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Electrochemical catalysts for the hydrogen evolution reaction (HER) have attracted increasing attentions. Noble metal-free cocatalysts play a vital role in HER applications. Herein, a novel strategy to prepare a Ni2P/MoS2 cocatalyst through a simple hydrothermal-phosphorization method was reported, and the prepared cocatalyst was then loaded on an N-doped carbon substrate with excellent conductive performance. The large surface area of the carbon substrate provided many active sites, and the interface between Ni2P and MoS2 improved the catalytic performance for the HER. Compared with pure Ni2P catalyst and MoS2 catalyst, the prepared Ni2P/MoS2 cocatalyst exhibited enhanced catalytic performance. In addition, the results indicate that the prepared cocatalyst has a wide pH range and low onset potential values of 280, 350 and 40 mV in acidic, phosphate-buffered saline and alkaline solutions, respectively, and the corresponding Tafel slopes are 75, 121 and 95 mV dec−1, respectively. Density functional theory (DFT) was adopted to calculate the hydrogen adsorption free energy (△GH∗). The results showed that the interface between Ni2P and MoS2 reduced △GH∗, which was beneficial to the adsorption of hydrogen. Present preparation of cocatalysts with unique interfaces provides a new strategy for improving the catalytic performance of HER.

Biomass-based carbon aerogels have attracted significant research attention due to the wide range of raw material, low cost, and environmental friendliness. In this study, green and sustainable carbon aerogels have been prepared using starch as raw material. Potassium chloride and potassium carbonate have been selected as template and activator. Due to the joint action of potassium chloride and potassium carbonate, the starch-based carbon aerogels exhibit a specific surface area of 2367 m2 g-1 with ant-hole-like 3D network pore structure. The starch-based carbon aerogels have been further employed as the electrode material for supercapacitors. The specific capacitance of the carbon aerogels is 292.3 and 245 F g-1 at current densities of 1.0 and 10 A g-1, respectively. In addition, the starch-based carbon aerogels demonstrate excellent sorption ability for oil and organics as well as insignificant sorption ability for H2O, thus, indicating their potential use as optimal oil-water separation material.

Supercapacitors are promising for high power application in the recent years. In particular, the conversion of simple and available carbon materials into economic and high performance electrical devices receives excellent scientific and technological interest. This paper reports a one-step strategy for synthesizing hierarchical porous carbon derived from phenolic resin (PR), which is then used to configure electric double-layer capacitors (EDLCs). Here, a carbon material with a flexible porous structure, large specific surface area, and high graphitization degree is prepared using potassium ferrate (K2FeO4) to catalytically activate PR and to realize synchronous carbonization and graphitization. This method overcomes the disadvantage of time-consuming, high-cost, and environmentally unfriendly. In addition, the as-prepared carbon material has a high specific surface area (1086 m2 g−1) and a large pore size (3.07 nm), which can increase the transfer rate of electrolyte ions. The specific capacitance of the obtained electrode material is 315 F g−1 at 1.0 A g−1, and the optimized electrode material has an ultra-long cycle lifetime (capacitance retention rate is 96.3% after 10,000 cycles). Thus, the hierarchically Fe-doped porous carbon material derived from PR material is expected to realize high rate capacitance for supercapacitor applications.

Carbon aerogels with excellent conductive characteristics and high specific capacitance have attracted more and more interests for next-generation energy storage applications. Three-dimensional interconnected Mn2O3/carbon aerogel supercapacitor electrodes are prepared by a novel doping method using MnO2 coordinated by N, N-dimethylmethanamide (DMF). The coordinative MnO2 (DMF/MnO2) plays a key role in the sol-gel process of resorcinol and formaldehyde. The doped carbon aerogels exhibits a high specific surface area of 859 m2 g−1 and a good pore-size distribution of 10–15 nm. All of the doped carbon aerogels exhibit higher specific capacitance than pure carbon aerogels, and the highest specific capacitance (170 F g−1), at current density of 1.0 A g−1, is obtained in Mn–CA–5% when 5 mol% DMF/MnO2 is added to the precursor solution. The specific capacitance is as high as 100 F g−1, at current density of 10.0 A g−1, and 97% of initial capacitance is retained over 1000 cycles at a current density of 5.0 A g−1. The doped carbon aerogels exhibits a high coulombic efficiency (up to 99.8%) and a good rate capability. The corresponding result is due to the novel doping method of DMF/MnO2 addition.

