphene from the Ag-incorporated CNF structure was observed under a high current of between 900 nA to 2.03 μA during field and thermal electron emission. Joule heating during the process generated an increased temperature, estimated at approximately 440 K to 1030 K, leading to the transformation of a significant amount of the amorphous carbon surrounding Ag particles to a graphene structure, and to the nearly simultaneous evaporation of Ag particles. This evaporation interrupted the thermal electron emission process, thus leading to a decrease of the emission current to ∼300 nA. Also, graphene stopped forming after the Ag particles had evaporated. In this paper, the effect of Ag particle size on its ability to catalyze the fabrication of high-quality graphene are discussed.