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Charge mobility is an essential factor of organic crystalline materials. Although many investigators have made important progress, the exact relationship between the crystal structure and carrier mobility remains to be clarified. Fortunately, a series of bis-1,3,4-oxadiazole derivatives have been successfully prepared and reported. They have similar main molecular fragments but different crystal packing modes, which provide an ideal research objective for studying the effect of molecular packing on charge mobility in organic photoelectric conversion systems. In this work, the charge mobilities of these molecules are systematically evaluated from the perspective of first-principles calculation, and the effect of a molecular overlap on orbital overlap integral and final charge carrier mobility is fully discussed. It can be seen that the small intermolecular distance (less than 6 Å) is the decisive factor to achieve high electron mobility in π stacking, and better mobility can be obtained by increasing the hole migration distance appropriately. A larger dihedral angle of anisotropy is an important point limiting the charge mobility in the herringbone arrangement. It is hoped that the correlation results between the crystal structure and mobility can assist the experimental study and provide an effective way to improve the photoelectric conversion efficiency of the organic semiconductor devices and multiple basis for multiscale material system characterization and material information.

Nickel-organic framework (NiOF) compound with layered structure was prepared by solvothermal synthesis using nickel chloride and bezenedicarboxylic acid precursors. NiOF could be converted into nickel with a face-centered cubic structure and nickel oxide with a cubic rock-salt crystal structure after heating above 425 °C in air atmosphere. The organic units played a key role in the formation of well-dispersed nickel/nickel oxide nanoparticles. Primary particle size could be decreased by lowering the calcination temperature. Electrophoresis allowed for depositing a thin layer of nickel/nickel oxide nanoparticles on the skeleton of macroporous nickel foam (NF) as a catalyst electrode for electrooxidation of urea. Nickel/nickel oxide nanoparticles derived from NiOF at 425 °C possessed large amounts of redox active sites (Ni2+/Ni3+), and thus was capable of enhancing the current density and efficiency in urea electrolysis. NF substrate with unique macroporous conductive structure exhibited electrocatalytic behavior towards urea electrolysis and allowed for rapid transport of electron, electrolyte, and gaseous products. Therefore, coating of nickel/nickel oxide nanoparticles on NF provided a possible way for further enhancing the electrocatalytic ability of electrode in urea electrolysis, making it favorable for large-scale applications.

The eMCMBs (expanded mesocarbon microbeads) composed of fluffy graphene oxide nanosheets were obtained by chemical oxidation of MCMB graphite powder. The eMCMBs were attached to the skeleton of nickel foam through electrophoretic deposition. After heat treatment in reducing atmosphere, the eMCMBs were converted into reduced eMCMBs (reMCMBs) composed of sponge-like graphene nanosheets. Nickel foam with attached reMCMBs was used as a highly conductive scaffold to support nickel cobaltite nanoflakes. The sponge-like reMCMBs accommodated electrolyte solution, afforded current collector, and functioned as a stress buffer to alleviate electrode damage. Macroporous nickel cobaltite film with mesoporous thin nanoflakes could provide large amounts of pores for easy penetration of electrolyte solution, huge interfacial area for facile redox reactions, and short transport distance for ions and electrons. Nickel cobaltite grown around nickel foam with attached reMCMBs could deliver a high specific capacitance of 1025 F g −1 at 5 A g −1 , greater than that grown around nickel foam (688 F g −1 ). Nickel cobaltite nanoflakes grown on reMCMBs turned out to decrease the kinetic resistance, diffusive impedance, and volumetric strain, resulting in better capacitance, rate capability, and electrochemical stability.

A cyanide-bridged bimetallic coordination polymer, nickel hexacyanoferrate, could be pyrolyzed to form carbon-encapsulated nickel-iron (CE-NiFe) nanoparticles. The formation of nitrogen-doped spherical carbon shell with ordered mesoporous structure prevented the structural damage of catalyst cores and allowed the migration and diffusion of electrolyte into the hollow carbon spheres. An ultra-thin layer of CE-NiFe nanoparticles could be tightly attached to the three-dimensional macroporous nickel foam (NF) by electrophoretic deposition. The CE-NiFe nanoparticles could lower the onset potential and increase the current density in anodic urea electrolysis and cathodic hydrogen production as compared with bare NF. Macroporous NF substrate was very useful for the urea electrolysis and hydrogen production, which allowed for fast transport of electron, electrolyte, and gas products. The superior electrocatalytic ability of CE-NiFe/NF electrode in urea oxidation and water reduction made it favorable for versatile applications such as water treatment, hydrogen generation, and fuel cells.

Gelatin is an important hydrocolloid which has widespread applications in the pharmaceutical industry and biomedical science. However, despite its significance, clinical applications of gelatin are largely limited because of its gel-to-solution transition around human body temperature. In this work, we developed a series of F127–gelatin composite hydrogels with reverse thermo-responsive properties. The stiffness of F127–gelatin hydrogels can be adjusted by varying the types and contents of gelatin (type A, GA and type B, GB). The results of rheological data showed that F127–GA gels have higher gel strengths than those of F127–GB, which might be due to different isoelectric points between GA and GB. In addition, F127–gelatin gels showed significant cell viability and biocompatibility for human mesenchymal stem cells, indicating that these discovered hydrogels can serve as potential biomaterials and implantable scaffolds for applications in tissue engineering and regenerative medicine.

In this report, a simple and facile solvothermal method is developed for fabrication of platinum–ruthenium (PtRu) nanodendrites supported on reduced graphene oxide (PtRu-RGO) in the ethylene glycol (EG) system, using hexadecylpyridinium chloride (HDPC) as a shape-directing agent. The as-prepared nanocomposites show the superior catalytic activity and better stability towards EG oxidation, compared with RGO-supported Pt nanoparticles and commercial PtRu/C (Pt 30 wt. %, Ru 15 wt. %) catalysts. This strategy may open a new route to design and prepare advanced electrocatalysts in direct EG fuel cells.

In this work, a facile general strategy is developed for preparation of palladium-based bimetallic alloyed nanodendrites (PdM NDs, M = Pt, Co, and Ni) via coreduction of Pd(II) acetylacetonate and M(II/III) acetylacetonate salts with oleylamine. Hexadecylpyridinium chloride monohydrate (HDPC) is used as a co-surfactant for preventing the aggregation of nanodendrites. Control experiments varying the precursors and reaction time demonstrate that the dendritic nanocrystals are formed via aggregation-based crystal growth. The as-prepared hybrid nanocrystals display improved electrocatalytic activity and better stability for methanol and ethylene glycol (EG) oxidation, compared with home-made Pd NDs and commercial Pd black catalysts. The developed method provides a novel platform for synthesis of novel electrocatalysts in fuel cells.

Popcorn-like PtAu nanoparticles were fabricated by a facile and green one-pot wet-chemical method, where H2PtCl4 and HAuCl4 were simultaneously reduced by glucosamine in alkaline media. The PtAu nanoparticles were further supported on reduced graphene oxide by simple ultrasonication. The nanocomposites showed an enhanced catalytic performance toward oxygen reduction reaction (ORR), dominated by a four-electron pathway, in comparison with Pt–rGO and commercial 10% Pt/C catalysts. Meanwhile, the nanocomposites displayed improved electrocatalytic properties and better stability for methanol oxidation over Pt–rGO and commercial Pt/C catalysts.