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Platelet graphite nanofibers (PGNFs) and turbostratic carbon nanofibers (TSCNFs) were synthesized by the pyrolysis of 3 and 10 vol% chloroform in ethanol, respectively, in the presence of Ni catalyst at 700 °C. Auger electron spectrometry analysis reveals that the participation of chloroform in the synthesis led to Ni–Cl bonding on the surface of the catalysts, resulting in a relatively poor crystalline layer and a coarse surface. Furthermore, the Ni–Cl compound affected the melting point and mobility of Ni, changing the morphology and geometrical shape of Ni particles. A low amount of chlorine in the catalyst led to the formation of smaller catalyst particles with a flat surface, resulting in graphene nanosheets stacked perpendicular to the fiber axis, which became PGNFs. In contrast, a high amount of chlorine in the catalyst led to the aggregation of the catalyst and thus the formation of large catalyst particles with a rough surface, resulting in the random stacking of graphene nanosheets, which became TSCNFs. The participation of chlorine was found to be important in the synthesis of the PGNFs and TSCNFs. [ABSTRACT FROM AUTHOR]

This study investigates nickel-doped cobalt oxide (Ni-doped Co 3 O 4) nanoparticles as catalysts for the oxygen evolution reaction (OER) in anion exchange membrane water electrolyzers (AEMWEs). Through various characterization techniques, Ni 0.45 Co 2.55 O 4 was identified as exhibiting superior OER activity compared to pristine Co 3 O 4 and other Ni-doped compositions, offering reduced overpotential and higher current density. Density functional theory (DFT) calculations provided mechanistic insights. Evaluation in an AEMWE single-cell setup confirmed Ni 0.45 Co 2.55 O 4 stability and efficiency for hydrogen production. The study underscores the importance of transitioning to renewable sources for hydrogen production and highlights the role of AEMWEs with non-noble metal catalysts in reducing costs. Moreover, it emphasizes the critical influence of the OER on AEMWE performance. Overall, the research demonstrates the potential of Ni-doped Co 3 O 4 nanoparticles as effective catalysts for sustainable hydrogen production, aligning with the goal of achieving 2050 net-zero emissions. • Ni-doped Co 3 O 4 nanoparticles were synthesized by a facile chemical synthesis combined with an annealing treatment. • Density functional theory was employed to predict reduced overpotential for Ni-doped Co 3 O 4 compared to pristine Co 3 O 4. • Ni-doped Co 3 O 4 (Ni x Co 3-x O 4) nanoparticles with particle sizes ranging from 58 nm to 164 nm. • Ni doping affects electron conductivity and cation distribution in Co 3 O 4 catalysts. • MEA with Ni 0.45 Co 2.55 O 4 anode and Pt/C cathode achieved energy efficiency of 69.4% at 300 mA cm−2 and 2.04 V. [ABSTRACT FROM AUTHOR]

A series of SrZrO3 : Eu3+ nano phosphors synthesized by a modified high‐temperature solid‐state reaction method. The structural, functional vibration groups, optical, morphological, luminescence and quantum yield studies were characterized through XRD, FTIR, UV, 'SEM & HR‐TEM' and PL analyses respectively. The SrZrO3 : Eu3+ phosphor has a perovskite orthorhombic structure and emits intense red emission around 612 nm when it is excited under 465 nm and covers NUV light range. The calculated average lifetime indicates the nature of the allowed emission transition in Eu3+ (2.44 μs). The calculated colour purity and Commission International del' Eclairagethe (CIE) chromaticity coordinates are 97.9 % and (0.5894, 0.4031) respectively. The observed quantum yield and thermal stability for the SrZrO3 : Eu3+ (9 mol %) phosphor are 22 % and 87 % at 423 K, respectively. These obtained results suggest that SrZrO3 : Eu3+ (9 mol %) phosphor would meliorate for red‐emitting phosphor in profound RGB‐based pc‐WLED applications. [ABSTRACT FROM AUTHOR]

Ti, V, Cr, Mn, Co, and Cu, have been investigated as a third dopant in NiFe sulfide for enhanced oxygen evolution reaction (OER)/oxygen reduction reaction (ORR). The effects of dopant on surface electronic structure, conductivity, and thermodynamic barrier of reaction are addressed and discussed. For the OER, X‐ray photoelectron spectroscopy analysis shows that electron transferring from the Ni to the dopants enhances the catalytic performance of the sulfide. Cu doped NiFe sulfide exhibits the best OER performance. For the ORR, density functional theory calculation indicates that Ti, V, Mn, Co, and Cu upshift the d‐band center (ɛd), while Cr downshifts the ɛd. Among the dopants, V leads to optimized electronic structure modification, giving optimized adsorption energy of *O on the Ni, the lowest rate determining step ΔG1, and the best ORR activity. By considering E10‐E1/2 together with the maximum current density of the OER and limited diffusion current density of the ORR, NiFeVS exhibits the best OER/ORR bifunctionality. The performance of NiFeVS as a cathodic catalyst has also been evaluated in a zinc air battery, demonstrating a specific capacity of 698 mAh g−1, maximum power density of 190 mW cm−2, and a superior cycle stability of 2400 cycles (400 h). [ABSTRACT FROM AUTHOR]

Abstract: The synthesis of tapered carbon nanotubes (TCNTs) by the thermal decomposition of poly(ethylene glycol) at 800°C using Ni as a catalyst is reported. The TCNTs consist of a 50nm diameter graphite tube terminated by a tapered tip, which is about 1μm in length and 20nm in diameter in the tip end. The catalyst particle contained in the tapered tip was found to be a cylindrical with a diameter of about 20nm. Electron microscopy revealed that the catalyst was a single crystal of NiCx and the graphene layers were grown in the [110] direction of the catalyst, forming TCNTs. The unique morphology of the catalyst particle played an important role in the formation of TCNTs. The field emission properties of the TCNTs exhibited a lower turn-on voltage (Eturn-on =3.2V/μm), lower threshold fields voltage (Ethreshold =5.2V/μm) and higher field-enhancement factor β than did multi-walled CNTs. [Copyright &y& Elsevier]

Abstract: Turbostratic carbon nanofibers (CNFs) with a rough surface, open pore walls, and a defect structure were continuously produced by the thermal decomposition of alcohol in the presence of an iron catalyst and a sulfur promoter at 1100°C under a nitrogen atmosphere in a vertical chemical vapor deposition reactor. A graphite exfoliation technique using intercalation and thermal shock was employed to expand the graphene layers of the as-produced turbostratic CNFs. The hydrogen storage capacity of the turbostratic CNF samples was measured using the volumetric method with a pressure of up to 1MPa at 77K. The hydrogen storage capacities of the as-produced and exfoliated turbostratic CNFs were 1.5 and 5wt%, respectively. The defects on the surface and expandable graphitic structure are considered important keys to increasing the hydrogen uptake in turbostratic CNFs. [Copyright &y& Elsevier]

