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Due to the poor microwave absorption ability of graphene oxide (GO), direct reduction of GO by solid-state microwave irradiation is inefficient. In this study, GO was reduced effectively by a hybrid microwave heating (HWH) method by using mildly reduced graphene oxide (MG) membrane as a external susceptor, in which MG was obtained by annealing of GO at 300 °C for 1 h under nitrogen by a conventional heating method. When the mass ratio of MG to GO is 0.045, the C/O atomic ratio of GO increases from 1.8 to 17.84 by microwave irradiation under argon at 2000 W for 30 s. However, when GO was irradiated solely under the same conditions, the ratio of C/O was unchanged (1.88). For comparison, the MG was further irradiated by microwave at 2000 W for 30 s, its C/O ratio is enhanced from 4.17 to 8.46, demonstrating the higher reduction efficiency due to a mixed heating mode in the HWH process. The conventional heating of GO occurs during the initial stage and a two-way heating mode during the later stage, in which MG heats the GO from the surface and the microwave heating from the GO itself. Therefore, more amount of carboxyls and epoxides can be removed in the HWH process to achieve higher C/O ratio compared with that of the product obtained by direct microwave irradiation of MG.

Poly-γ-glutamic acid (γ-PGA) is one of the few bacterial polymers in nature with high added value of biodegradability. Especially, the traditional method of extracting γ-PGA is organic solvent extraction, etc., which has the disadvantages of low extraction rate and serious environmental pollution. With the expansion of γ-PGA industrial fermentation, an efficient and environmentally friendly method is required to be adopted. In this contribution, we report a novel method of separation of γ-PGA from fermentation broth based on molecular imprinting technology. The molecular imprinted polymer (MIP) was synthesized from chitosan (CS) and glutaraldehyde in the presence of γ-PGA. A nonimprinted polymer (NIP) was also synthesized by the same procedure in the absence of γ-PGA. The chemical structures and morphological structures of both MIP and NIP were examined by FTIR spectroscopy and scanning electron microscopy. The adsorption isotherms showed that the maximum adsorption capacity of MIP was 137.85 mg/g. The maximum adsorption capacity in the adsorption of NIP was 68.92 mg/g, which indicates that MIP shows specific selectivity for γ-PGA. A high saturated absorption capacity (Qmax=140.90 mg/g) was calculated from Freundlich isotherm equation. The imprinting factor of MIP was 4.76, indicating that MIP possess good recognition ability and selectivity for γ-PGA. The adsorption capacity decreased slightly (17.0%), which suggests the satisfactory reusability of γ-PGA after 5 cycles of reuse. Our study indicates that molecularly imprinted polymers present development prospects in the effective and selective separation of γ-PGA from fermentation broth compared with organic solvent precipitation.

LiNi0.5Co0.2Mn0.3O2 (NCM 523) and LiNi0.8Co0.1Mn0.1O2 (NCM 811) cathode materials were synthesized via a solid state reaction routine. XRD investigation revealed a hexagonal layered structure without impurity phase for the two samples and significant increase in the diffraction intensity ratio of I (003)/I (104) were observed. SEM showed no obvious secondary particles size change, but the tiny primary particles of the NCM 811 sample were smaller than those of the NCM 523 sample. The electrochemical tests exhibited the different electrochemical behaviors for the two samples. The calculation of diffusion coefficients showed that the DLi+ values of the NCM 523 and NCM 811 electrodes were calculated to be 1.14 × 10−9 and 3.04 × 10−9 cm2/s, respectively, which indicated that Li-ion diffused faster in the NCM 811 electrode.