A new ternary poly(e-caprolactone) (PCL)/poly(ethylene oxide) (PEO)@AuNPs composite material with high catalytic activity and favorable structural stability has been successfully prepared. The prepared PCL/PEO composite fibers by electrospinning have been treated with an easy-to-operate solvent vapor annealing (SVA) process, demonstrating wrinkled fiber nanostructures, promoting the significantly high specific surface area and more active sites in the surface of electrospun fiber. Then NaBH4 was used as a reducing agent to reduce HAuCl4 to form gold nanoparticles, resulting in the targeted PCL/PEO@AuNPs composite material. The obtained PCL/PEO@AuNPs composites demonstrated potential catalytic ability and good reusability in the catalytic reduction of 4-nitrophenol and 2-nitroaniline systems, showing promising and wide applications in catalytic composite materials and self-assembled films.

d-cysteine (d-cys) has been demonstrated to possess an extraordinary antibacterial activity because of its unique steric configuration. However, inefficient antibacterial properties seriously hinder its wide applications. Here, cysteine-functionalized gold nanoparticles (d-/l-Au NPs) were prepared by loading d-/l-cysteine on the surface of gold nanoparticles for the effective inhibition of Escherichia coli (E. coli) in vitro and in vivo, and the effects on the intestinal microflora in mice were explored during the treatment of E. coli infection in the gut. We found that the antibacterial activity of d-/l-Au NPs was more than 2–3 times higher than pure d-cysteine, l-cysteine and Au NPs. Compared with l-Au NPs, d-Au NPs showed the stronger antibacterial activity, which was related to its unique steric configuration. Chiral Au NPs showed stronger destructive effects on cell membrane compared to other groups, which further leads to the leakage of the cytoplasm and bacterial cell death. The in vivo antibacterial experiment illustrated that d-Au NPs displayed impressive antibacterial activity in the treatment of E. coli-infected mice comparable to kanamycin, whereas they could not affect the balance of intestinal microflora. This work is of great significance in the development of an effective chiral antibacterial agent.

Porous biomass-carbon materials for supercapacitor applications have recently attracted attention. Chitin, which has abundant amides and hydroxyl groups, was used as an ideal precursor for carbon in this work. The chitin was treated with a one-step method to produce a heteroatom-loaded porous carbon material, and its electrochemical properties were significantly improved through the introduction of loaded elements. A mixture of chitin, zinc chloride, and heteroatoms was carbonized to obtain heteroatoms (N and S) and the bimetallic sulfide loaded hierarchical porous carbon. Then, the porous carbon with S, N, Zn, and Fe heteroatoms loading was used to prepare a supercapacitor with a specific capacitance of 277.4 F g−1 at 1 A g−1. In addition, the supercapacitor had a specific capacitance retention rate of 90% at 5 A g−1 after 10,000 cycles. Therefore, hierarchical porous carbon materials loaded with heteroatoms and bimetallic sulfide were prepared by carbonization activation with chitin as the precursor. The resulting supercapacitor showed that the as-prepared porous biomass materials possessed ideal charging-discharging performance. Moreover, this work provides strategies for obtaining metal sulfides and heteroatom co-loading of carbon materials with excellent properties using a simple and efficient one-step method for renewable energy storage device applications.