Abstract: Silicon carbide nanowires (SiCNWs) were synthesized in large quantity using a thermal process with carbon nanotube (CNT)/Si–SiO2 (carbon nanotubes grown on Si–SiO2 core–shell substrates) at 1300°C in an argon atmosphere. The characterization shows that the SiCNWs covered with a thin layer of amorphous SiO2 had diameters of 30–70nm and lengths of 4–10μm. The growth mechanism of the SiCNWs is proposed to be the combination of the chemical vapor deposition (CVD) method and the CNTs confined reaction method. According to the Kubelka–Munk plot, the band gap energy for the SiCNWs was 2.8eV. The Mott–Schottky plot shows that the flat-band potential of the SiCNWs was −0.46V versus NHE and that the material exhibited n-type conductivity. The photoluminescence analysis of the SiCNWs revealed two wide bands of emission peaks centered at about 390 and 470nm (CIE value: x=0.18, y=0.24). [Copyright &y& Elsevier]

Abstract: High-purity single crystal ZnO nanowires were synthesized by the thermal decomposition of zinc acetate dihydrate at 300°C in air for 3h without a catalyst. The zinc acetate dihydrate was characterized by thermogravimetric-differential scanning calorimetry and mass spectrometry (TG–DSC–MS) to determine the thermal decomposition and crystallization temperature. Results reveal that the ZnO nanowires were produced through a dehydration, vaporization/decomposition, and deposition/formation process, which differs from the common vapor–liquid–solid (VLS) mechanism. X-ray diffraction demonstrates that the ZnO nanowires have a wurtzite crystal structure, and scanning electron microscopy shows their diameter and length to be about 40nm and a few micrometers, respectively. High-resolution transmission electron microscopy reveals that the nanowires are of a single crystal, which grew in the [001] direction. In addition, photoluminescence spectra results of the as-grown ZnO nanowires suggest possible applications in ultraviolet emission devices. [Copyright &y& Elsevier]

We report on a 20–40 s process for growing aligned, uniformed, high purity multi-walled carbon nanotubes (MWNTs) using an alcohol lamp burner. With an appropriate catalyst precursor concentration, MWNTs can be grown on a Co-coated 304 stainless steel mesh under incomplete combustion conditions at 680–700°C. The process provides a rapid, easy, economic and safe method for the formation of carbon nanotubes. We suggest that the proposed method be considered as an educational kit for college or high school level experiments. [ABSTRACT FROM AUTHOR]

Abstract: The fabrication of carbon nanocapsules and carbon nanotubes (CNTs) using an acetylene flame method was investigated. Carbon nanocapsules, a graphitic structure of nanoparticles with a hollow core, were synthesized using catalyst-free acetylene flames while CNTs were formed with the presence of cobalt-based catalysts in addition to acetylene flames. When the synthesis of these materials was carried out, the results showed that a massive amount of high-purity carbon nanocapsules with a particle size in the range of 15–30nm can be produced with the acetylene flame method. The CNTs produced were multi-walled carbon nanotubes measuring a few micrometers in length and 20–30nm in diameter. The acetylene flame method holds great potential for the cost-effective production of CNTs as well as carbon nanocapsules. [Copyright &y& Elsevier]

An 80-cm long tubular carbon coated membrane was fabricated by chemical vapor deposition (CVD) of methane on a multilayered porous ceramic substrate at a temperature of 1000 °C. The deposition of pyrocarbon on the membrane generated a carbon film, the nature of which not only reduced the pore size of the membrane but also changed the physical properties of the membrane, including its hydrophobicity, electrical conductivity, and thermal conductivity. To ensure a uniform deposition of carbon on the membrane, a CVD apparatus equipped with process piping was employed to periodically reverse the direction of the gas flow in the reactor. The CVD experiments were then conducted by varying parameters such as the rate of flow of the gas mixture (methane and nitrogen), the percentage concentration of methane, and so on. To analyze the uniformity of the carbon film, we measured the electrical resistance of the membrane and the permeation of six gases through the sectioned membranes. In the range of our study, it was found that the flow rate of the gas mixture and the alternation of the direction of the gas flow were two important factors for determining the uniformity of the carbon deposit in the membranes. Observation by scanning electron microscope (SEM) and measurement of the nitrogen permeation of the membranes revealed that fabrication of uniform carbon coated ceramic membranes with a desired pore size is possible for applications involving microfiltration, ultrafiltration, and nanofiltration. In addition, the utilization of the superior properties of the membranes such as hydrophobicity and electrical conductivity were suggested for enhancing the degree of separation of the membranes. [Copyright &y& Elsevier]

An α-Fe2O3 nanobridge (NB) was laterally grown via the one-step thermal oxidation of 150 nm Fe film at 350 °C for 1 h in air atmosphere to form a NB field effect transistor (FET). The diameter of the as-grown NB was 7 nm, with a length of 170 nm. The electrical properties of the individual α-Fe2O3 NB were directly measured by microprobing the NB FET. The results show that the NB demonstrated N-type semiconductive behavior with a conductivity of 1.67 S/cm. [ABSTRACT FROM AUTHOR]

Climate change poses a significant threat to humanity. Achieving net-zero emissions is a key goal in many countries. Among various energy resources, solar power generation is one of the prominent renewable energy sources. Previous studies have demonstrated that post-processing techniques such as bias correction can enhance the accuracy of solar power forecasting based on numerical weather prediction (NWP) models. To improve the post-processing technique, this study proposes a new day-ahead forecasting framework that integrates weather research and forecasting solar (WRF-Solar) irradiances and the total solar power generation measurements for five cities in northern, central, and southern Taiwan. The WRF-Solar irradiances generated by the Taiwan Central Weather Bureau (CWB) were first subjected to bias correction using the decaying average (DA) method. Then, the effectiveness of this correction method was verified, which led to an improvement of 22% in the forecasting capability from the WRF-Solar model. Subsequently, the WRF-Solar irradiances after bias correction using the DA method were utilized as inputs into the transformer model to predict the day-ahead total solar power generation. The experimental results demonstrate that the application of bias-corrected WRF-Solar irradiances enhances the accuracy of day-ahead solar power forecasts by 15% compared with experiments conducted without bias correction. These findings highlight the necessity of correcting numerical weather predictions to improve the accuracy of solar power forecasts. [ABSTRACT FROM AUTHOR]

Supercapacitors (SC) are essential energy storage devices for renewable energies. In this study, activated microporous carbon spheres (AMCS) and nitrogen-doped AMCS (N-AMCS) were synthesized using a modified extended Stöber method followed by CO 2 activation. A high specific area (>3400 m2 g−1) was obtained for AMCS and N-AMCS, and the diameters of the sphere could be tuned from 400 nm to 1.0 µm. The SC study revealed that the AMCS and N-AMCS achieved specific capacitances of 232.75 and 263.59 F g−1, respectively, in 6 M potassium hydroxide (KOH). The SC pouch cells were filled with aqueous, organic, and ionic liquid electrolytes. In 1 M MeEt 3 NBF 4 in acetonitrile, the energy densities of AMCS and N-AMCS were 27.96 and 31.20 Wh kg−1, respectively, at the current density of 0.5 A g−1, whereas the energy densities of AMCS and N-AMCS were 69.19 and 117.69 Wh kg−1, respectively, in EMIMBF 4. In addition, in the aqueous electrolytes, AMCS and N-AMCS had capacitance retentions of 94% and 97%, respectively, after 10,000 cycles, while the capacitance retentions of 82% and 97% were achieved with AMCS and N-AMCS, respectively, after 50,000 cycles. [Display omitted] • Size-tunable resin spheres were synthesized by the modification of the extension-Stöber method. • The AMCS with a high specific area of 3456.62 m2 g–1 and diameter of 420 nm. • The method provides a simple, cost-effective, environment-friendly and easily scalable process for production. • The pouch cells of AMCS and N-AMCS as the active materials have a good long- term cyclability. [ABSTRACT FROM AUTHOR]

