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Development of superior heterogeneous photocatalyst for hydrogen (H2) evolution with promising pollutant degradable capacity is a significant feature but then again thought-provoking for shaping the energy and environmental issues. In this regard, a photocatalytic H2 evolution using nano diamond (ND) semiconducting materials having pollutant degradable capacity for Rhodamine B dye (RhB) has been rarely reported and hence predicted to the sustainable energy. Productive characteristics such good chemical stability, super hardness, nanometer size, biocompatibility and thermal conductivity, ND is a capable and highly valuable powder physical material. Non-uniform and agglomeration dispersion spread of ND in different solvents are the main problems preventing ND from the wide-use in commercial applications. Upon 535 nm solar light excitation, the fabricated ND sample exhibit remarkable photocatalytic H2 production with a HER of about 400 μmol h−1 than pristine ND (197 μmol h−1). Additionally, this H2 generation dramatically enhances the quantum yield, indicating the H2 terminated sites work as electron reservoirs. Precisely, the kinetic constant pseudo-order of FND for photodegradation of RhB was higher as compared with pristine ND. As such, the results show an important step toward tailor-designed and explain the vital role of FND composites for the rational motifs of fruitful photocatalyst with effective pollutant degradable capability for future demand.

The amorphous structural study of silicon carbide nanowires (SiC-NWs) has drawn strenuous attention in recent years due to their worthwhile properties for wide applications, chiefly in optoelectronics. The facile transformation of crystalline SiC-NWs to amorphous defective SiC-NWs is a challenging task for their broad-scale applications. Herein, we report a fantastic strategy (by applying a 5UDH Pelletron accelerator, located at the National Centre for Physics, Islamabad, Pakistan) for Cu ion implantation (fixed at 10 MeV) on the crystalline SiC-NWs to incorporate them into an amorphous structure. For the defects study, various dose rates of Cu+ ion ranging from 5 × 1015 ions/cm2 to 5 × 1016 ions/cm2 were bombarded on SiC-NWs, and a complete transmutation to the amorphous structure of SiC-NWs under a shelling dose of 8 × 1016 ions/cm2 was observed. This work will provide a better avenue for the structural deformation blueprints of the next-generation nanomaterials. Amorphous structural transformation is explained by collision cascade effects phenomena.

This work reports in-situ ion beam induced luminescence (IBIL) of CaF2 crystals using 2-MeV proton excitation. The in-situ IBIL experiments were carried out at pelletron Tandem accelerator at the National Center for Physics, Islamabad, Pakistan. The spectrophotometry UV–Visible analysis revealed that proton beam induced Ca colloids. Their concentration increases with fluence, and the mean size reaches about 10 nm. The IBIL results showed a wide luminescence band extended from 230 to 450 nm and a new band at about 210 nm, attributed to the self-trapped exciton (STE) decay. It was found that the luminescence intensity increases linearly with dose. From the absorption measurements, indicating the colloid formation in CaF2 by proton irradiation, we believe that the latter colloids are responsible for the luminescence improvement during proton beam irradiation.

The present work reports the in-situ ion beam induced luminescence measurements using 2 MeV proton excitation of LiF single crystal with the aim of obtaining a further insight on F-type centers kinetics and its correlation with the self-trapped exciton (STE). It is found that the STE luminescence intensity decreases from the beginning of irradiation. While the dose-dependent evolution of F3+ and F2 centers reveals three kinetic stages: (i) linear increase from the beginning of irradiation up to 10.1 MGy, followed by (ii) monotonic decrease to 18.1 MGy, and (iii) steady state from 18.1 to 26.2 MGy where the luminescence intensity remains constant. The STE luminescence completely extinguished at high dose; 18.1 MGy in our case. Whereas, the F3+ and F2 luminescence persist and remain constant above 18.1 MGy. The latter behavior revealed in the present study can be useful for LiF application in radiation dosimetry and an imaging detector.

Spinel ferrite based nanoparticle material has been at the forefront of contemporary nanotechnology for use in various industrial and biomedical applications. The preparation and characterization o...

The effect of 5 MeV Cu++ ions irradiation on structural and optical properties of Anatase TiO2 nanoparticles (TiO2-NPs) is investigated. For this purpose, TiO2-NPs are irradiated with different Cu++ ions fluences, ranging from 1 × 1015 to 1 × 1016 ions/cm2 at room temperature. XRD results confirm the Ti3O7 phase appear at the dose of 5 × 1015 ions/cm2 and peak intensity of Ti3O7 phase gradually increases with an increase of Cu++ ions irradiation dose. At the dose of 1 × 1016 ions/cm2 TiO2 Anatase phase were transformed to Rutile phase. Same observations are confirmed from Raman spectroscopy. High resolution transmission electron microscopy (HRTEM) reveals that morphology converted into wavy shape and crystal structure detrioted with increase Cu ion irradiation dose to form vacancy loops and interstitial loops. Scanning electron microscopy (SEM) shows that TiO2-NPs have been fused to form a cluster of nanoparticles at high Cu ion beam dose, while bandgap of TiO2-NPs reduces from 3.19 eV to 2.96 eV as a function of Cu++ irradiation fluence. These phase transformations and crystal damage are the responsible for optical bandgap reduction. The mechanism for the currently observed phase transformation of TiO2 and coalescence of TiO2-NPs are discussed in term of thermal spikes model. Keywords: TiO2 nanoparticles, Cu++ irradiation, Rutile phase, Coalescence of NPs, Bandgap engineering

In this work, short carbon fibers were utilized as reinforcing materials to incorporate with C-SiC ceramics. Cf/C-SiC composites containing diverse fiber contents were fabricated by combining compression molding and hot sintering. Mechanical and tribological properties were carefully investigated. The result indicates that 30 vol% fiber content composite shows the highest flexural strength (201.42 MPa) and shear strength (116.68 MPa). The reinforcing mechanisms are summarized as fiber pulling-out, fiber debonding and fiber bridging, as well as crack deflection. Tribological testing reveals that 30% fiber content composite shows the strongest wear resistance (3.95 × 10−6 mm3/N⋅m) and cyclic performances (COF of 0.27 after 50 cycles). The friction mechanisms are divided into abrasive wear, adhesion wear and oxidation wear by different wear stages.