Alumina aerogels are prepared from the cheap AlCl3·6H2O precursor by the sol-gel method using acetoacetic-grafted polyvinyl alcohol (acac-PVA) as a template and dispersing agent, and propylene oxide as a gelation initiator. The acac-PVA has a high dispersing ability for Al3+ ion through complexation interaction and increases the content of AlCl3·6H2O in sols to as high as 37 wt%, leading to the formation of wet gels without precipitate and crack, and little shrinkage. As-prepared alumina aerogels have high density, high mechanical strength, high mesoporosity, and high-surface area. The shrinkage in supercritical drying processes is greatly reduced. The specific surface area increases and pore size decreases with increasing the content of the acac-PVA in sols. The acac-PVA also acts as a template that provides nucleation sites for boehmite AlOOH particles and inhibits their growth. An excess content of the acac-PVA isolates secondary particles, weakens the interaction between them, and therefore decreases the Young’s modulus. Coarsening is not alleviated obviously after removal of the acac-PVA by high-temperature treatment in air, and the fine primary particles grow into nanorods with diameters of 10–20 nm and lengths of 30–70 nm.

Cotton fabric/LiFePO4 cathode material was synthesized via a conventional solvothemal method. XRD results revealed that all the patterns could be indexed as the olivine-type structured LiFePO4 with the space group of Pnma. SEM images showed that the obtained samples presented plate-type morphology. When the cotton fabric (soaked in the 0.1 M LiOH solutions)/LiFePO4 used as the cathode material for lithium-ion battery, it showed excellent cycle stability, i.e., an extremely low loss in the capacity of 7.8% after 200 cycles at 2 C, due to the enhanced electronic conductivity and Li-ion diffusion processes as also proved by the electrochemical impedance spectroscopy (EIS). Thus, this low cost cotton fabric decorated LiFePO4 composite is a promising cathode material for high-performance lithium-ion battery.

The pre-oxidized fibers were carbonized at the temperature ranging from 400 to 1300 °C for 1 h. The microwave absorption properties of carbon fibers (CFs) were examined in the frequency range of 2–...

Al 2 O 3 -C hybrid aerogels were prepared by a one-pot sol-gel method, supercritical n-hexane drying and carbonization using Al(NO 3 ) 3 ·9H 2 O as the Al 2 O 3 source, resorcinol (R) and furfural (F) as carbon precursors, and propylene oxide (PO) as a gelation initiator. The effects of the Al 2 O 3 contents, the R+F concentrations and the PO/Al molar ratios on the porosity of the hybrid aerogels were investigated using a constant R/F molar ratio of 0.5. It was found that the hybrid aerogels are all mesoporous with an average pore size below 20 nm. The crystalline structure of Al 2 O 3 is γ -type, but its diffraction peaks are quite broad. The hybrid aerogels are monolithic when the Al 2 O 3 content is below 5.31 wt% with an R+F concentration of 10 g/100 mL. The mesopore volume and size, BET surface area and external surface area all increase with increasing PO/Al molar ratio under otherwise identical conditions. The volume shrinkage decreases, carbonization yield increases and the density of the hybrid aerogel exhibits a maximum with an Al 2 O 3 content of 4.93 wt%. The size and volume of the mesopores, and the external surface area decrease with the increasing R+F concentration at PO/Al ratios of 5 and 6, but increase with increasing R+F concentration at a PO/Al ratio of 4.

The reactive adsorption desulfurization behavior of the Ni and Zn metal species supported on the activated carbon were investigated. The adsorbents were prepared by incipient wetness impregnation of the carbon support with aqueous solutions of nickel nitrate, zinc nitrate and nitrilotriacetic acid. The impregnated precursors transfer to ZnO and Ni3ZnC0.7 phase after calcination in nitrogen, and partially convert to NiZn alloy by hydrogen reduction treatment. The residual Ni3ZnC0.7 phase of the reduced adsorbents can be consumed slowly in the desulfurization process. The sulfur content of outflow oil can be readily decreased from original 640 ppmw to near zero residual sulfur with a breakthrough sulfur capacity of 106.5 mg-S/g-adsorbent, corresponding to 490 mg-S/g-(NiO + ZnO). The high efficiency of the adsorbents suggests that the release of metallic Ni from NiZn alloy is sufficiently rapid to provide an active phase for desulfurization and the formation of NiZn alloy is also favorable for the contact between Ni and Zn species which could accelerate the sulfur transfer from Ni3S2 to Zn phase.

