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CA-FSPCMs were constructed using a lightweight and high strength carbon aerogel to encapsulate PEG-6000, fabricated using biomass xanthan gum and polyimide.

Seagrass meadows are one of the most important marine ecosystems. Alkanes are the common hydrocarbon contaminants that can affect seagrass growth. In this study, a large spatial-scale investigation has been carried out on the alkane-degrading bacterial community structure in the rhizosphere and non-rhizosphere sediments of two seagrass species (Thalassia hemprichii and Halophila ovalis). AlkB gene was employed as a biomarker gene to study the alkane-degrading bacterial community structure. The results showed that the alpha diversity of the alkane-degrading bacterial community in T. hemprichii non-rhizosphere sediments was higher than that of its rhizosphere sediments. However, the alpha diversity of the alkane-degrading bacterial community in H. ovalis rhizosphere sediments was higher than that of its non-rhizosphere sediments in the open sea, but the result was contrast in the coast area. In addition, the alpha diversity of alkane-degrading bacterial communities in the coast area was higher than that of far away from the coast in the T. hemprichii rhizosphere and non-rhizosphere sediments. The phylogenetic analysis result revealed that the alkB sequences from the seagrass ecosystem were mainly affiliated with the class Alphaproteobacteria, and had the two novel lineages. Genus Agrobacterium was the most predominant alkane-degrading bacteria. These results contributed to disclose the geographical distribution pattern of alkane-degrading bacteria in the seagrass ecosystem of the South China Sea.

Advancements in inexpensive, efficient, and durable oxygen reduction catalysts is important for maintaining the sustainable development of fuel cells. Although doping carbon materials with transition metals or heteroatomic doping is inexpensive and enhances the electrocatalytic performance of the catalyst, because the charge distribution on its surface is adjusted, the development of a simple method for the synthesis of doped carbon materials remains challenging. Here, a non−precious−metal tris (Fe/N/F)−doped particulate porous carbon material (21P2−Fe1−850) was synthesized by employing a one−step process, using 2−methylimidazole, polytetrafluoroethylene, and FeCl3 as raw materials. The synthesized catalyst exhibited a good oxygen reduction reaction performance with a half−wave potential of 0.85 V in an alkaline medium (compared with 0.84 V of commercial Pt/C). Moreover, it had better stability and methanol resistance than Pt/C. This was mainly attributed to the effect of the tris (Fe/N/F)−doped carbon material on the morphology and chemical composition of the catalyst, thereby enhancing the catalyst’s oxygen reduction reaction properties. This work provides a versatile method for the gentle and rapid synthesis of highly electronegative heteroatoms and transition metal co−doped carbon materials.

As a renewable biomass and a low-cost crude carbon source, the ginkgo shell is explored for preparing high-value porous carbon via carbonization and the following KOH activation. Structure characterization shows that GSPC has microporous and mesoporous structure with specific surface area (SSA) of up to 1941 m2 g-1 , which exhibits superior capacitive properties. In a three-electrode system by using 6 M KOH as electrolyte, GSPC-700-1:2 could deliver a high specific capacitance of 345 F g-1 at 0.5 A g-1 . Even at a high current density of 20 A g-1 , the specific capacitance of as high as 280 F g-1 can be still maintained. Furthermore, a symmetric supercapacitor device (SCD) is fabricated by GSPC-700-1:2, which exhibits a capacitance retention rate of 83% at 5 A g-1 after 10000 charging/discharging cycles. A power density of 301 W kg-1 is achieved at an energy density of 13 W h kg-1 . The superior electrochemical performance demonstrates that ginkgo shell can function as a new biomass material for the production of porous carbon materials that are used in high-performance supercapacitors and other energy storage devices.