The development of high dielectric loss and magnetic loss for radar absorbing material is a long-term pursuing and under a close scrutiny. Most of the researches have been focused on exploring absorber materials with good absorption performance and at the same time with a good electrical conductivity. To develop a new absorber material will also have significant impacts on boosting the dielectric loss and magnetic loss. Herein, 3D spherical NiCo2S4 (NCS)-based composite has been fabricated via a mild, simple and useful hydrothermal strategy and the electromagnetic wave absorbing properties have been investigated through comparison among NCS, acidified carbon nanotubes (a-CNT)/NCS, reduced graphene oxide (r-GO)/NCS and r-GO/a-CNT/NCS. The experimental results show that the optimal concentration of NiSO4·6H2O to synthesize the composites is 6 M. Furthermore, the frequency bandwidth has been broadened and the maximum absorption peaks have been increased after adding the modified agent. The maximum frequency bandwidth of r-GO/a-CNT/NCS is 5.1 GHz below −5 dB and 2.7 GHz below −10 dB respectively, the maximum absorption peak is −35.8 dB at 8.1 GHz.

To improve the mechanical properties and oxidation resistance of short carbon fiber reinforced silicon carbide matrix composites, carbon nanotubes (CNTs) were grown in-situ on carbon fiber surfaces through continuous CVD, a small amount of phenolic formaldehyde (PF) was added to the matrix to densify the composite and interlock the fiber and the matrix. The CNTs-Cf/PF/SiC composite was fabricated by combining pre-casting and hot-pressing. Microstructural analyses revealed that CNTs were successfully grown on carbon fiber surfaces with entangled structures, while PF presented cobweb-like structure which tightly bonded the fiber and the matrix. Compared with CNTs-Cf/SiC and Cf/SiC, the flexural strength of CNTs-Cf/PF/SiC increased by 15.27% and 51.95%. After heat treatment, the weight loss of CNTs-Cf/PF/SiC reached 21.05%, and 31.9% of flexural strength retained after 15 thermal shock cycles at 1400 °C. These enhanced properties were indicative of its enormous potential to replace traditional Cf/SiC composite.

In this work, a high-performance electrode material has been fabricated by the incorporation of carbon nanotubes (CNTs) and polyaniline (PANI) on a carbon foams (CF) to improve its electrochemical performance. The microstructure and performance of as-prepared material was characterized in detail. Results showed that the resultant material exhibited a high gravimetric capacitance up to 467.1 F g−1, higher energy density of 104. 2 Wh kg−1 and power density of 3000 W kg−1 at a current density 3 A g−1 when the electrochemical doping time of PANI equals to 20 min. Furthermore, it appeared a good cycling stability with capacitance retention of 94.5% after 10000 cycles. The enhanced electrochemical performance can be attributed to the unique carbon nanostructure and synergistic effects of active materials CNTs and PANI. It indicates that this novel CF/CNTs/PANI-20 composite is a promising candidate for electrochemical capacitors.

In this work, reaction bonded silicon carbide (RBSC) brake composites reinforced by chopped carbon fibers (CCFs) were fabricated by pre-liquid dispersion (PLD), low-temperature compression molding (LTCM) and subsequent densification by liquid silicon infiltration (LSI). The effects of the CCF fraction and PLD process on microstructure, phase composition, compression strength, shear strength and tribological performance of the brake composites were evaluated in detail. Our results showed that the distribution of CCF within the brake composites can be improved substantially through the treatment of PLD process, leading to the lowest open porosity of 9.63% and highest buck density of 1.87 g/cm3 comparing to the composites without PLD. Meanwhile, due to the augment of the interfacial area between the CCF and matrix, the as-prepared brake composite with 20 vol% CCF showed a compression strength as high as 157.55 MPa and shear strength of 22.14 MPa. Moreover, after further graphitization, a highly reliable RBSC brake composite with suitable average friction coefficient (0.427) for braking was obtained via the synergistic effects of lubrication of formed graphite and grain-abrasion by SiC grains in spite of a relatively high mass wear rate. These results show that the CCF reinforced RBSC brake composite is a promising candidate for high performance and low-cost friction composite for the application in brake pads.

Single-walled carbon nanotubes (SWCNTs) were prepared by a modified arc discharge furnace using 500 Torr helium as buffer gas at 600 °C. The effect of the catalyst type on the production of SWCNTs ...

Titanium oxide TiO2/epoxy and TiO2 with detonation nano-diamond (DND)/epoxy nanocomposites were prepared by using ultrasonication method. TiO2 and DND particles as reinforcement species and epoxy as matrix were used to produce nanocomposites. The addition of DND particles into TiO2/epoxy composite improved the dielectric and mechanical properties of nanocomposites in significant amount. The dielectric properties of TiO2-DND/epoxy nanocomposite demonstrated increase in permittivity and conductivity after addition of the DND particles. The maximum and minimum reflection losses of TiO2-DND/epoxy nanocomposite for 0.6 and 0.2 wt% DND loading were detected at −14.5 and −1.3 dB, respectively. The flexural and tensile strength of TiO2-DND/epoxy nanocomposites with the addition of 0.4 wt% DNDs were enhanced to 220% and 223%, respectively. Additionally, the energy to break and percent break strain were 3.9 J and 3.86, respectively for 0.4 wt% DND loading in TiO2-DND/epoxy nanocomposite. Therefore, the present work findings claim that DND particles are well suitable to enrich the dispersion of TiO2 nanoparticles in epoxy matrix, which develops a strong load transfer interface between the nanoparticles and epoxy matrix and consequently leads to superior properties.