Solar power has rapidly become an increasingly important energy source in many countries over recent years; however, the intermittent nature of photovoltaic (PV) power generation has a significant impact on existing power systems. To reduce this uncertainty and maintain system security, precise solar power forecasting methods are required. This study summarizes and compares various PV power forecasting approaches, including time-series statistical methods, physical methods, ensemble methods, and machine and deep learning methods, the last of which there is a particular focus. In addition, various optimization algorithms for model parameters are summarized, the crucial factors that influence PV power forecasts are investigated, and input selection for PV power generation forecasting models are discussed. Probabilistic forecasting is expected to play a key role in the PV power forecasting required to meet the challenges faced by modern grid systems, and so this study provides a comparative analysis of existing deterministic and probabilistic forecasting models. Additionally, the importance of data processing techniques that enhance forecasting performance are highlighted. In comparison with the extant literature, this paper addresses more of the issues concerning the application of deep and machine learning to PV power forecasting. Based on the survey results, a complete and comprehensive solar power forecasting process must include data processing and feature extraction capabilities, a powerful deep learning structure for training, and a method to evaluate the uncertainty in its predictions. [ABSTRACT FROM AUTHOR]

Highlights: [•] Synthesis ZnO thin film by simple method. [•] It can detect a minimum 50ppm NH3. [•] Its operation temperature can lower to 150°C. [•] Change the oxygen conc. to detect the NH3, and try to explain its mechanism. [ABSTRACT FROM AUTHOR]

Lithium-oxygen batteries (LOBs) promise high energy density but suffer from catalyst-related issues. We've developed FeNi-NCNT/DrGO, a novel catalyst, by integrating iron-nickel nanoalloys (FeNi) embedded in nitrogen-doped carbon nanotubes (NCNTs) grafted onto defect-rich reduced graphene oxide (DrGO). The fabrication involved freeze-drying, defect engineering, and thermal treatments. The FeNi nanoalloy within the catalyst demonstrates outstanding bifunctional activity, while the NCNTs serve as an excellent electronic conduction medium and DrGO enables favorable ion transport. The 3D open-space architecture of this catalyst provides a rapid diffusion path for the electrolyte and room for accommodating discharge products. As a result, the LOBs with FeNi-NCNT/DrGO exhibits exceptional electrochemical performance, achieving a deep discharge capacity of 21,153.6 mAh g−1 and a high round-trip efficiency of 98.7% at 200 mA g−1. Moreover, it demonstrates excellent cycling stability, exceeding 100 cycles at 200 mA g−1 with a cut-off capacity of 500 mAh g−1. [Display omitted] • FeNi-NCNT/DrGO was formed by freeze-drying, ball milling, and thermal treatment. • The catalyst shows superior ORR, OER, conductivity, ion diffusion and Li 2 O 2 storage. • LOB with the catalyst shows a capacity of 21153 mAhg−1 and 98.74% efficiency. • LOB exceeds 100 cycles at 200 mA g−1 with a cut-off capacity of 500 mAh g−1. [ABSTRACT FROM AUTHOR]

The commercialization of Proton Exchange Membrane Fuel Cells (PEMFCs) is hindering by the cost of noble metal catalysts. We are introducing A-Fe SAC -NC DS /rGO, a novel catalyst derived from metal-organic framework through carbonization and ammonia treatment. This catalyst is incorporating single iron atoms (Fe SAC) within dual-sized porous nitrogen-carbon frameworks (NC DS , 30 nm and 100 nm), supporting on reduced graphene oxide (rGO). The catalyst is providing abundant active sites, with NC DS increasing active site density and rGO enhancing material conductivity. Consequently, catalyst is exceling in the oxygen reduction reaction, boasting an onset potential of 0.807 V and a half-wave potential of 0.779 V, near benchmark Pt/C catalyst. PEMFC tests employing A-Fe SAC -NC DS /rGO achieved a power density of 780.7 mWcm−2 at 1.6 A cm−2 in an H 2 –O 2 system. In durability tests at 0.6 Acm−2 in H 2 -air, voltage loss was 28.68 % after 50 h. These results position the catalyst as a promising choice for PEMFC. [Display omitted] • A-Fe SAC -NC DS /rGO is derived from carbonization and ammonia treatment of MOFs. • Catalyst has abundant Fe SAC within dual-sized porous N-carbon supported on rGO. • Catalyst exhibits ORR LSV E onset and E 1/2 values close to the benchmark Pt/carbon. • PEMFC demonstrates a power density of 780.7 mWcm−2 at 1.62 Acm−2 in H 2 –O 2 system. • Durability test of PEMFC shows a voltage loss is 28.68 % at 0.6 Acm−2 after 50 h. [ABSTRACT FROM AUTHOR]

The inhibitive effects of functional groups originating from the presence of additives on corrosion are linked to the physicochemical and electronic properties of these surficial chemical species. In this work, the acetoxy group (i.e. weak bases) with different orbital characters is integrated with donating/accepting molecules which reveals dissimilar inhibitive behaviour. Introducing cations on the acetoxy groups (-Ac) as additives leads to mitigation of undesirable self-corrosion of the anode. The Al-air battery corresponded to a maximum capacity of 2817 mAhg−1 at 10 mAcm−2 with the use of barium-Ac/KOH electrolyte, demonstrates nearly 95% of the theoretical capacity. However, a capacity of only 2392 mAhg−1 is observed for free additive. In addition, the maximum power density (i.e. 91.32 mWcm−2) increased by nearly 50% with the employment of barium-Ac/KOH. The rechargeable Al–air battery based on barium-Ac/KOH presents a low voltage gap of 0.83 V with a remarkable cyclic stability of 25,000 s. The results show that the acetoxy group integrated with metal ions can be a key player in reducing H 2 evolution rate in the aluminium-air batteries. XPS analysis confirmed an Al-complex (i.e. Al-acetoxy) is formed using barium-ac. DFT calculations confirmed that barium-Ac/KOH provides the minimum value of ΔE (about 5.4 eV), indicating the remarkable ability for reacting with Al+3 ions to adsorb on the anode surface leading to complex (Ba-Ac-Al3+) formation. This study highlights the parasitic corrosion reaction leading to low coulombic efficiency in rechargeable Al- air batteries. • The impacts of additive integrated with acetoxy group was studied on Al corrosion and H2 evolution. • The corrosion inhibition efficiency follows the order of: Ba-acetoxy > Ca-acetoxy > Ethyl-acetoxy. • Ba–Ac/KOH exhibited the optimum discharge capacity 2817 mAh/g and 95% Al utilization. • XPS results revealed a complex containing Al-acetoxy contribute to reduce Al self-corrosion. [ABSTRACT FROM AUTHOR]

