Le regole del gioco: Primo incontro con l'ingegneria strategica

Cu particles decorated carbon composite microspheres (CCMs) with a unique sesame ball structure have been prepared by combining the mass-producible spray drying technique with calcinations. The conventional cuprammonium cellulose complex solution obtained by dissolving cellulose in a cuprammonia solution has been applied as raw materials for the preparation of Cu­(NH₃)₄²⁺/cellulose complex microspheres via a spray drying process. The resulted Cu­(NH₃)₄²⁺/cellulose complex microspheres are then transformed into the Cu particles homogeneously decorated porous carbon spheres <i>in situ</i> by calcinations at 450 or 550 °C. The coordination effect between the Cu­(NH₃)₄²⁺ species and the hydroxyl groups of the cellulose macromolecules has been exploited for directing the dispersion of the Cu particles in the resultant composite CCMs. The antimicrobial effects of the CCMs are evaluated by determining the minimum growth inhibitory concentrations using Staphylococcus aureus and Escherichia coli as representatives, respectively. The CCMs show high efficiency catalytic properties to the conversion of 4-nitrophenol to 4-aminophenol using NaBH₄ as a reductant in a mild condition. The recyclability and stability of the CCM catalysts have also been studied

Electrochemical and Theoretical Study of π–π Stacking Interactions between Graphitic Surfaces and Pyrene Derivatives

In this study, the reversibility of π–π stacking interactions at graphite electrodes (GE) of pyrene, 1-aminopyrene, 1-pyrenecarboxylic acid, and doxorubicin hydrochloride (DOX) have been studied. The adsorption and desorption of these π-orbital-rich molecules was characterized using X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). The experimental investigations were complemented with a density functional theory study of the interaction between these π-orbital-rich molecules and graphite. It was demonstrated that the charged pyrene derivatives could be electrochemically desorbed from the graphitic surfaces, when a sufficiently high potential of the same charge as the pyrene derivative, was applied to the electrode. The duration of the applied potential, the pH and the magnitude of the applied potential during potential pulsing were found to be important with regards to the desorption efficiency. Up to 90% of charged pyrene derivatives could be removed from the electrode surface within 60 s via potential pulsing. However, these parameters produced insignificant effects on neutral pyrene bound to the graphite. A potential application of this electrochemically induced desorption of π-rich species in drug delivery was demonstrated via the release of adsorbed doxorubicin (DOX)

Spray-Drying-Induced Assembly of Skeleton-Structured SnO₂/Graphene Composite Spheres as Superior Anode Materials for High-Performance Lithium-Ion Batteries

Three-dimensional skeleton-structured assemblies of graphene sheets decorated with SnO₂ nanocrystals are fabricated via a facile and large-scalable spray-drying-induced assembly process with commercial graphene oxide and SnO₂ sol as precursors. The influences of different parameters on the morphology, composition, structure, and electrochemical performances of the skeleton-structured SnO₂/graphene composite spheres are studied by XRD, TGA, SEM, TEM, Raman spectroscopy, and N₂ adsorption–desorption techniques. Electrochemical properties of the composite spheres as the anode electrode for lithium-ion batteries are evaluated. After 120 cycles under a current density of 100 mA g^–1, the skeleton-structured SnO₂/graphene spheres still display a specific discharge capacity of 1140 mAh g^–1. It is roughly 9.5 times larger than that of bare SnO₂ clusters. It could still retain a stable specific capacity of 775 mAh g^–1 after 50 cycles under a high current density of 2000 mA g^–1, exhibiting extraordinary rate ability. The superconductivity of the graphene skeleton provides the pathway for electron transportation. The large pore volume deduced from the skeleton structure of the SnO₂/graphene composite spheres increases the penetration of electrolyte and the diffusion of lithium ions and also significantly enhances the structural integrity by acting as a mechanical buffer