Expanded graphite embedded with CuO nanospheres coated with carbon (EG/CuO@C) is in-situ prepared by self-combustion and hydrothermal treatment methods The component analysis of the composite is carried out using X-ray diffraction and its morphology and microstructure are characterized using field emission scanning electron microscopy (FESEM) and transmission electron microscope (TEM). The electrochemical performance is examined by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy in 6 M KOH solution as electrolyte. The experimental results revealed that the EG/CuO@C composite remained porous structure, which is beneficial for supercapacitance. The EG/CuO@C exhibits the high specific capacitance of 335 F g −1 and the capacitance retention of 87% after 8000 cycles at the scan rate of 10 mV s −1 . Moreover, the EG/CuO@C composite remains high energy density of 14.03 Wh kg −1 at the power density of 10.1 kW kg −1 .

A biogenic protocol has been adopted for the formulation of zinc ferrite nanoparticles (ZFNPs) using an aqueous extract of Allium cepa (AC) as a reducing agent for the optimization of its properties. The various characterization results from XRD, SEM, DRS, Raman, and VSM clearly showed that the formulated ZFNP was a single phase with crystallite size in the range of 11–15 nm. A spherical morphology was observed for all the samples with particle size in the range of 34–52 nm. All the samples showed a superparamagnetic behavior with reduced saturation magnetization. The ZFNPs prepared were used for self-heating analysis in hyperthermia applications at 180 Oe applied field and 425 Hz. It produced enough heating within the therapeutic temperature to attain the Curie temperature. The ZFNP formulated is auspicious for hyperthermia applications with less side effect owing to their biocompatibility, moderate Curie temperature, and SAR value within the therapeutic range. The formulated nanoparticles have further broadened the horizon of hyperthermia therapeutic applications with an innocuous protocol within 300 s.

Bio-inspired synthesis of iron oxide nanoparticles (FeONPs) has been carried out by eco-friendly, low cost, and facile method using an aqueous extract of Psidium guajava (PG) leaf as a potential reducing agent. The obtained FeONPs were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), and energy-dispersive spectroscopy techniques. The surface plasmon resonance peak of FeONPs was found to be 310 nm. The FTIR spectra analysis indicates the presence of various functional groups in PG extract that are responsible for the biosynthesis of FeONPs. The XRD confirmed that FeONPs were indexed into the cubic spinel lattice structure. The SEM and TEM analysis confirmed the spherical morphology of FeONPs with particle size ranging from 1 to 6 nm. The superparamagnetic nature of the formulated FeONPs was determined using VSM. The FeONPs formulated inhibit the growth of six human pathogenic strains with strong activity chiefly against Escherichia coli and Staphylococcus aureus at low concentration when compared to other standard antibacterial drugs. It is noteworthy that the formulated FeONPs are efficient as an antibacterial agent.

Recently, copper sulfide (CuS) quite arouses researchers' interest due to its high theoretical capacity and excellent electroconductivity. However, poor cycling stability seriously limited the application in supercapacitors. In addition to the improvement of cycling performance, it is also a challenge to develop electrode materials with energy density. Herein, RGO/CuS composite is prepared successfully by solvothermal reaction methods. By the observation using FESEM and TEM, CuS microstructure displays regular and tiny nanoparticles, which are supported by RGO sheets. After the electrochemical measurements, RGO/CuS composite exhibits a maximum specific capacitance of 946 F g−1 at 10 mV s−1 and 906 F g−1 at 1 A g−1, respectively. The excellent cycling stability is also achieved and it maintains 89% retention after 5000 cycles at 5 A g−1. RGO/CuS composite also possesses high energy density of 105.6 W h kg−1 at the power density of 2.5 kW kg−1, which indicates that RGO/CuS composite has a bright future as electrode materials for supercapacitors.

3D printing is a fast-emerging technology, and a shape is fabricated using layer-by-layer deposition of a material in a bottom-up manufacturing operation. Here a porous nickel/polyaniline nanocages multiscale supercapacitor synthesized using 3D printing technology is fabricated. The porous structure of iron-nickel and polyaniline nanocages can increase the specific surface area which lead to enhance the specific capacitance. 3D printing technology is presented in energy devices to accurately fabricate the delicate structure.

Porous copper (Cu) films were facilely and greenly fabricated by low-current electrical field-induced assembly of ~ 3 nm Cu nanoparticles (NPs) in several minutes using generated hydrogen bubbles as dynamic negative templates. The porous films had open three-dimensionally (3D) interconnected nanopores and uniform pore size distribution and exhibited a hierarchical structure composed of supraparticles that were further composed of the Cu NPs. Lattice-to-lattice connectivity in the self-assembly of the NPs in the 3D structures enables fast charge transport. The structure/morphology of the porous Cu materials can be tuned by adjusting the concentration of the additives, applied potential/current densities and assembly time. A growth mechanism of the porous films was reasonably proposed for the field-induced assembly of the Cu NPs. The porous Cu film-supported Si electrode showed high capacity of 1173 mAh g−1 and retention rate of 87% after 10 cycles at 1 C. Our research sheds a light on preparing 3D nanoporous structures especially for suitable electrodes in electrochemical energy storage devices.