Improving the specific capacitance of carbon aerogels in supercapacitors and maintaining their high specific surface area remained an important challenge. Here, we prepared resorcinol–phloroglucinol–formaldehyde carbon aerogels reduced with hydrazine hydrate by a microwave method. The effects of the amount of hydrazine hydrate and the time of microwave reaction on the electrochemical performance of carbon aerogels were investigated. The reductive carbon aerogels were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The XPS spectra of reductive carbon aerogels indicated a presence of four nitrogen N1s groups, three oxygen O1s groups and six carbon C1s groups in the deconvoluted spectra. Surface area analysis and electrochemical performance were also investigated. The results showed that the specific surface area of the N-doped carbon aerogels could be as high as 803 m2 g−1. According to the electrochemical testing results, the specific capacitance of the N-doped carbon aerogels significantly increased and reached 219 F g−1 at a current density of 1.5 A g−1 compared to the pristine carbon aerogels. The optimal dosage and time of hydrazine hydrate was 20.6 mol L−1 for 25 min. The N-doped carbon aerogels electrode exhibited excellent reversibility with a cycling efficiency of 93.6% after 10000 cycles.

Ternary carbon aerogels (CAs) were fabricated via a sol–gel process using resorcinol–formaldehyde (R–F), hydroxyethyl cellulose (HC) and carbon fibers (CFs) in the presence of an acid–base catalyst. The acid–base catalyst was composed of ascorbic acid (VC) and sodium carbonate. The products were carbonized at 900 °C in a nitrogen atmosphere. The effects of the acid–base catalyst on the structure and the electrochemical properties of the resulting CAs were studied. The textural and electrochemical properties were investigated by variable instruments (e.g. scanning electron microscopy (SEM), transmission electron microscopy (TEM), an ASAP 2420 surface-area analyzer, and a GAMRY Interface 1000 electrochemical workstation). These tests showed that, when the molar ratios of F/R, VC/R and Na2CO3/R were 2, 0.02 and 0.002, respectively, and the mass ratios of HC/R and CF/R were 0.09 and 0.005, respectively, the specific surface area of the resulting CA was 1071 m2 g−1 and its specific capacitance was 131 F g−1; both of these values are substantially better than those in prior reports.

Electrocatalytic water splitting for hydrogen production is highly desirable to replace oil energy. The catalytic performance is closely related to the conductivity, active sites and reaction Gibbs free energy of the catalyst. A general guideline for improving catalytic performance is to obtain porous carbon-based materials with a high surface area, plentiful defects and metal compound loading. Here, defect-rich nitrogen-doped reduced graphene oxide (RGO) with molybdenum (Mo)-based compound loading was designed through a two-step method. The peroxide-assisted step under low-temperature carbonization with an air atmosphere promotes the formation of defects, and the hydrothermal process improves the crosslinking degree to form a porous structure at a high carbonization temperature. The obtained catalysts exhibit excellent and durable electrocatalytic performance over a broad pH range. In addition, the transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) results clearly reveal the presence of defects. The theoretical analysis demonstrates that the RGO and Mo-based compounds have an efficient synergetic effect on the catalytic activity. This work provides clues for the development of new catalysts for water splitting to produce hydrogen.

In this study, a 3D Fe-based and N-doped coral-like carbon composite (Fe-NGLC) was successfully prepared via the simple impregnation of a self-made 3D nitrogen-enriched and porous layered graphene-like support with Fe2(SO4)3 as the precursor. It was characterized through X-ray diffractometry, scanning electron microscopy, X-ray photoelectron spectroscopy, etc.; Fe-NGLC exhibited regular three-dimensional coral-like structures with dense porosity and high of Fe–N species content. As a heterogeneous Fenton catalyst of the methylene blue (MB) degradation, the prepared composite showed impressive activity over a wide pH range (4–10). Almost 100% of the MB could be degraded in 60 min, and the results agreed well with the pseudo-first-order kinetic model. To identify the crucial active sites of MB degradation, the correlation between the rate constant derived from the pseudo-first-order kinetic model and the different Fe species in the catalyst prepared under various conditions was investigated. This revealed the key role of the Fe–N complexes for the heterogeneous Fenton reaction. Moreover, Fe-NGLC exhibited recyclability and only a slight decrease in removal efficiency after five cycles. The excellent performance of Fe-NGLC demonstrates its great potential as a Fenton catalyst for wastewater treatment.