The ordered mesoporous carbon-silica-alumina nanocomposites (MCSAs) with different ratios of Si/Al (10, 20 and 100) were synthesized by a multi-component co-assembly method followed by pyrolysis at high temperatures. The Si/Al ratio has an important effect on the acidic characteristics of the nanocomposite. The pyridine FT-IR results show that the nanocomposite with a Si/Al ratio of 100 has maximum amount of Bronsted acid sites. This may be because more non-framework Al-O-Si species are generated in the MCSA samples with lower Si/Al ratio due to the dealumination of the precursor in an acidic media during the surfactant-based assembly procedure and/or partial dealumination occurring during high temperature calcination. The copper-modified MCSAs were prepared by incipient wetness impregnation followed by calcination. The desulfurization performance of the as-prepared adsorbents was evaluated by the selective adsorption of dibenzothiophene (DBT) as a model sulfur compound from model fuels at ambient conditions. The dispersion extent of copper species increases with the increase of Bronsted acid sites, which results in a higher selectivity for DBT in competition with benzene. Compared with our previously prepared ordered mesoporous carbon-silica nanocomposite (MCS), the promotion effect of aluminum incorporation on the desulfurization selectivity is demonstrated. Moreover, the ordered mesoporous carbon-alumina nanocomposite (MCA) was also prepared. Its ordered mesostructure partially collapsed and the micropore volume is increased after copper incorporation, resulting in a good enhancement in sulfur capacity and selectivity.

Novel Mn&ndash, Ce&ndash, Ti&ndash, O composite aerogels with large mesopore size were prepared via a one-pot sol&ndash, gel method by using propylene oxide as a network gel inducer and ethyl acetoacetate as a complexing agent. The effect of calcination temperature (400, 500, 600, and 700 &deg, C) on the NH3&ndash, selective catalytic reduction (SCR) performance of the obtained Mn&ndash, O composite aerogels was investigated. The results show that the Mn&ndash, O catalyst calcined at 600 &deg, C exhibits the highest NH3&ndash, SCR activity and lowest apparent activation energy due to its most abundant Lewis acid sites and best reducibility. The NO conversion of the MCTO-600 catalyst maintains 100% at 200 &deg, C in the presence of 100 ppm SO2, showing the superior resistance to SO2 poisoning as compared with the MnOx&ndash, CeO2&ndash, TiO2 catalysts reported the literature. This should be mainly attributed to its large mesopore sizes with an average pore size of 32 nm and abundant Lewis acid sites. The former fact facilitates the decomposition of NH4HSO4, and the latter fact reduces vapor pressure of NH3. The NH3&ndash, SCR process on the MCTO-600 catalyst follows both the Eley&ndash, Rideal (E&ndash, R) mechanism and the Langmuir&ndash, Hinshelwood (L&ndash, H) mechanism.

A series of H3PW12O40 (HPW)-modified Fe2O3 catalysts for the selective catalytic reduction of NOx by NH3 (NH3-SCR) were synthesized via impregnation of HPW on Fe2O3 micro-flowers followed calcination. The optimum HPW/Fe2O3-350-0.5 catalyst exhibits nearly 100% of NO conversion at 240–460 °C as well as excellent SO2 resistance. The number of Bronsted acid sites and Lewis acid sites increases significantly after HPW modification, which promotes the adsorption of NH3. Moreover, the incorporation of HPW decreases the oxidation ability of Fe2O3 catalysts, which effectively inhibits the overoxidization of NH3, resulting in excellent catalytic activity and N2 selectivity. In-situ DRIFTS results indicate that the NH3-SCR reaction on HPW/Fe2O3-350-0.5 catalyst mainly follows Eley–Rideal (E-R) mechanism, in addition, the adsorption and oxidization of SO2 on the surface of HPW/Fe2O3-350-0.5 catalyst are suppressed due to high surface acidity and the decrease of oxidation ability, leading to the enhancement of SO2 tolerance of HPW-modified Fe2O3 catalysts.