High temperature lithium-sulfur batteries are seldom investigated due in part to the lack of mechanical robust separators and the more serious parasitic polysulfide shuttle effects at elevated temperature. Here, we for the first time present high performance lithium-sulfur cells that can be cycled at elevated temperature of 100 °C via designing asymmetric functionalized polyimide-based separators using a facile and scalable blade-casting method. In this sandwich configuration, polyimide nonwovens act as electrochemically and mechanically robust skeleton while Super-P nanoparticles coating and poly (ethylene oxide)-integrated-lithium lanthanum zirconium oxide coating render additional functions of immobilizing polysulfides and inhibiting lithium dendrite growth, respectively. By virtue of the multifarious functions of the modified polyimide-based separator, a high specific capacity of 1474.3 mAh g−1 without severe over-charge behavior is also firstly demonstrated at a higher temperature of 100 °C. Additionally, Li-S cells using the modified polyimide -based separator deliver excellent cycling stability (only 0.2% capacity decay cycle−1 on average exceeding 200 cycles at 80 °C) at a relatively high rate of 5C. The experimental results validate the pivotal role of newly designed separators for high performance lithium-sulfur chemistry especially at elevated temperature.

Recently, ceramic matrix composites reinforced by short carbon fibers (CFs) attracted increasing attentions. To further improve mechanical properties and oxidation resistances, CFs were subjected to oxidation and acidification followed by sol-gel dip-coating to deposit ZrO2 on their surfaces. ZrO2-Cf/SiC composites were fabricated by joint hot compression molding and sintering, compared to Cf/SiC and SiC prepared by the same method. Microstructural analyses indicated that ZrO2 coatings were successfully deposited on CF surfaces, formed strong bonding and interfaces between CF and the matrix. Meanwhile, CFs were found uniformly distributed in SiC matrix with random orientations. Flexural curves of ZrO2-Cf/SiC and Cf/SiC revealed the presence of “false plasticity” regions after sharp drops, which were quite different from brittle flexural behavior of SiC ceramic. Compression strength of the three samples showed step-up growth. ZrO2-Cf/SiC exhibited the highest value, indicating the introduction of CFs and ZrO2 coatings do have great influence on mechanical performances. After heat treatment, ZrO2-Cf/SiC exhibited better oxidation resistance than Cf/SiC, with weight loss ratios estimated to − 3.76% and − 6.43%, respectively. These improved properties indicated that ZrO2-Cf/SiC would be excellent alternatives to other existence materials under ultra-high temperature environments.

Diamond nanoparticles (DNPs) have been strongly integrated into diverse technological applications due to its nano-size, good chemical stability, super hardness, thermal conductivity and biocompatibility. Agglomeration and non-uniform distribution of DNPs in different matrices are the two main concern problems which limits its wide spread applications. Herein, our present research work demonstrated a comparative study of ball milling and acid treatments of functionalization DNPs through surface modification with carboxylic acid and amid functional groups. The dispersion measurement showed that ball mill treated DNPs is uniform and homogeneously dispersed in dimethyl-sulfoxide (DMSO) rather than as-received and acid treated DNPs. Furthermore, the use of various weight percentages of acid and ball mill functionalized DNPs in epoxy resin showed that 0.2 wt% is the optimum amount which revealed the highest ultimate tensile strength, flexural strength, Young's modulus and energy to break values of the nanocomposites. The comparative analysis showed that ball mill treatment of functionalization significantly enhanced the mechanical performances of epoxy resin more effectively than acid treatment thus demonstrated the importance of ball milling technique.

The practical implementation of nanomaterials in high capacity batteries has been hindered by the large mechanical stresses during ion insertion/extraction processes that lead to the loss of physical integrity of the active layers. The challenge of combining the high ion storage capacity with resilience to deformations and efficient charge transport is common for nearly all battery technologies. Layer-by-layer (LBL/LbL) engineered nanocomposites are able to mitigate structural design challenges for materials requiring the combination of contrarian properties. Herein, we show that materials engineering capabilities of LBL augmented by self-organization of nanoparticles (NPs) can be exploited for constructing multiscale composites for high capacity lithium ion anodes that mitigate the contrarian nature of three central parameters most relevant for advanced batteries: large intercalation capacity, high conductance, and robust mechanics. The LBL multilayers were made from three function-determining components...

In this work, a long-life and high-performance electrode material is successfully fabricated by the incorporation of carbon nanotube (CNT) with different length using chemical vapor deposition (CVD) on a hierarchically three dimensional (3D) carbon foam (CF), which is obtained from the mesophase pitch. The morphology, composition, and electrochemical performance of the as-prepared composites are characterized using the scanning electron microscope (SEM), Raman spectroscopy, X-ray diffraction (XRD) patterns, cyclic voltammetry, and galvanostatic charge/discharge cycling techniques. Characterizations suggest that this resultant CF/CNT-50 electrode material has a good cycling stability with capacitance retention of 96.5% even after 10000 cycles. Moreover, it shows a high mass capacitance of 227.5 F/g based on the resultant electrode materials, higher energy density of 28 Wh kg−1 and power density of 3700 W kg−1 at a current density 2 A g−1 and also excellent charge/discharge rate. These measured charge storage properties make the proposed hybrid materials excellent electrode material candidates for high performance supercapacitors.

Mullite whisker 3-D network with controllable size can be obtained via direct sintering from coal gangue and bauxite in lithium chinastone-MnO2-CaCO3 complex catalyst. The unique “bird’s nest”-like structures consist of uniform mullite whiskers with a width of 200 nm and length of up to 3–5 µm, which exhibit excellent flexural strength (165.61 MPa) with a relatively low density (1.55 g cm−3). The sizes and shapes of mullite crystals can be controlled by changing the content of lithium chinastone. The possible formation mechanism of “bird’s nest”-like mullite whisker 3-D network structure was also discussed.