Due to high specific surface and plentiful of porosity, 3D porous carbon matrix has shown enormous potential for catalyst supporters. Hydrogen was thought as the next-generation clean energy to substitute the fossil fuel. Metal phosphides has been investigated and exhibited a good catalytic performance for hydrogen evolution reaction (HER). In this work, we prepared Ni2P/CoP loading on Porous carbon matrix through a facile method. The mixture of nickel nitrate, cobalt nitrate and chitosan was ball-milled, then was carbonized under N2 atmosphere at 900°C with NH4HPO2. The as-obtained materials were characterized by X-Ray diffraction (XRD), SEM and Raman spectrums. Also the electrochemical performance for HER was test using electrochemical workstation. The result shown that this catalysts presented a low overpotential at 10 mA cm-2, which was 270 mV.

Carbon aerogels with low cost and eco-friendly are considered as ideal electrode materials for supercapacitors. In this investigation, nitrogen self-doped carbon aerogels (NSCA) are prepared by microwave hydrothermal and high-temperature carbonization using chitin as carbon and nitrogen sources. Zinc chloride is used as a dehydration agent and an activator. Owing to the low boiling point of Zinc chloride, it does not require any additional steps to remove the activator. Also, due to the activation of Zinc chloride, the specific surface area of NSCA reaches 2540 m2 g−1. In the three-electrode system, NSCA-1000 exhibits specific capacitance of 249.4 and 164.9 F g−1 at current densities of 1.0 and 10 A g−1, respectively. In the two-electrode system, the NSCA-1000 based symmetrical supercapacitor demonstrates an energy density and power density of 26.15 Wh kg−1 and 0.95 kW kg−1 at 1.0 A g−1, respectively. Meanwhile, NSCA-1000 displays excellent cycling stability that the specific capacitance can maintain 98.44% after 15,000 cycles at a current density of 2.0 A g−1.

Wet gels (WGs) have been obtained from the polymerization of phloroglucinol (P), resorcinol (R) and formaldehyde (F) using sodium carbonate (C) as catalyst with kaolin (KL) addition. Carbon aerogels (CAs) have been gotten through the carbonization of WGs. The porous texture properties of as - prepared samples are investigated using the surface-area analyzer. The crystal structure of CAs are studied by X-ray diffraction (XRD) and the degree of graphitization are obtained through a Raman spectrometer. Meanwhile scanning electron microscopy (SEM) are executed to observe the morphology of different samples. When the addition of 5 wt%, the samples exhibit the high specific surface area (SSA), up to 855m2 g–1, with a concentrated pore size disdribution (PSD) of 30 nm.

In this article, Fe-doped carbon aerogels were prepared by one-step carbonization using sodium alginate as the raw material. The composition of the materials was characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results show that when the carbonization temperature is lower than 700 °C, iron mainly exists in the form of Fe3O4. When the carbonization temperature is higher than 700 °C, iron mainly exists in the form of Fe and CFe15.1.

Microporous carbon xerogels (CXs) were successfully fabricated via a facile one-pot strategy using eutectic salt mixture (KCl and ZnCl2) as dual activator and catalyst. Their pore structures, morphology, and selective CO2 adsorption behaviors were thoroughly studied by varying the contents of eutectic salt mixture. The presented CXs herein showed excellent CO2 adsorption selectivities, and the CX-4 with optimum salt concentration (12.9%) exhibited the highest CO2 adsorption capacity of 4.39 mmol g−1 at 273 K, which was ascribed to their special microscopic pore structure. Compared with the reported carbon materials, the optimum CX-4 exhibits a comparable or superior CO2 adsorption performance under similar conditions, showing great potential for efficient CO2 capture and separation from flue gas and natural gas.