Oxygen reduction reaction (ORR) is a core reaction of fuel cell and metal-air cell. In recent years, it has been a hot topic to study non-precious metal catalysts for ORR. Herein, we have used waste wine mash-derived carbon, melamine and ferric chloride to prepare a Fe- and N- co-doped carbon catalyst. The specific surface area of the catalyst is up to 1066.6 m2 g−1. And its wave potential is 15 mV higher than that of commercial Pt/C catalyst. The ORR on our catalyst followed a four-electron pathway; and it has high stability and high impressive immunity to methanol. After continuous oxygen reduction of 30,000s, the retention rate is 90%.

Nitrogen and fluorine co-doped three-dimensional(3D) graphene-like material, MP-700, is successfully prepared using a one-pot method by directly pyrolyzing melamine and PTFE in N2 flow. This 3D graphene-like material has a high specific surface area (1309 m2 g−1) and the N and F contents are is 19.03 and 0.41 at.%, respectively. Furthermore, it shows the high specific capacitance of 230 F g−1 at 0.5 A g−1; and exhibits long-term stability. After 10,000 cycles, the capacitance retention rate is 86.3% at 20 A g−1, which has a good prospect in the electrode materials of supercapacitors.

Two-dimensional (2D) plasmonic oxides represent a new promising type of surface-enhanced Raman spectroscopy (SERS) substrate due to their atomic uniformity and high surface activities. However, current synthesis strategies of 2D structures are largely limited to intrinsically layered compounds, and nonlayered plasmonic oxides are not easy to synthesize as 2D materials, so the development of 2D nanoarchitecture based SERS substrates is seriously hindered. Here, we report a solid–solid surface reaction strategy for the fabrication of 2D nonlayered MoO2 nanosheets with an average thickness of 2–3 unit cells. By using these 2D MoO2 nanosheets as the SERS substrate to detect trace amounts of rhodamine 6G (R6G), the limit of detection concentration can be as low as 10−7 M and the maximum enhancement factor (EF) is up to 104. We anticipate that this strategy would provide beneficial insight for the fabrication of 2D non-layered nanoarchitectures, which would expand the family of 2D plasmonic materials.

Shape-stabilized phase-change composites (SSPCCs) have been widely applied for thermal energy storage and thermal management because of their excellent properties. To further improve their thermal conductivity and thermal cycling stability, we successfully designed and synthesized a series of SSPCCs with three-dimensional (3D) thermally conductive networks by exploiting the synergistic effect between one-dimensional (1D) carbon nanotubes (CNTs) and two-dimensional (2D) hexagonal boron nitride (h-BN). The interconnected thermally conductive network composed of h-BN and multiwalled carbon nanotubes (MWCNTs) enhanced the SSPCC performance. The micromorphologies of the prepared SSPCCs revealed that well-dispersed MWCNTs, hydroxylated h-BN, and polyethylene glycol (PEG) molecular chains effectively bonded into a 3D cross-linking structure of the SSPCCs. Moreover, the chemical and crystalline structural and thermal properties and thermal cycling stability of the novel SSPCCs were systematically investigated by various characterization techniques. The presence of a 3D thermally conductive network in the as-synthesized SSPCCs evidently improved the shape stability, phase-change behavior, and thermal stability. Benefiting from the 3D nanostructural uniqueness of SSPCCs, the thermal conductivity of SSPCC-2 was up to 1.15 W m-1 K-1, which represented a significant enhancement of 239.7% compared with that of pure PEG. Meanwhile, the efficient synergistic effect of h-BN and MWCNTs remarkably enhanced the heat-transfer rate of the SSPCCs. These results demonstrate that the prepared SSPCCs have potential for applications in thermal energy storage and thermal management systems. This study opens a new avenue toward the development of SSPCCs with good comprehensive properties.