[Display omitted] Carbon quantum dots (CQDs) with an average diameter of 3 nm, exhibiting blue photoluminescence, have been obtained from commercial conductive carbon black by a cost-effective and straightforward exfoliation method using dry ball milling in the presence of sodium carbonate. As a secondary abrasive medium, sodium carbonate provides effective exfoliation of carbon black with a high degree of CQD graphitization and plays an essential role in the functionalization of CQDs with oxygen groups. Due to the low toxicity of CQDs against HeLa cancer cells (cell viability above 90% at a CQD concentration of 200 μg cm−3) and the ability to penetrate cells and emit blue light, CQDs are possibly suitable for biological imaging of cells. [ABSTRACT FROM AUTHOR]

Abstract: The ratio of ZnS to AgInS2 is usually adjusted to tune the band gaps of this quaternary (Ag–In–Zn)S semiconductor to increase photocatalytic activity. In this study, the [Zn]/[Ag] ratio was kept constant. The hydrogen production rate was enhanced by increasing the content of indium sulfide. Compared to the steady H2 evolution rate obtained with equal moles of indium and silver ([In]/[Ag] = 1, 0.64 L/m2 h), that obtained with In-rich photocatalyst ([In]/[Ag] = 2, 3.75 L/m2 h) is over 5.86 times higher. The number of nanostep structures, on which the Pt cocatalysts were loaded by photodeposition, increased with the content of indium. The indium-rich samples did not induce phase separation between Ag x In x Zn y S2x+y and AgIn5S8, instead forming a single-phase solid solution. Although the photocatalytic activity decreased slightly for bare In-rich photocatalysts, Pt loading played a critical role in the hydrogen production rate. This study demonstrates the significant effect of In2S3 on this unique (Ag–In–Zn)S photocatalyst. [Copyright &y& Elsevier]

Abstract: Hydroxyapatite (HA, Ca10(PO4)6(OH)2) nanoparticles were synthesized using calcining calcium dihydrogenphosphate (Ca(H2PO4)2 ·H2O), calcium hydroxide (Ca(OH)2), and polyethylene glycol (PEG) at 900 °C in an oxygen atmosphere. This one-step process yields HA nanoparticles with similar particle sizes (e.g., 50–80 nm) that are well-crystallized and non-aggregated. PEG is an important factor in controlling the particle size, crystal phase, and degree of aggregation in these HA particles. This conclusion is supported by results from a field-emission scanning electron microscope (FE-SEM), X-ray diffractometry (XRD), energy dispersive X-ray analysis (EDS), a high-resolution transmission electron microscope (HR-TEM), and dynamic light scattering (DLS). [Copyright &y& Elsevier]

Abstract: In this work, the rate of heat generation in the overcharge period for 103450 prismatic lithium ion batteries (LIBs) of the LiCoO2–graphite jellyroll type with a basic electrolyte consisting of 1M LiPF6–PC/EC/EMC (1/3/5 in weight ratio) has been found to be more important than the gas evolution which was traditionally considered as the main reason in the overcharge protection mechanism. The cell voltage, charge current, and skin temperature were monitored during the charge process. For a single battery or batteries in parallel, LIBs without any additives is an acceptable design if the cell voltage is not charged above 4.55V under the common charge program. The rate of heat generation from the polymerization of 3wt% cyclohexyl benzene (CHB) is high enough to cause the explosion or thermal runaway of a battery, which is not found for an LIB containing 2wt% CHB+1wt% tert-amyl benzene (TAB). In the 12V overcharge test at 1C, the thermal fuse was broken by the high skin temperature (ca. 80°C) due to the polymerization of 3wt% CHB, which was also the case for LIBs containing 2wt% CHB+1wt% TAB. The disconnection of the thermal fuse, however, did not interrupt the thermal runaway of LIBs without any additives because the battery voltage was too high (ca. 4.9V). The influence of specific surface area of active materials in the anode on the polymerization kinetics of additives has to be carefully considered in order to add correct amount of overcharge protection agents. [Copyright &y& Elsevier]

Abstract: Platelet graphite nanofibers (PGNFs) were synthesized by thermal decomposition from a mixture containing polymer and catalyst. The hydrogen storage capacity of the material was measured using the volumetric method carried out at 298K at a pressure up to 4.83MPa. The results show that the PGNF possess a 3.3wt.% hydrogen storage capacity. The gaseous molecules were adsorbed between two graphene planes in the PGNFs and residual amounts of hydrogen were possession within PGNFs while pressure decreased to ambient conditions. X-ray diffraction was used to understand the PGNF structural modifications before and after hydrogen uptake. We found that the PGNF interlayer undergoes expansion and returns back to the initial value before and after hydrogen uptake. [Copyright &y& Elsevier]

Abstract: The sol–gel method using and was used to prepare -doped nanopowders with particle sizes ranging from 50 to 200nm. This preparation was followed by a calcination process at . The effects which the Eu/Gd composition ratio and calcination temperature had on the phosphor structure and its luminescent properties were then investigated. Phosphor structure was examined by X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. The results confirm that the material consists of particles exhibiting good crystallinity. Photoluminescence and cathodoluminescence measurements of the particles show red emission at the 612nm () wavelength. The optimal molar concentration for obtaining the highest PL intensity for was 7% of (calcinated at for 2h). [Copyright &y& Elsevier]

• A brief summary of challenges and underlying opportunities was expressed. • This paper highlights issues related to employ liquid electrolytes in ZABs. • Various suggestions to reduce dendrites formation and ZnO layer was presented. • Additives demonstrate as promising approach for liquid and polymer electrolytes. In the past few years, there has been a growing level of interest in the research and development of energy storage systems such as batteries. This is a direct consequence of the soaring rise in global energy demand across various commercial and industrial sectors. Lithium ion batteries have set out a feasible horizon for widespread deployment as small-scale energy storage devices due to their high efficiency and cyclability. However, the availability and cost of lithium have limited the commercial deployment of large-scale systems. On the other hand, zinc-air batteries have demonstrated comparable efficiencies and have been reported to be suitable replacements for lithium batteries in large-scale applications. Nevertheless, more research has been undertaken to address the issues associated with the cycling processes of these batteries. Secondary zinc-air batteries are yet to be commercially proven feasible due to the low charge/discharge cycle life of electrodes. The main problems of secondary alkaline zinc–air batteries are dendritic growth resulting in an alternation of morphology and structure, self-dissolution and the consequent occurrence of hydrogen evolution reactions. However, by and large, inefficient electrolytes are the main culprits responsible for the reduced performance of zinc-air batteries. Therefore, a comprehensive review of current advancements in the development of suitable electrolytes to promote zinc-air batteries towards commercial application will provide a perspective for future rechargeable zinc-air batteries. In this in-depth review, the effects of the types of electrolytes and their properties on the electrochemical performance of Zn anode have been discussed. A demonstration of the current research status and challenges set upon the large-scale deployment of zinc-air batteries will facilitate the educated steering of future research directions in this critically important realm. [ABSTRACT FROM AUTHOR]