In the present study, nanoscale rod-shaped manganese oxide (MnO) mixtures were successfully prepared from graphitic carbon nitride (C3N4) and potassium permanganate (KMnO4) through a hydrothermal method. The as-prepared MnO nanomixtures exhibited high activity in the adsorption and degradation of methylene blue (MB). The as-synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), surface area analysis, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Furthermore, the effects of the dose of MnO nanomixtures, pH of the solution, initial concentration of MB, and the temperature of MB removal in dye adsorption and degradation experiments was investigated. The degradation mechanism of MB upon treatment with MnO nanomixtures and H2O2 was studied and discussed. The results showed that a maximum adsorption capacity of 154 mg g&minus, 1 was obtained for a 60 mg L&minus, 1 MB solution at pH 9.0 and 25 &deg, C, and the highest MB degradation ratio reached 99.8% under the following optimum conditions: 50 mL of MB solution (20 mg L&minus, 1) at room temperature and pH &asymp, 8.0 with 7 mg of C, N-doped MnO and 0.5 mL of H2O2.

Environmental problems caused by metal ions have caused widespread concern in recent years. In this work, carbon aerogels (CAs) adsorbing different metal ions were prepared. The adsorption performance and kinetics of metal ions (Cu(II), Cr(VI), and Fe(III)) on carbon aerogels were systematically investigated. The results indicated that the maximum adsorption capacity of Cu(II) was 424 mg&middot, g&minus, 1 in 600 mg&middot, L&minus, 1 copper solution. Adsorption performances of Cu(II), Cr(VI), and Fe(III) on CAs well fitted with a pseudo-second-order kinetic model. The structures and morphologies of metal-containing samples were characterized by scanning electron micrographs (SEM), Energy Dispersive Spectrometer (EDS), transmission electron microscope (TEM), and X-ray diffraction (XRD). The results demonstrated that the texture and electrochemical performance of CAs adsorbing metal ions exhibited a clear change. The specific surface area of CAs for adsorbing copper ions was 450 m2&middot, 1 and they showed a small average pore diameter (7.16 nm). Furthermore, CAs adsorbing metals could be used for the super capacitor. The specific capacitance of CAs adsorbing copper ions could reach 255 F&middot, 1 at a current density of 1.0 A&middot, 1. The CA-Cu electrode materials exhibited excellent reversibility with a cycling efficiency of 97% after 5000 cycles.

Carbon aerogels with excellent conductive characteristics and high specific capacitance have attracted more and more interests for next-generation energy storage applications. Three-dimensional interconnected Mn

Carbon aerogels of an inter-connected three-dimensional (3D) structure are a potential carbon material for supercapacitors. We report a new oxidation modification method to prepare a series of modified carbon aerogels (OM-CA) by Hummers oxidation method. Oxidation-modified carbon aerogels (OM-CA) are obtained from carbon aerogel powders oxidized by Hummers method. Sulfuric acid stoichiometry is studied in order to investigate the effect of the surface oxygen group on surface area and electrochemical performance. Additionally, heteroatoms are doped into carbon aerogels in the oxidation process. The effect of heteroatom doping on electrochemical performance as a supercapacitor electrode material is investigated. When the amount of sulfuric acid is 40 wt%, the dopping manganese content is 0.9 mol%, the specific surface area of OM-CA is 450 m2/g, and its specific capacitance is 151 F g−1 at 0.5 A g−1, which is achieved by heteroatom doping and texture properties. In addition, OM-CA composite supercapacitors exhibit a stable cycle life at a current density of 0.5 A g−1 and retain 98.0% of initial capacitance over 500 cycles, and OM-CA-40% still presents a higher capacity, up to 148 F g−1 at 0.5 A g−1. The high specific surface area and specific capacitance suggest the porous carbon material has potential applications in supercapacitors.