Coiled amorphous carbon nanotube (CACNT) array was prepared by chemical vapor deposition method. The experimental results indicated that the length of as-prepared CACNT array was about 30 μm. The electromagnetic wave absorbing properties were studied through comparison among CACNTs, CACNT-La(NO 3 ) 3 , CACNT-(Fe, Co, Ni) and CACNT-reduced graphene oxide (RGO). The experimental results showed the maximum frequency bandwidth of CACNT-(Fe, Co, Ni) was 6.4 GHz below −5 dB and 2.3 GHz below −10 dB separately. Compared to the pure CACNTs, all the frequency bandwidth had been broaden after adding the modified agent. Meanwhile, the additive of rare earth ions La 3+ could effectively increase the maximum absorption peak (−17.94 dB at 8.96 GHz).

Pt nanoparticles decorated with rose-like Bi2O2CO3 configurations were synthesized via a simple photoreduction method at room temperature. The structure, morphology, optical and electronic properties, and photocatalytic performance of the as-prepared materials were characterized. Compared to pure Bi2O2CO3, the Pt/Bi2O2CO3 photocatalysts show better performance in decomposing RhB, BPA and OTC under visible light (λ > 420 nm). The enhanced photocatalytic activity of Pt/Bi2O2CO3 could be attributed to the modification in light absorption (λ > 420 nm) charge migration and the separation of photo-generated electrons (e−) and holes (h+). Free radical trapping experiments demonstrated that the main active species of the catalytic reaction are different in decomposing RhB and BPA.

C f /Ti 3 SiC 2 -SiC composites with different content of short carbon fibers were fabricated by the combination of compression molding and pressureless sintering. Microstructure and mechanical behavior of the composites were studied to evaluate the comprehensive performance of the material. In comparison, composites without carbon fibers were also fabricated in the same way. The results indicate that Ti 3 SiC 2 phases were synthesized in each cases and exhibit typical laminated structure with smooth surface. With the increase of carbon fiber content, composites turn from brittle to toughness, and show obvious elastic and no-linear regions on the force-displacement curve. Moreover, composite with 30% (volume fraction) carbon fiber shows the highest flexural strength (284.03 MPa), open porosity (15.78%), and lowest density (2.37 g cm −3 ). There were chemical reactions occurred between carbon fibers and matrix which formed strong covalent bonds and interfaces. The micrographs also reveal that fiber bridging and pulling-out are the most important reinforcement mechanisms which contribute to the mechanical properties of the composites.

This work presents a simple approach to produce controlled mullite whisker network structure. Mullite whisker networks were facilely prepared by direct sintering of coal fly ash, bauxite and kaolin in BaCO3-potash feldspar-pyrolusite-talcum catalytic system at 1350 °C. Controlled mullite whiskers were obtained with about 200 nm in diameter and 3 μm in length by controlling the rate of Al2O3 diffusion through feldspar addition in catalytic system. Morphology evolution process and growth characteristics of mullite whisker networks were further investigated using scanning electronic microscope (SEM) and their possible fabrication mechanism were also investigated. The optimum mullite whisker network structural material exhibits some attractive properties such as high strength (199.89 MPa), low density (1.51 g cm−3) and low acid solubility (2.63 wt%). These results demonstrate an effective method to prepare large-scale mullite whisker network with potential applications in producing ceramic proppants.

Amorphous carbon nanotube (ACNT)/sulfur composites were prepared by solution reaction method. The electrochemical results showed that both ACNT/S composite and ACNT/S mixture had a first reversible capacity of 1020 mA h·g −1 , and the capacity retention of ACNT/S composite was 77% after 100 cycles while that of ACNT/S mixture was only 35% with the initial capacity being 850 mA h·g −1 . The experimental results showed that the reversible lithium insertion capacity of the composite was obviously high and the cycling stability was good, which was mainly due to the solid and uniform dispersion of the sulfur and amorphous carbon nanotube matrix in the composite.

Multi wall carbon nanotubes (MWCNTs) and diamond nanoparticles (DNPs) reinforced carbon foam composites were prepared by the direct pyrolysis of MWCNTs, DNPs and mesophase coal tar pitch mixture. The effect of additive amounts on the microstructure and properties of carbon foams were studied. Significant impacts on the microstructure of carbon foams were observed after the incorporation of additive amounts. Whereas, the additive behavior of MWCNTs and DNPs were further investigated in terms of adsorption, mechanical and thermal properties. The results shows that the nickel (Ni) and cadmium (Cd) metal ions adsorption tendency increases with the increase of MWCNTs and DNPs contents. The maximum adsorption percentage of 84.6 and 86.9% was observed for carbon foam containing 2 wt% MWCNT-DNPs loading for Ni and Cd ions respectively. Furthermore, the compressive strength and thermal conductivity of the carbon foams were enhanced with the increase of additives amounts. Maximum improvement of 19.22 MPa in the compressive strength and 37.46 W/m K at 800 °C of thermal conductivity was revealed by carbon foam composite containing 4 wt% MWCNT-DNPs additive amounts.