Field emission (FE) devices are advanced lighting devices that have a 2-D planar configuration, different from the 0-D (dot) and 1-D (line) configurations of light-emitting diode (LED) and fluorescent lighting, respectively. The purpose of this study is to develop a FE lighting device with a lateral-cathode triode. Carbon nanotubes (CNTs) are used as emitters and ZnS particles are used as a green phosphor. The materials were screen-printed onto two soda lime glass substrates. To increase the device lifetime and performance, we applied pulsewidth modulation (PWM) to the gate electrode. A high luminance of 12 690 cd/m2 and a good luminance uniformity of 84% were achieved for a lighting device with a lateral-cathode structure. [ABSTRACT FROM AUTHOR]

• The electrospun fiber membrane has the highest CO 2 adsorption capacity of 3.42 mmol CO2 /g adsorbent at 30 °C. • The CO 2 adsorption membrane effectively filtered carbon dioxide (400 ppm in air) for up to 16 h. • Zinc-air battery with the CO 2 adsorption membrane exhibited a higher discharge capacity. Zinc-air batteries (ZABs) are an important option for energy storage applications because of their high specific capacity. However, when ZABs are operated in ambient air, the CO 2 (400 ppm) in the air can react with the alkaline electrolyte, forming carbonates, which shorten the battery lifetime. In this work, we fabricated an electrospun polystyrene (PS)/polyethylenimine (PEI) fiber membrane to capture CO 2 from ambient air before the air is admitted into a ZAB to enhance battery performance. The result show that the PS/PEI fibers have a CO 2 adsorption capacity of 3.42 mmol CO2 /g adsorbent or 7.58 mmol CO2 /g PEI at room temperature. The fibers retain 91% of their initial CO 2 adsorption capacity after 15 cycles of the adsorption–desorption process. A ZAB cell equipped with PS/PEI fibers exhibited a better discharge capacity (802 mA h/g) compared to that of a ZAB without the fibers (762 mA h/g). [ABSTRACT FROM AUTHOR]

[Display omitted] • A Fe-Ni-Zn triple single atom catalyst is an excellent bifunctional catalyst for ORR and OER. • XAS and TEM studies confirm Fe, Ni and Zn SAC atomically dispersed in the matrix. • The SAC(Fe,Ni,Zn) with an optimal Fe/Ni ratio of 5:5 is used for ZAB. • The battery has good specific capacity(809 mAh/g @ 50 mA cm−2) and excellent power density of 300 mW cm−2 @ 406 mA cm−2. • A rechargeable Zn-air battery has superior cycle stability with 2150 cycles (358.3 h). The rechargeable Zn-air battery (ZAB) is a promising device for energy storage. A good bifunctional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) plays a decisive role in the ZAB. Here, we prepare a Fe-Ni-Zn triple single-atom catalyst (SAC) anchored in the nitrogen-doped porous carbon framework (NC) denoted as SAC(Fe, Ni, Zn)/NC or A-SAC(Fe, Ni, Zn)/NC (ammonia-treated) for the ZAB study. We found that not only Fe-N x , Ni-N x , and Zn-N x act as excellent catalytic sites for ORR and OER, but the synergetic effect by the three adjacent SAC(Fe, Ni, Zn) in the NC enhances the catalytic performance. As a result, the voltage difference (ΔE) of 0.75 V is achieved (half-wave potential of ORR: 0.88 V and the potential of OER at 10 mA cm−2: 1.63 V). In the rechargeable ZAB study, the battery with the A-SAC(Fe, Ni, Zn)/NC has a good specific capacity of 809 mAh/g @ 50 mA cm−2, the excellent power density of 300 mW cm−2 @ 406 mA cm−2 and superior cycle stability (2150 cycles, 358.3 h @ 10 mA cm−2) while the all-soild-state ZAB showed promising power density of 64.5 mW cm−2 and acceptable cycling durability over 25 h@1 mA cm−2. Triple SAC(Fe, Ni, Zn) in the hierarchical porous NC possesses the bifunctional catalytic capability, high ionic diffusivity, and electron conductivity. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable Zn-ion batteries (ARZIB) are promising candidates for next-generation batteries because of their high safety, low cost, and relatively high capacity. In this study, we developed hydrated and potassium-doped manganese dioxide (MO) nanowires mixed with carbon nanotubes (CNT) on a graphene substrate (hydrated KMO-CNT/graphene) for ARZIB. A simple polyol process using poly(ethyl glycol), KMnO 4 , CNT, and graphene was utilized to fabricate hydrated KMO-CNT/graphene. MnO 2 nanowires with diameters of 15–25 nm possess a high specific capacity with a short diffusion path. The intercalated K ions and hydrates in the layered MnO 2 nanowires maintained the MO structure during the charge and discharge processes, whereas carbon nanomaterials (CNT and graphene) enhanced the conductivity of the material. Consequently, hydrated KMO-CNT/graphene demonstrated good ARZIB performance. A high capacity of 359.8 mAh g–1 at 0.1 A g–1, and at a high current density of 3.0 A g–1, a capacity of 129 mAh g–1 with 77% retention after 1000 cycles, were achieved. • Hydrated and potassium-doped MnO 2 mixed with CNT on graphene substrate is synthesized. • Polyol process was conducted with PEG, KMnO 4 , CNT and graphene. • MnO 2 has a high capacity, intercalated K and H 2 O keep the structure of MnO 2 and CNT/graphene provide conductivity. • The hydrated KMO-CNT/graphene delivers high specific capacities of 359.8 mAh g–1 at 0.1 A g–1 and 129 mAh g–1 at 3.0 A g–1 with 77% retention. • The performance of ZIB reaches a high energy density of 410.36 Wh kg–1 at 109.93 W kg–1. [ABSTRACT FROM AUTHOR]

Urchin-like α-Fe 2 O 3 microspheres (radial α-Fe 2 O 3 nanowires on α-Fe 2 O 3 microspheres) are used as field emitters for a flat-panel lighting device with a lateral-gate-electrode structure. The urchin-like α-Fe 2 O 3 microspheres are in situ grown on the cathode electrode via thermal oxidation at 350 °C for 12 h after the screen-printing of pattern Fe microspheres on the cathode electrode. The lateral-gate triode structure comprises an Ag cathode and a pair of Ag gate electrodes screen-printed laterally on both sides of the cathode. The role of the gate electrodes is to enhance the emission current and increase luminance uniformity and that of the anode electrode is to control the luminance intensity. The radial nanowire emitters on the spheres ensure good field emission performance without any pretreatment and in situ growth of the material enhances the contact between the electrode and the material. The microspheric emitters and the lateral-gate structure, which covers a small part (4.32%) of the printed area over the entire panel (3.5 cm × 5 cm) leads to, high luminance, excellent luminance uniformity and tunable luminance characteristics of the field-emission light source. A maximum luminance of 8330 cd/m 2 and a luminance uniformity of 92.4% are achieved with a gate voltage of 500 V, an anode voltage of 4000 V, and the anode current of 1.32 mA. [ABSTRACT FROM AUTHOR]