As a promising non-precious metal photoelectrochemical (PEC) catalyst, MoS2 exhibits high electrocatalytic activity and stability, while the weak light absorption efficiency and low photoresponse current limit its practical application. Herein, a facile co-assembly approach is proposed to construct porphyrin-MoS2 composite photoelectrocatalysts. The as-prepared photoelectrocatalysts show a significantly enhanced photocurrent response as high as 16 μA cm-2 , which is about 2 times higher than that of bare MoS2 . Furthermore, the obtained porphyrin-MoS2 catalysts exhibit excellent durability when tested for 23000 s, thus providing a useful strategy for the design of highly efficient dye-sensitized PEC catalysts.

In this study, novel poly (ethylene glycol)/graphene oxide (PEG/GO) composite phase-change fibers (PCFs) were developed by using PEG as the phase change ingredient, GO as the thermally conductive filler, and PVP as the fiber matrix through electrospinning to enhance the thermal properties of shape-stabilized PCFs. Results indicated that PEG was grafted with GO by self-assembly among the functional groups. PVP was dispersed in the mixture to ensure nano-fiber formation. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images revealed that the diameters of the composite PCFs decreased due to GO addition. The addition amount of GO is 0.5 wt% can prepare the composite PCFs with a homogeneous and smooth surface. DSC results demonstrated that the composite PCMs possess good phase-change behavior, fast thermal-response rates, and excellent thermal reliability. The largest melting/crystallization enthalpy of the prepared composite PCFs with 0.5 wt% GO addition was 103.6 J g−1 and 101.1 J g−1. More importantly, after 100 DSC thermal cycles, there was no obvious change for phase-change enthalpy. The thermal conductivity of the composite PCFs can reach 0.5668 W/(m·K), indicating the thermal conductivity of composite PCFs increased significantly with the GO addition. Moreover, the composite PCFs possess excellent thermal-regulated performance, leakage resistance, and shape stability. Hence, the fabricated composite PCFs possess good comprehensive properties that can be used widely in thermo-regulated systems.

Introducing anion vacancies on two-dimensional transition-metal dichalcogenides (TMDs) would significantly improve their catalytic activity. In this work, we proposed a solid-phase reduction (SPR) strategy to simultaneously achieve efficient exfoliation and controlled generation of chalcogen vacancies on TMDs. Consecutive sulfur vacancies were successfully created on the basal plane of the bulk MoS2 and WS2, and their interlamellar distances were distinctly expanded after the SPR treatment (about 16%), which can be conveniently exfoliated by only gentle shaking. The S-vacancy significantly increases the hydrogen-evolution reaction activity of the MoS2 and WS2 nanosheets, with overpotential of -238 and -241 mV at 10 mA cm-2, respectively. We anticipate that our SPR strategy will supply a general platform for the development of TMD-based electrocatalysts for industrial water splitting and hydrogen production in the near future.

n-Octadecane/novel porous carbon composite phase-change materials (PCMs) containing a novel porous carbon as the supporting material for n-octadecane were successfully fabricated by vacuum impregnation. The novel porous carbon was first prepared using functionalized polystyrene nanoparticles as a template and soluble starch as a carbon source. The porous carbon spheres can adsorb n-octadecane, preventing them from leaking during the phase-change procedure, and providing them with high thermal conductivity as well as good mechanical and thermal stability. Results show that the novel porous carbon possesses a multi-porous and regular spherical structure with a specific surface area of 1100 cm2/g. Fourier-transform infrared spectroscopy and scanning-electron-microscopy images prove that n-octadecane/novel porous carbon composite PCMs were successfully prepared and exhibited a regular spherical profile. Differential scanning calorimetry reveals that the composite PCMs have an excellent energy storage property, and the latent heat can reach 170.5 J/g, which is higher than the theoretical value. Furthermore, the composite PCMs exhibited an outstanding thermal stability after 100 repeated thermal cycles, and the thermal conductivity were improved up to 0.631 W/(m∙K), which enhanced by 266% compared with n-octadecane. The composite PCMs also displayed a good shape stability without any leakage during heating at 40 °C. These results confirm that the composite PCMs are promising for thermal energy-storage application systems.

As a promising non-precious metal photoelectrochemical (PEC) catalyst, MoS