We applied acid treatment for the surface modification of detonation nanodiamond (DND) powder by minimizing their surface energy to overcome agglomeration and improve dispersion of DNDs. Different concentrations of acid modified DND in 828 epoxy matrix were fabricated to check their mechanical and electromagnetic properties. Mechanical properties were checked in terms of ultimate tensile strength (UTS), toughness, energy to break, percent strain break and Young's modulus while electromagnetic shielding properties were studied in frequency range of 11–17 GHz. To analyze electrical and magnetic properties of the nanocomposites, relative permittivity and permeability tests were performed. Excellent interactions among acid modified DND and epoxy resin was observed due to carboxyl and hydroxyl functional groups that results in the formation of efficient load transfer interface, which in turn enhance the mechanical and electromagnetic properties of epoxy nanocomposites. During investigation it was observed that mechanical properties and relative permittivity showed enhancements when, 0.2 wt% acid modified DND were used as a nano-filler, while on further increment of modified DND these properties start decreasing. Unlike this, the relative permeability, reflection and transmission loss values were increased with the increase of acid modified DND content.

The pursuing aim of high reflection loss and broad frequency bandwidth for electromagnetic wave (EMW) absorbing materials is a long-term task and under a close scrutiny. To construct rational microstructures for the absorber have significant impacts on increasing reflection loss and broadening frequency bandwidth. Herein, we presented a sandwich microstructured expand graphite (EG)/BaFe12O19 (BF) nanocomposite successfully prepared by in-situ sol-gel auto-combustion method. The experimental results showed that EG/BF nanocomposite has better EMW absorbing performance than pure EG and BF, the sandwich microstructured EG/BF connected with carbon nanotubes (CNTs) could further improve the electromagnetic performance effectively. The obtained CNT/EG/BF nanocomposite exhibited a saturation magnetization of 26.5 emu g−1 at room temperature and an excellent EMW absorbing performance. The maximum reflection loss of the sandwich microstructured CNT/EG/BF composites with a thickness of 1 mm was up to −45.8 dB and the frequency bandwidth below −10 dB could reach to 4.2 GHz within the frequency range of 2–18 GHz. The research results indicated that the prepared nanocomposite showed great potential as a new type of microwave absorbing material.

Homogeneous amorphous carbon nanotube (ACNT) networks have been synthesized using floating catalyst chemical vapor deposition method on a 3D graphene aerogel (GA)/ BaFe12O19 (BF) nanocomposite which was prepared by a self-propagating combustion process. The as-synthesized ACNT/GA/BF nanocomposite with 3D network structures could be directly used as a good absorber material for electromagnetic wave absorption. The experimental results indicated that the minimum reflection loss of ACNT/GA/BF composite with a thickness of 2 mm was −18.35 dB at 10.64 GHz in the frequency range of 2–18 GHz. The frequency bandwidth of the reflection loss below −10 dB was 3.32 GHz and below −5 dB was 6.24 GHz, respectively. The 3D graphene aerogel structures which composed of dense interlined tubes and amorphous structure bearing quantities of dihedral angles could consume the incident waves through multiple reflection and scattering inside the 3D web structures. The interlinked ACNTs have both the virtues of amorphous CNTs (multiple reflection inside the wall) and crystalline CNTs (high conductivity), consuming the electromagnetic wave as resistance heat. ACNT/GA/BF composite has a good electromagnetic wave absorption performance.

A novel silicon core/amorphous carbon nanotube (ACNT) shell composite that can be used as lithium-ion batteries anode material was in-situ synthesized in the chemical vapor deposition (CVD) growth process. The hypothesized core/shell structure was evidenced by SEM/TEM/XRD, suggesting that the ACNTs composed of carbon clusters with short-range order and long-range disorder were successfully deposited onto the surface of the silicon particles. This Si/ACNT composite delivered a high capacity of 1496 mAh g −1 at a current density of 100 mA g −1 , and a superior cycling stability with 80% capacity retention after 300 cycles. This observed specific capacity improvement of Si/ACNT composite is likely attributed to the formed three-dimensional conductive networks between silicon particles and interwoven ACNTs in the composite.

In this article, three-dimensional (3D) heterostructured of MnO2/graphene/carbon nanotube (CNT) composites were synthesized by electrochemical deposition (ELD)-electrophoretic deposition (EPD) and subsequently chemical vapour deposition (CVD) methods. MnO2/graphene/CNT composites were directly used as binder-free electrodes to investigate the electrochemical performance. To design a novel electrode material with high specific area and excellent electrochemical property, the Ni foam was chosen as the substrate, which could provide a 3D skeleton extremely enhancing the specific surface area and limiting the huge volume change of the active materials. The experimental results indicated that the specific capacitance of MnO2/graphene/CNT composite was up to 377.1 F g−1 at the scan speed of 200 mV s−1 with a measured energy density of 75.4 Wh kg−1. The 3D hybrid structures also exhibited superior long cycling life with close to 90% specific capacitance retained after 500 cycles.

In this work, reduced graphene oxide (RGO) - carbon nanotubes (CNT) grown on carbon fiber (CF) is fabricated by a combination of electrophoretic deposition (EPD) and chemical vapor deposition (CVD). Firstly, CF-GO composite is prepared via EPD. Secondly, the CF-RGO-CNT hybrid is obtained by floating catalyst chemical vapor deposition method for synthesizing CNT on the CF-RGO substrate. The as-prepared three-dimensional (3D) hierarchical hybrid shows strong mechanical stability and high flexibility at various bending angles. Furthermore, the hybrid is characterized by scanning electron microscope, X-ray Diffraction and Raman spectroscopy, and its supercapacitor properties are also tested. The electrochemical measurements display a higher specific capacitance of 203 F g−1, 4 times higher than that of pure CF. Importantly, the hybrid shows high electrochemical stability at various bending angles, and can be directly served as flexible electrode with binder-free for high-performance supercapacitors. All these attractive results indicate that the as-prepared 3D hybrid is a promising candidate for flexible supercapacitor applications.