Urchin-like CuO microstructures were formed using simple, template-free, one-step thermal oxidation of Cu solid microspheres in an air atmosphere at temperatures ranging from 350 to 500 °C. The urchin-like CuO microstructure consists of crystalline CuO nanowires grown radially on the surface of the sphere, a shell layer of CuO a few micrometers in thickness, and a hollow core. Study of the formation mechanism revealed that during oxidation, the nanowires grow from the surface, and the diameter, length, and population density of the nanowires increase with the oxidation time. For a sample formed at 450 °C for a dwell time of 24 h, the average diameter, length, and population density of the nanowires were 44.0 nm, 11.5 μm, and 25 nanowires/μm 2 , respectively. The novel urchin-like structure and high aspect ratio of the nanowires elicit unique properties. Study of the magnetic properties revealed that the urchin-like CuO is a semihard magnetic material with a coercive force of 135 Oe. Studies on the field-emission characteristics of the material demonstrated that an urchin-like emitter had a low turn-on field of 2.94 V/μm, a high field enhancement factor of 3715, a high luminance of 11,080 cd/m 2 , an excellent emission uniformity of over 3.5 × 3.5 cm 2 , and high emission stability during a 50-h test at a current density of 100 μA/cm 2 . [ABSTRACT FROM AUTHOR]

[Display omitted] • The novel CNT-CoFe/NC and CNT-CoS 2 Fe/NC was fabricated by thermal treatments and vulcanization. • CNT-CoFe/NC shows a better ORR performance than Pt/C while CNT-CoS 2 Fe/NC shows a better OER performance than RuO 2. • The hybrid catalysts, CNT-CoFe/NC + CNT-CoS 2 Fe/NC, demonstrate a superior performance of rechargeable Zn-air battery. Catalysts with embedded and functionalized elements used for the effective control of oxygen-reduction (ORRs) and oxygen-evolution reactions (OERs) are the key to developing high-performance rechargeable Zn–air batteries (ZABs). Here, carbon nanotube-grafted, Co–Fe embedded, nitrogen-doped porous carbon nano-frameworks (CNT–Co–Fe/NC) were synthesized through the carbonization of Fe-doped zeolitic imidazolate frameworks and vulcanization of the CNT–Co–Fe/NC to form CNT–CoS 2 –Fe/NC. The CNT–CoS 2 –Fe/NC exhibited a superior OER performance with an overpotential of only 1.637 mV at a current density of 10 mA/cm2 and a Tafel slope of 197 mV/dec (which, for RuO 2 , is 112 mV/dec), whereas the CNT–Co–Fe/NC showed an excellent ORR performance with a Tafel slope of 71 mV/dec (which, for 20 wt% Pt/C, is 91 mV/dec). A ZAB was developed with a hybrid catalyst of 50 wt% CNT–Co–Fe/NC and 50 wt% CNT–CoS 2 –Fe/NC in the cathode, and it achieved an excellent specific discharge capacity of 814 mAh/g at 50 mA/cm2, high power density of 245 mW/cm2, and outstanding cycle stability of over 1800 cycles (300 h) at 10 mA/cm2 with a very high retention of 95% and small potential gap of 0.68 V, compared to the corresponding values of 803.7 mAh/g, 215.3 mW/cm2, 900 cycles: retention 92%, and potential gap 0.837 V for 150 h for the ZAB with a hybrid catalyst of Pt/C + RuO 2. It is hypothesized that the ZAB with the novel hybrid catalyst exhibits its excellent catalytic activity and durability as a result of the synergistic effect of the catalyst's embedded heteroatoms and nitrogen–metal/carbon framework that enhances the ORR/OER performance, porous carbon nano-framework that enables rapid diffusion and electrical conduction, and carbon nanotubes that complete the external electrical connection between the catalysts. [ABSTRACT FROM AUTHOR]

Graphene quantum dots (GQDs) were formed by liquid-phase exfoliation in an ultrasonic bath using platelet graphite nanofibers (PGNFs) as the raw material and dimethyl sulfoxide (DMSO) as the exfoliation agent. PGNFs, carbon fibers with graphene nanosheets stacked perpendicular along the fiber axis, were sectioned layer by DMSO for 3 h with ultrasonic assistance to create GQDs. The diameters of the derived GQDs were in the range of 10–30 nm and fewer than five graphene layers were formed. X-ray photoelectron spectroscopy analysis revealed that no functional groups were grafted onto the GQDs during the process, indicating that the synthetic route produced high-quality GQDs. [ABSTRACT FROM AUTHOR]

• Development of lithium metal based anode through novel Semi-infusion technique. • Ni mesh to be act as a host material to accommodate li ions during stripping/plating. • The symmetrical Li/SnO 2 -Ni cell revealed a low voltage gap of ∼ 8 mV over 2000 h at 1 mA cmˉ2 and 1 mAh cmˉ2. • Full cell cycling performance of the Li/SnO 2 -Ni with LFP delivered a specific capacity of 170 mAh gˉ1 with an excellent stability. Lithium metal battery is a promising candidate for the next generation batteries due to its high theoretical specific capacity and energy density. However, the dendritic propensity of Li metal and inevitable volume variation are critical obstacles for commercialization. Here, we prepare a novel anode that Li infused partially into the tin oxide coated Ni mesh (Li/SnO 2 -Ni) by semi-infusion strategy. The strategy can provide an adequate but not excessive amount of Li in the host for the battery. The SnO 2 -Ni mesh abates the dendritic formation and volume variation due to its lithiophilic property, three-dimensional (3-D) structure, and excellent conductivity guiding the Li-ion deposition and stripping uniformly during cycling. As a result, Li/SnO 2 -Ni cell can cycle a long span with an exceptionally low voltage gap of 8, 15, and 200 mV at a different current density and of 1, 3, and 35 mA cm−2, and a capacity of 1, 1 and 5 mAh cm−2, respectively, in a symmetrical cell. The performance of full cell against LiFePO 4 cathode achieves a superior capacity of 173 mAh g−1 at 0.2 C and the retention of 90 % after 70 cycles. This work offers a facile and effective strategy to fabricate a 3-D composite anode and promotes the practical applications of Li metal batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

A double-sided light source based on field emission (FE) using an alternating current (ac) power source is demonstrated. Electrode plates acted as cathode or anode consisting an indium tin oxide glass, a screen-printed ZnS phosphor layer and urchin-like \alpha\-Fe2O3 emitters coated on the layer. Two pieces of the plates were assembled together with the coated surfaces facing each other to make a parallel-plate, diode-structure FE device with a gap distance of 300 \mum. The 1-cm^2 device shows a double-sided luminance distribution with a turn-on field of 2.2 V/\mum, 90.23% uniformity and a maximum luminance of 8750 cd/m^2 at 2 kV. The novel structure and ac model operation provide a double-sided luminance, high brightness, antiarcing, good thermal management, and long lifetime. [ABSTRACT FROM PUBLISHER]