An N-doped carbon/CuO-Fe2O3 (NC-CuFe) nanocomposite was successfully prepared via a simple, green one-pot annealing method. Different techniques were employed to characterize the physical and chemical properties of the prepared products, such as the composition, texture, structure and reducibility. XRD, XPS, TPR and especially TEM demonstrated the formation of CuFe2O4 in the Cu-doped composite. All the Cu-doped materials (NC-CuFe) showed higher activity in the Fenton reaction of MB degradation than the non-doped sample (C-Fe). In particular, the composite doped with 10 wt% CuO (NC-CuFe-2) exhibited the best performance, with approximately 98% of the methylene blue (MB) removed in 180 min in the presence of H2O2. The high specific surface area, the mutual charge interaction between Cu2+ and Fe3+, the mobility of the lattice oxygen and the high pyridinic N content in NC-CuFe-2 were responsible for the high activity in the Fenton reaction. Moreover, NC-CuFe-2 also demonstrated excellent stability and reusability, which were crucial for practical applications.

Carbon aerogels were prepared through a polycondensation of phloroglucinol, resorcinol and formaldehyde with sodium carbonate as the catalyst under different drying methods. The drying methods were room temperature drying, vacuum drying and freeze drying. The effects of different drying methods on the porous structure of carbon aerogels were studied systematically. The texture and pore structure were investigated under scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and a surface-area analyzer. The results show that the freeze-drying method was good for the specific surface area of carbon aerogels, up to 843 m2 g–1.

Polycondensation of phloroglucinol, resorcinol and formaldehyde with carbon nanotube (CNT) as the additives, using sodium carbonate as the catalyst, leads to the formation of CNT - doped carbon aerogels. The structure of carbon aerogels (CAs) with carbon nanotubes (CNTs) were characterized by X-ray diffraction and scanning electron microscopy. The specific surface area, pore size distribution and pore volume were measured by surface area analyzer. The results show that when the optimum doping dosage is 5%, the specific surface area of CNT - doped carbon aerogel is up to 665 m2 g-1 and exhibit plentiful mesoporous.

Ni-doped carbon aerogel was prepared by impregnation methods, physical structure, and electrochemical properties were investigated. Electrochemical properties of prepared Ni-doped carbon aerogel and carbon aerogel electrodes were measured by galvanostatic charge/discharge measurements. The results show Ni-doped carbon aerogels maintain the elementary structure of carbon aerogel, but they exhibited higher specific capacitance than carbon aerogel.

Large quantities of prism-shaped GaN nanorods were prepared by a thermal CVD reaction between Ga and NH3 on LaAlO3 crystal substrates. The distinct morphology of the GaN nanorods lies in their prism-like out shape and most of them have a quadrilateral cross section. The Raman spectrum of the GaN nanorods shows two additional bands at 255 and 419 cm(-1). Moreover, a large red shift of A(1)(LO) phonon has been observed compared with that of bulk GaN crystals. Room-temperature photoluminescence measurement reveals a broad emission ranging from 2.5 to 3.5 eV with some fine structures, which are believed to be associated with the defect levels.

Three kinds of GaN samples (hexagonal coarse-grain powders, hexagonal nanoparticles and cubic nanoparticles) were synthesized by different methods. The room-temperature frequency spectra of the relative dielectric constant and that of the dielectric loss were measured in the frequency range of 100 Hz to 10 MHz. Analysis of these spectra indicates that the grain size of samples has great influence on the dielectric behavior of samples whereas the crystallography symmetry almost has no impact on the relative dielectric constant.

This paper investigates the influence of the trailing edge flap on integrated loads and the flow field structure of wind turbine blades. The dynamic trailing edge flap under sinusoidal wind velocity is simulated using three-dimensional computational fluid dynamics method, and SST k-ω turbulence model coupled with γ-Reθ transition model is adopted to model the turbulence. The results show that the variation of root flap bending moments can be reduced by up to 38%. A proper phase difference added to the flap deflection could improve the ability of loads reduction for some cases. The flap deflection impacts almost all sections of the blade, and the blade elements momentum method should be modified to obtain better results.