To cope the challenges of poor conductivity and volume change for iron oxide, sandwich-like reduced graphene oxide/Fe2O3/N-doped carbon nanosheets are well designed and constructed via a two-step process through the combination of graphene-oriented hydrothermal method and the sol–gel coating technology. Nanometer Fe2O3 with a size of 10 nm is anchored within the sandwich structure composed of graphene nanosheet and a thin nitrogen doping carbon layer. Such unique structure can not only reduce the length of pathway for lithium ion diffusion and electron transport but also greatly alleviate the volume expansion as well as offer more surface active sites for electrochemical process, leading to a superior cycle stability and a high rate capability. The obtained nanosheet delivers an outstanding lithium storage capacity of 1116.7 mA h g−1 after 100 cycles at current density of 500 mA g−1 and an excellent rate capability of 547.4 mA h g−1 at high current density of 4 A g−1. Furthermore, full cell is fabricated using the nanosheet as anode and commercial LiFePO4 as cathode, which exhibits stable cycling performance, indicating good applicability of the anode. This work proposes a novel strategy to synthesize composites which could be further applied to the development of transition metal oxides and carbon composites as anode for lithium ion batteries.

In this work, the graphite nanoplatelets/carbon composites were fabricated from graphite nanoplatelets and pitch powders by a hot-pressing technology followed by carbonization and graphitization. The XRD and pole figure results show that the incorporation of pitch induces the decrease of size (La) and orientation degree of graphitic crystallites, while the in-plane thermal conductivity of graphitized sample is increased with the increasing pitch content up to 6 wt.%, achieving a maximum value of 405 W/m K. The pitch binders are filled into the voids to bridge two or more graphite nanoplatelets particles together to form extra thermal paths, which makes a great contribution to the enhancement of thermal conductivity. A thermal conductivity model for the graphitized composites is constructed based on a bridging mechanism, and the predicted results fit well with the experimental results.

The influence of the oxidation degree of graphene oxide (GO) on its deoxygenation efficiency via hybrid microwave heating (HWH) method by using graphite powder as the external susceptor was investigated, and the response behavior was compared with the situation when GO is directly submitted to microwave irradiation. In addition, the deoxygenation behavior of mildly reduced GO (VRGO) that was obtained via chemical reduction by Vitamin C was compared with that of GO during above two microwave heating processes. No response of GO to microwave irradiation when GO samples are exposed directly to microwave, no matter how the oxidation degree is. However, the VRGO sample can be heated when it is solely submitted to microwave irradiation. The partial reduction of GO leads to enhancement of the dielectric parameters, and the residual defects and oxygen-containing functional groups not only can improve the impedance matching characteristics, but also produce defects polarization relaxation and dipole polarization relaxation, which are all beneficial to the microwave penetration and absorption. The deoxygenation efficiency of VRGO is lower in comparison with GO under the HWH condition, which should be attributed to higher amount of epoxides in GO samples that can be easily reduced in a mixed heating mode.

TiO2/C nanospheres with diameter of 300–400 nm were synthesized by controlled thermal decomposition of titanium glycolate spheres in inert atmosphere. The effect of the calcination temperature and atmosphere on the structure and composition of the product are investigated. The products obtained by calcination of the precursor in nitrogen at 500°C consist of anatase and rutile nanoparticles, and amorphous carbon that is in situ generated from the organic components of glycolate precursor. When used as anode material for lithium-ion batteries, the as-prepared TiO2/C nanocomposite delivers a capacity of 166 mAh/g after 250 charge/discharge cycles at a current rate of 0.2 C and give a good rate capability. The native carbon not only improves the local conductivity but also prevents the aggregation and growth of TiO2 nanoparticles during calcination, allowing efficient electronic conductivity and Li ion diffusion.