• Development of lithium-metal-based anodes based on Li infusion technique is reviewed. • Several three-dimensional substrates designed to withhold molten Li are discussed. • The roles of porosity, lithiophilicity, and conductivity for anodes are discussed. • Unsolved issues and further research considerations are summarized. Lithium-metal-based anodes (LMA) are known to be most propitious for high-energy rechargeable batteries owing to their extremely high theoretical specific capacity (3860 mAh/g) and low electrode potential. Despite this, uncontrollable dendrite growth and large volume change are regarded as the main barriers to their commercialization. Various approaches for anode modification have been proposed to overcome these barriers. Unfortunately, the formation of short filamentous dendrites with various morphologies is still a problem to be addressed. For constructing stable anodes, lithium infusion is considered to be the most efficient strategy for confining the growth of dendrites and volume change. In this review, we dedicate recent advancements in a variety of porous substrates and their impacts on lithium infusion. We firmly believe that this review could dispense an effective facet for mitigating the mentioned issues and excel the superior performances. [ABSTRACT FROM AUTHOR]

Abstract: A double-sided surface light source based on field emission (FE) using an alternating current power source is demonstrated. Carbon-nanotube (CNT) emitters and ZnS phosphor are mixed and screen-printed onto two pieces of indium tin oxide glass that were assembled together with the coated surfaces facing each other to make a parallel-plate, diode-structure FE device. The device has a double-sided luminance distribution with a turn-on field of 2V/μm, a good uniformity, and a stable luminance of 4000cd/m2. The results show that CNTs not only act as good field emitters but also as an electrically conductive network around the isolated phosphors. The network prevents electric arcing and thus extends the lifetime of the device. [Copyright &y& Elsevier]

Abstract: Thin-walled carbon nanotubes (TWCNTs) were synthesized using a zirconium (Zr) plate by cold-wall chemical vapor deposition of a mixture gas consisting of C2H2 and H2 under a pressure of 1.20torr. The Zr plate was used for the formation of Zr nanocatalysts during the thermal process and used as substrate to eliminate the effects of interactions between catalyst and substrate during CNT synthesis. The TWCNTs were 4–9nm in diameter and a few micrometers long. Nanometer-sized defects on the Zr bulk material may have a low melting temperature, allowing them to form droplet-like catalysts and achieve high carbon solubility for the formation of CNTs. [Copyright &y& Elsevier]

Abstract: The combination of porous carbon nanofiber (PCNF) and room-temperature ionic liquid (RTIL) provided a suitable microenvironment for heme-proteins to transfer electron directly. Hemoglobin, myoglobin, and cytochrome c incorporated in PCNF/RTIL films exhibited a pair of well-defined, quasi-reversible cyclic voltammetric peaks at about −0.28V vs. SCE in pH 7.0 buffers, respectively, characteristic of the protein heme Fe(III)/Fe(II) redox couples. The cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize the modified electrode. The heme/PCNF/RTIL/CHIT films were also characterized by UV–vis spectroscopy, indicating that heme-proteins in the composite film could retain its native structure. Oxygen, hydrogen peroxide, and nitrite were catalytically reduced at the heme/PCNF/RTIL/CHIT film modified electrodes, showing the potential applicability of the films as the new type of biosensors or bioreactors based on direct electrochemistry of the redox proteins. [Copyright &y& Elsevier]

Abstract: The 3D mesoporous, well crystalline RuO2 film prepared via the evaporation-induced self-assembled method (EISA) successfully demonstrates the extremely high power performances (e.g., excellent capacitive behavior at 10,000mVs−1, ultrahigh-frequency capacitive responses (the absence of a knee point in the Nyquist plot), and 2.6MWkg−1 with an acceptable energy density of 4.6Whkg−1). These excellent capacitive performances were identified by means of voltammetric and electrochemical impedance spectroscopic (EIS) analyses. The mesoporous (with mean pore spacing of 18.1nm) and crystalline nature of this film was characterized by means of the field emission scanning electron microscopy (FE-SEM), Brunaur–Emmett–Teller (BET) method, small-angle X-ray scattering (SAXRS), high-resolution transmission electron microscopy (HR-TEM), electron diffraction (ED), and X-ray diffraction (XRD) analyses. This mesoporous, well crystalline RuO2 film constrains the redox transition to the superficial region meanwhile the tailored mesoporous structure increases the electrochemically active centers, promotes the penetration of electrolytes, provides the “proton reservoirs”, and enhances the rate of electron transport simultaneously for the ultrahigh power application. The specific capacitance of this mesoporous RuO2 can be enhanced from 84 to 185Fg−1 after the microwave-assisted hydrothermal treatment. [Copyright &y& Elsevier]

Abstract: High-purity carbon spheres were continuously produced by pyrolysis of acetylene at 1000 °C under a nitrogen atmosphere in a vertical chemical vapor deposition reactor. The produced carbon spheres had diameters in the range of 200–500 nm and were perfectly spherical in shape with rough surfaces. High resolution transmission electron microscopy analysis revealed that the carbon spheres were constructed of heavily distorted graphene layers. The results of the X-ray diffraction pattern and Raman spectra also confirmed that the presence of disordered graphene layers was due to a low graphitization degree. In addition, thermal stability and thermal oxidation of carbon spheres were studied. The results found that the surface of the carbon spheres could be modified and the amount of oxygen-containing functional groups increased after oxidation. In summary, the method provided a catalyst-free, substrate-free, hydrogen-free, and cost-effective synthesis for continuous production of carbon spheres. [Copyright &y& Elsevier]

Abstract: Turbostratic carbon nanofibers (CNFs), platelet graphite nanofibers (PGNFs) and tubular graphite nanofibers (TGNFs, also called multi-walled carbon nanotubes) were synthesized using thermal decomposition from a mixture of poly(ethylene glycol) and NiCl2. A detailed study found that the synthesis temperature dramatically affected the morphology and topography of the catalysts, which play an important role in the synthesis of the various CNFs. At the temperature of 600°C, irregular shape nanocatalysts with very rough surfaces were formed for the synthesis of turbostratic CNFs. Cubic-like nanocatalysts were formed at 750°C for PGNFs and truncated cone-like nanocatalysts were formed at 850°C for TGNFs. The surface roughness and the shape of the catalysts determined the stacking order of the graphene layers so that different types of CNF were formed. The growth direction of the graphene layers was from the Ni(111) plane for PGNFs and from the Ni(110) plane for TGNFs. Characterizations and field emission properties of these materials were also studied and compared. [Copyright &y& Elsevier]

Abstract: A red-emitting phosphor material, Gd2Ti2O7:Eu3+, V4+, by added vanadium ions is synthesized using the sol–gel method. Phosphor characterization by high-resolution transmission electron microscopy shows that the phosphor possesses a good crystalline structure, while scanning electron microscopy reveals a uniform phosphor particle size in the range of 230–270nm. X-ray photon electron spectrum analysis demonstrates that the V4+ ion promotes an electron dipole transition of Gd2Ti2O7:Eu3+ phosphors, causing a new red-emitting phenomenon, and CIE value shifts to x=0.63, y=0.34 (a purer red region) from x=0.57, y=0.33 (CIE of Gd2Ti2O7:Eu3+). The optimal composition of the novel red-emitting phosphor is about 26% of V4+ ions while the material is calcinated at 800 °C. The results of electroluminescent property of the material by field emission experiment by CNT-contained cathode agreed well with that of photoluminescent analysis. [Copyright &y& Elsevier]