Aligned amorphous carbon nanotube (AACNT)/BaFe12O19 nanorod (BNR) composite was prepared by chemical vapor deposition and ball-milling methods. Raman and XRD tests were performed to investigate the microstructures, and the microwave absorbing properties of the as prepared composite were characterized using a vector network analyzer. The experimental results indicated that the mean length of as-prepared ACNT arrays was about 24 μm and the average length of BNRs were about 50 nm. The maximum absorbing peak of AACNTs/BNR composite is −21.5 dB at the frequency of 9.3 GHz. The frequency bandwidth of the reflectivity loss below −10 dB is about 2.5 GHz. AACNTs have both features of amorphous CNTs which have multiple-reflective path inside the tube-wall and crystalline CNTs which have high conductivity.

High strength lightweight mullite whisker network reinforced ceramic materials was successfully prepared by firing a bauxite - kaolin - coal fly ash mixture with additions of varying mixtures of feldspar - talcum - BaCO 3 - pyrolusite. The mullite whisker network exhibits a unique architecture in which thin mullite crystals layers with anisotropic properties and well controlled crystal size were interweaved with one another. The effects of pyrolusite content on morphologies and properties of resultant ceramic materials were investigated. The phase compositions and microstructures of several samples were investigated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The flexural strength and acid solubility of ceramic materials as functions of sintering temperature were systematically investigated by measuring the flexural strength and acid solubility at different sintering temperature, respectively. The resulting mullite whisker network structure ceramic materials showed optimum performance at sintering temperature around 1390 °C when the content of pyrolusite equals to 6 wt%, such as high strength (190.10 MPa), low density (1.48 g cm −3 ) and low acid solubility (2.55 wt%). The approach opens new opportunities for the sintered ceramic as a proppant material since the ceramic system displays low acid solubility and good flexural strength.

A coral-like amorphous carbon nanotube was prepared by a modified arc discharging furnace in hydrogen atmosphere with a mixture of Mo-Co2O3-Mg powders as catalyst at 600°C. This carbon nanotube presented a microscopic coral-like by SEM observation and amorphous structure of nanotubes by HRTEM observation. The XRD diffraction and Raman pattern presented noncrystal characteristics compared to the normal graphite structure. We believed that these results may be affected by the “synergistic” effect of catalyst, atmosphere, and temperature in the synthesis process. The possible explanations to the formation mechanism of this novel carbon nanotube have also been proposed.

Single-walled carbon nanotubes (SWCNTs, the mean diameter of 1.35 nm) were produced by a modified arc discharging furnace using a mixture powder of KCl and Co-Ni alloy as catalyst at 600°C. The hydrogen storage capacity of SWCNTs was enhanced by the mechanism of atom hydrogen spillover from the supported catalyst. The temperature effect on the hydrogen storage capacity of as-grown SWCNTs was investigated. The relative experiments of SWCNT hydrogen uptake and release were carried out by a high-pressure volumetric gas-adsorption measurement system. The experimental results indicated that the hydrogen storage capacity of SWCNTs increased with the environmental temperatures decreasing. The hydrogen storage capacity of SWCNTs was up to 1.73 wt% at 77 K for 2 hours under the pressure of 10 MPa, and the corresponding releasing hydrogen capacity is about 1.23 wt% under ambient pressure.

Three-dimensional (3-D) graphene foam/PANI nanorods were fabricated by hydrothermal treatment of graphene oxide (GO) solution and sequentially in-situ synthesis of PANI nanorods on the surface of graphene hydrogel. 3-D graphene foam was used as substrate for the growth of PANI nanorods and it increases the specific surface area as well as the double layer capacitance performance of the graphene foam/PANI nanorod composite. The length of the PANI nanorod is about 340 nm. PANI nanorods exhibited a short stick shape. These PANI nanorods agglomerate together and the growth orientation is anisotropic. The highest specific capacitance of 3-D graphene/PANI nanorod composite electrodes is 352 F g−1 at the scan rate of 10 mV s−1.

This paper describes the characterization of a three-dimensional (3D) reduced graphene oxide (RGO)-carbon nanotube (CNT)-polyaniline (PANI) hybrid fabricated by combining electrophoretic deposition (EPD) and floating catalyst chemical vapor deposition (FCCVD), followed by in - situ anodic electrochemical polymerization (AEP). Firstly, the RGO-CNT is prepared by combining EPD of GO onto nickel foams (NF) and then growth of uniformly aligned CNT on the surface of RGO via FCCVD. Secondly, the 3D RGO-CNT-PANI hybrid is successfully fabricated by in situ AEP of aniline monomers onto the surface of the RGO-CNT. The structures and morphologies of the hybrid have been characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X - ray diffraction (XRD) and X-ray photoelectron spectrometer (XPS). Electrochemical properties are studied by cyclic voltammetry, galvanostatic charge/discharge measurements, and electrochemical impedance spectroscopy. The results reveal that the as-prepared hybrid based on the two - electrode system displays very high specific capacitance of 741 F g −1 with a high energy density of 92.4 Wh kg −1 and high power density of 6.3 kW kg −1 at the scan rate of 10 mV s −1 . Additionally, the hybrid shows good cycling stability with a retention ratio of 95% after 5000 cycles. These attractive results suggest that this 3D RGO-CNT-PANI hybrid has a great potential as an electrode material for high performance supercapacitors.

