Catalytic graphitization assisted synthesis of Fe3C/Fe/graphitic carbon with advanced pseudocapacitance.

We report an environmentally friendly strategy for the synthesis of Fe3C/Fe/graphitic carbon based on hydrothermal carbonization and graphitization of carbon spheres with potassium ferrate (K2FeO4) at 800 °C. The obtained sample consisting of Fe3C/Fe nanoparticles and graphitic carbon (FC-1-8) delivered an enhanced pseudocapacitance of 428.0 F g-1 at a current density of 1 A g-1. After removal of the Fe3C/Fe electroactive materials, the graphitic carbon (FC-1-8-HCl) possessed a large specific surface area (SSA) up to 2813.6 m2 g-1 with a capacity of 243.3 F g-1 at 1 A g-1, far outweighing the other amorphous carbon electrodes of FC-0-8 (carbon spheres annealed at 800 °C without the treatment of K2FeO4). The graphitic material with a porous structure could offer more electroactive sites and improved conductivity of the sample. This method provided guidelines for the synthesis of superior performance supercapacitors with synchronous graphitic carbon and electroactive species.

Eu3+-doped layered gadolinium hydroxides as drug carriers and their bactericidal behavior.

Layered rare earth hydroxides (LRHs) due to outstanding photoluminescence (PL) properties and anion exchangeability are extensively reported in multiple fields. In this work, the drug-loaded and bactericidal behaviors of Eu3+-doped layered gadolinium hydroxides (LGdHs:Eu) as optical carriers were explored through intercalation and release of cephalexin (CE). In the intercalation state, the PL intensity of CE--LGdHs:Eu obviously decreased because of the quenching effect of CE-. And the PL intensity of LGdHs:Eu was restored with the release of CE- ions in phosphate buffer solutions (PBS). A significant functional relationship between the drug releasing amount and PL intensity ratio was found, providing a novel optical method to specify the drug dosage. And CE--LGdHs:Eu showed the excellent bactericidal properties in both in vivo and in vitro experiments.

Soft-chemistry synthesis, solubility and interlayer spacing of carbon nano-onions.

Carbon nano-onions (CNOs), as one of the allotropes of carbon, have attracted great attention because of their excellent performance in many fields, especially in capacitors. Developing soft-chemistry synthesis methods is critically of importance, while the forming mechanism in this area is not clear. In this paper, we present a critical review of CNOs regarding the structure, especially interlayer spacing, and synthesis processes, elaborating the recent progress on soft-chemistry methods. Hansen solubility parameter theory is applied to predict and regulate the solubility of CNOs. This article would be inspirational and give new insights into understanding the formation and properties of CNOs.

Enhanced photoluminescence of LEuH nanosheets: 2D photonic crystals self-assembled by core-shell SiO2@LEuH spheres.

The enhancement in photoluminescence (PL) is a challenge for layered rare-earth hydroxides, which usually have weak PL due to the quenching effect of hydroxyls. In this work, we provide a strategy to enhance the PL behavior by constructing two-dimensional (2D) photonic crystals. The core-shell structured SiO2@LEuH spheres were prepared by attaching the positively charged layered europium hydroxide (LEuH) nanosheets onto the negatively charged surfaces of the SiO2 spheres; the core-shell spheres further formed a monolayered 2D colloidal crystal with the hexagonal lattice on a quartz substrate through an evaporation-induced assembly process. The 2D colloidal crystals exhibited a significantly enhanced photoluminescence at 611 nm related to the 5D0 → 7F2 transition of Eu3+ compared with the SiO2@LEuH spheres and the LEuH nanosheets dispersed in deionized water. The emission band of Eu3+ hardly changed in the three samples; therefore, the PL enhancement can be attributed to the emission band located at the short edge of the photonic band-gap of the 2D crystals.