Abstract: Porous carbon nanofibers (CNFs) enriched with the graphitic structure were synthesized by thermal decomposition from a mixture containing polyethylene glycol and nickel chloride (catalyst). The textural and electrochemical properties of porous CNFs were systematically compared with those of commercially available multi-walled carbon nanotubes (MWCNTs). The high ratio of mesopores and large amount of open edges of porous CNFs with a higher specific surface area, very different from that of MWCNTs, are favorable for the penetration of electrolytes meanwhile the graphene layers of porous CNFs serve as a good electronic conductive medium of electrons. The electrochemical properties of porous CNFs and MWCNTs were characterized for the application of supercapacitors using cyclic voltammetry, galvanostatic charge–discharge method, and electrochemical impedance spectroscopic analyses. The porous CNFs show better capacitive performances (C S =98.4Fg−1 at 25mVs−1 and an onset frequency of behaving as a capacitor at 1.31kHz) than that of MWCNTs (C S =17.8Fg−1 and an onset frequency at 1.01kHz). This work demonstrates the promising capacitive properties of porous CNFs for the application of electrochemical supercapacitors. [Copyright &y& Elsevier]

Abstract: Ultraviolet and visible-light-responsive titania was synthesized and employed in the NO x photomineralization. A thermal decomposition reaction of titanium isopropoxide was carried out with a metal-organic chemical vapor deposition (MOCVD), enabling continuous production of TiO2 nanoparticles. Carbon-containing titanium dioxide with the anatase phase prepared at 500°C under nitrogen atmosphere exhibited high photocatalytic activity for NO oxidation under visible-light illumination. Experimental results indicate that up to 48% removal of NO x can be achieved in a continuous flow type of reaction system under visible-light illumination (green LED). The chamber temperature in this MOCVD process plays an important role in lattice structure formation, and also affected TiO2 carbon content. The carbonaceous species on the TiO2 surface, shown by X-ray diffractometry (XRD), and Raman, UV–vis, and X-ray photoelectron spectroscopies (XPS), is important to the visible-light absorption and visible-light-catalytic mineralization of NO x . [Copyright &y& Elsevier]

Abstract: Multiwalled carbon nanotubes (MWNTs) were synthesized using a chemical vapor deposition floating feed method in a vertical reactor. Effects of the preparation variables on the average diameter of carbon nanotubes were systematically examined using the fractional factorial design (FFD), path of the steepest ascent, and central composite design (CCD) coupled with the response surface methodology. From the FFD study, the main and interactive effects of reaction temperature, methane flow rate, and chamber pressure were concluded to be the key factors influencing the diameter of MWNTs. Two empirical models, representing the dependence of the diameter of carbon nanotubes at the vicinities around maximum (420nm) and minimum (15nm) on the reaction temperature and methane flow rate, were constructed in two independent CCD studies. These models, shown as contour diagrams, indicated that the diameter of carbon nanotubes generally increased with increasing reaction temperature and methane flow rate. Based on both models, the diameter of MWNTs from 15 to 420nm can be controlled precisely by using a continuous CVD fabrication method. [Copyright &y& Elsevier]

The aim of this study is to investigate the possibility of using a polymer material, polyvinyl alcohol (PVA), as an additional carbon source to fabricate carbon nanotubes using arc-discharge method. Experiments were carried out using a graphite anode filled with a mixture of PVA and iron group catalysts. The results indicated that PVA material not only can be used for the formation of carbon nanotubes but also for the formation of some novel carbonaceous structures such as spherical nanoparticles, beaded and sheet-like carbon nanostructures. Furthermore, we found that the catalyst content in the PVA filling mixture should be lower than 50 wt%. In addition, novel catalyst precursors, such as Fe2(SO4)3 · nH2O or Fe(NO3)3 · 9H2O, were employed to grow carbon nanotubes. The results showed that these catalyst precursors can be used to form carbon nanotubes if their filling content does not exceed 50 wt%. [Copyright &y& Elsevier]

The influence of various sulphur-oxygen (SO) group additives has been investigated in retarding the self-corrosion of Al anode in a 4M KOH solution, in order to effectively enhance the overall performance. The studied additives in this work were all found to be capable of decreasing H 2 evolution, and could mitigate aluminium self-corrosion, with the corrosion inhibition towards the cathodic protection process. The less pitting corrosion and holes were observed for inorganic additives in comparison to the organic counterparts. The Al-air batteries demonstrated an improvement in the discharge capacities: 2604, 2393, 2348 and 2048 mAh g−1 for Na 2 SO 4 , Na 2 SO 3 , C 2 H 6 SO, and C 6 H 5 SO 2 OH, respectively, in comparison to that associated with the 4M KOH (2021 mAh g−1). K 2 S 2 O 8 , an inorganic additive, exhibited a hydrogen evolution efficiency of 21%, but the lowest discharge performance (1973 mAh g−1). This may be due to the instability of the anions in redox reactions. The low inhibition efficiency of the hybrid additives in Al self-corrosion, when compared to single additives, may be ascribed to the involvement of Al3+ in complex formation of the inorganic-organic hybrid additives. A stable discharge-charge cycling test over 6 h with a voltage gap of around 0.7 V is observed for Na 2 SO 4 , demonstrating the efficient performance compared to the additive-free KOH electrolyte. It could be concluded that efficient additives containing SO group, successfully mitigated the self-corrosion and hydrogen evolution associated with the Al anode that was confirmed with DFT results. [ABSTRACT FROM AUTHOR]

Silicon is regarded as one of the most promising anode materials for high performance lithium-ion battery (LIB) due to its high theoretical specific capacity. However, the low electrical conductivity and the severe volume change during charging and discharging process result in poor cyclic performance. In this study, a low cost, high-purity silicon powder from the sawing waste in photovoltaic industry was used as the active material. Pitch from petroleum residue was used as carbon source to provide a good conductive pathway and prevent the drastic volume changes of Si. The pitch-based silicon-carbon composites with a porous structure were fabricated by electrospraying technique followed by a sequence of thermal processes. The results of the charge/discharge showed that the 100th charge capacity of 1515 mAh/g at 0.2 C with the retention of 73.95% while the 200th charge capacity of 929 mAh/g at 0.5 C with the retention of 70.61% (Pitch-Si-0.5) can be obtained. On the other hand, the sample with medium content of Si showed charge capacity of 522 mAh/g at 0.5 C with the extremely high retention of 94.99% after 200 cycles. The rate capability indicated that the soft carbon derived from pitch provided a good rate capability because of its amorphous structure. We demonstrated that industrial wastes can form a superior anode material for LIB application. • Spherical silicon-carbon composite was formed as an anode material for LIB. • Silicon was from the waste of the photovoltaic industry and the source of the carbon is petroleum pitch. • The composite demonstrated an excellent capacity and stability (1515 mAh/g at 0.2C, 73.95% retention at 200th cycle). [ABSTRACT FROM AUTHOR]