The improvement of high reflection loss and broad frequency bandwidth for electromagnetic wave absorption materials is a long-term effort. The superb micro-structures of the absorber have significant impact on increasing reflection loss and broadening frequency bandwidth. Herein, we prepared 3D graphene by chemical vapor deposition and then 3D graphene/pine needle-like iron nano-acicular whisker composites were in situ synthesized by an electrochemical deposition process under an electric field using 3D graphene as substrate. The nano-acicular whiskers show different sizes and the mean diameter of the individual iron nano-acicular whiskers was about 150 nm. The saturation magnetization (MS) of the 3D graphene/iron nano-acicular whisker composite was about 42.65 emu g−1 and the coercivity (Hc) was 143 Oe, and it shows good magnetic properties. In the frequency range of 2–18 GHz, the reflection loss value of the graphene/iron nano-acicular whisker composites with a thickness of 2 mm could reach −12.81 dB at 10.95 GHz and the effective absorption bandwidth below −10 dB was 2.16 GHz. The nano-acicular whiskers could effectively improve the electromagnetic wave absorbing properties. The results suggested that the as-prepared graphene/iron nano-acicular whisker nanocomposite showed great potential applications as a new absorber material.

The development of high reflection loss and broad frequency bandwidth for electromagnetic wave absorbing materials has been pursued for a long time. Constructing a rational microstructure of an absorber will have significant impact on reflection loss increase and frequency bandwidth broadening. Herein, we successfully prepare a sandwich microstructured graphene/BaFe12O19 nanocomposite by an in situ auto-combustion method. Compared to pure BaFe12O19, the sandwich microstructured graphene/BaFe12O19 showed better electromagnetic wave absorbing properties. Furthermore, the sandwich microstructured graphene/Ba0.8La0.2Fe12O19 nanocomposite was prepared with La-doped BaFe12O19 using the same method. The obtained graphene/Ba0.8La0.2Fe12O19 nanocomposite exhibited a saturation magnetization of 26.55 emu g−1 at room temperature and exhibited excellent magnetic performance. The maximum reflection loss of the sandwich microstructured graphene/Ba0.8La0.2Fe12O19 nanocomposite with a thickness of 1 mm could reach up to −40.26 dB, and a frequency bandwidth value below −10 dB was observed up to 3.87 GHz within the frequency range of 2–18 GHz.

3D dendritic Fe2O3 nanoparticles wrapped with carbon (denoted as 3DD-Fe2O3@C hereafter) were synthesized. It is found that the 3DD-Fe2O3@C is composed of α-Fe2O3 and amorphous carbon. As an anode material for lithium ion batteries (LIBs), it exhibits an excellent discharge/charge capacity (982 mA h g−1 and 971 mA h g−1 after 100 cycles at a rate of 100 mA g−1), and good cyclic stability and rate capability.

The 3D interlinked amorphous carbon nanotube (ACNT)/reduced graphene oxide (RGO)/BaFe12O19 (BF) composite was directly prepared by a self-propagation combustion process. The RGO was synthesized in situ through the massive heat release during the auto-combustion reaction. The interlinked ACNTs and graphene as well as BF formed the conductive networks for improving the dielectric and magnetic loss. The reflection loss peak of ACNT/RGO/BF composite was −19.03 dB at 11.04 GHz in the frequency range of 2–18 GHz. The frequency bandwidth of the reflection loss below −10 dB was 3.8 GHz. The 3D interlinked ACNT-RGO structure, which was composed of dense intertwined ACNT and graphene with quantities of dihedral angles, could consume incident waves via multiple reflections inside the 3D structures. The high conductivity of 3D interlinked ACNT/RGO networks would lead to energy dissipation in the form of heat through molecular friction and dielectric loss.

The composite of carbon foam with Ni-Zn ferrite as additive has been developed via foaming and carbonization process for electromagnetic interference shielding, using coal tar pitch as precursor and Ni-Zn ferrite as an additive. It was observed that the shielding effectiveness (SE) over the X-band frequency is enhanced along with the increase of Ni-Zn ferrite additive amount. The carbon foam with 15 wt% Ni-Zn ferrite shows a SE of 42 dB, which has a promising application prospect. The electromagnetic interference shielding mechanism of carbon foam with different amount of Ni-Zn ferrite additive is discussed in the work. An absorption-dominant mechanism, which is mainly associated with the magnetic property determined by the amount of Ni-Zn ferrite additive, has been revealed. It is also found that the mechanical strength of resultant carbon foams increases firstly and then decreases with the continuously increased amount of Ni-Zn ferrite additive.

In this work, we proposed a new method to prepare graphene nanosheets. Expand graphite has large sheet spacing and oil absorption, and the self-combustion precursor of BaFe12O19 is oily gel. It means that the BaFe12O19 oily gel can enter between the layers of expand graphite. When BaFe12O19 oily gel is self-combusted to form BaFe12O19 particles, it has a significant increase in volume. Expand graphite will occur secondary expansion and be peeled into graphene nanosheets. We characterized it by several ways and this is a time-saving, convenient, and low-cost method.

In this research work, low atomic number (Z) carbon ions (C+) were used to treat titanium oxide nanoparticles (TiO2-NPs) and tune their optical properties. 8 MeV C+ were irradiated on TiO2-NPs at different fluences in the ranges of 2.5 × 10 15 t o 1 × 10 16 i o n s / c m 2 to separately study their defects production and the effect on the bandgap. The C+ ion treated samples were investigated using multiple techniques such as XRD, TEM, RAMAN and PL, which confirmed increment of defects were direct proportional to the C+ fluences. The increment of defects has resulted in the bandgap reduction from 3.3 eV to 2.9 eV. Theoretical calculations using VASP by implementing density functional theory has produced comparable result. The stability of the structure after induced vacancies has been simulated and confirmed. The incorporation defects by bombardment with low Z ion could be an effective way to tune the bandgap of nanomaterials and improve its optical properties can be used in a wide variety of applications.