The effects of various Ti concentrations doping on the electrochemical properties of LiNi0.8Co0.1Mn0.1O2 (NCM 811) sample were systematically studied. The XRD, EDS and XPS analyses indicated that the Ti-ion was substituted the occupied sites of Li and transition metal on the crystal structure. It also led to the increase of lithium interlayer spacing and the decrease of transition metal interlayer slab. The secondary particle size distribution of the 0.005 mol Ti-doped in LiNi0.8Co0.1Mn0.1O2 approximated to normal distribution. It showed multi-layer performance with high capacity (214.9 mAh g−1 at 0.1C), good rate performance (165.02 mAh g−1 at 1 C, 136.9 mAh g−1 at 5 C) and more excellent cyclic stability (77.01% after 150 t h at 1 C and 86.54% after 50 t h at 5 C). TEM studies revealed that the structural degradation on NCM 811 primary nano-particle could be effectively suppressed by the effect of Ti ions doped. The results demonstrated that doping of Ti content had superior advantages for LiNi0.8Co0.1Mn0.1O2 cathodes.

The deoxygenation efficiency of graphene oxide (GO) under solid-state microwave irradiation was improved via chemical pre-reduction using different reductants (Vitamin C, hydrazine hydrate and sodium borohydride). The reduced graphene oxide (RGO) samples obtained by reduction of GO via Vitamin C were denoted as VRGO-x (x = 0.33, 1.5 and 5), where x indicates the mass ratio of VC to GO (RVC/GO). And the products fabricated via reduction of GO by hydrazine hydrate and sodium borohydride are recorded as HRGO and SRGO, respectively. It is found that deoxygenation efficiency of RGO samples at the similar initial oxygen concentrations via further microwave irradiation is different. For instance, the oxygen concentration of VRGO-0.33 and SRGO decreases to 10.75% and 19.19%, and the oxygen concentration of VRGO-5 and HRGO decreases to 10.66% and 13.78%, respectively. The real part of complex permittivity (e′) of GO increases from 2.25 to 2.4–2.5 and 2.7–2.8 for VRGO-0.33 and SRGO, VRGO-5 and HRGO, demonstrating the absorption ability of VRGO-0.33 and SRGO, VRGO-5 and HRGO is very close, respectively. Compared with SRGO, the deoxygenation efficiency is higher for VRGO-0.33 that with higher content of carbonyls. This can be explained by that the lower energy is required to remove carbonyls relative to that for the other functional groups. Moreover, because HRGO contains high content of stable oxygen functional groups and some amount of nitrogen-containing groups, which are relatively stable at high temperature, especially for pyrrolic N and graphitic N, the reduction efficiency of HRGO is lower than that of VRGO-5.

Four activated carbons (ACs) activated by different activation methods from different precursors were heat-treated at 600℃ to decrease surface oxygen functional groups and to separate the effect of pore texture from surface chemistry on their sulfur adsorption performance. The ACs and the heat-treated ones were used as adsorbents for thiophene (T), dibenzothiophene (DBT), and 4,6-dimethyl dibenzothiophene (4,6-DMDBT) for model fuels with or without a competing benzene. The correlations of surface functional groups and pore textures to their adsorption capacities for T, DBT and 4,6-DMDBT were investigated. Results indicated that the heat treatment not only decreased surface oxygen content, but also caused a pore texture modification. The adsorption isotherms can be well fitted by the Langmuir–Freundlich single solute isotherm. The sulfur adsorption capacity of ACs after the treatment for T, DBT, and 4,6-DMDBT has a good linear relationship with the pore volume of pores within 0.536–1.090, 0.536–1.179, and 0.679–1.268 nm, respectively. The decreased percentage of surface oxygen of ACs by the heat treatment is correlated linearly with the decreased percentage of the sulfur adsorption capacity for all the thiophenic compounds. Micropore filling via the π–π interaction is the dominant adsorption mechanism of thiophenic compounds for both the untreated and heat-treated ACs. Surface oxides contribute to the thiophenic adsorption by a cooperative interaction of the π–π interaction and the acid–base interaction between the basic sulfur atom and the acidic carbon atoms linked with oxygen in graphene edges. A flat adsorption is the most possible geometry in the adsorption of thiophenic compounds.