Single-Layered Mesoporous Carbon Sandwiched Graphene Nanosheets for High Performance Ionic Liquid Supercapacitors

Ionic liquid based supercapacitors generally using nanoporous carbon as electrode materials hold promise for future energy storage devices with improved energy density, but their power performances are limited by the high viscosity and relatively large size of ionic liquid electrolytes. Understanding the relationship between the pore size of nanoporous carbon, the ionic liquid electrolyte diffusivity, and the energy/power density is critical for the development of ionic liquid based supercapacitors with high performance. Herein, we report the synthesis of single-layered mesoporous carbon sandwiched graphene nanosheets (sMC@G) with mesopore-dominant (82% ∼89%) high surface area and tunable mesopore sizes (4.7, 6.8, 9.4, 10.6, and 13.9 nm). When using 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF₄) as the electrolyte with a cation size of 0.76 nm, it is demonstrated that the ion diffusion coefficient increases a little when the mesopore size is not larger than 6.8 nm, and then jumps dramatically in the range 6.8–10.6 nm. When the pore size is enlarged to 13.9 nm, the ion diffusion coefficient increases slightly, approaching the bulk diffusion coefficient of the electrolyte. A size ratio of mesopore over electrolyte ion of 14 is recommended for fast ion/electrolyte transport and therefore improves the power density (14.7 kW kg^–1 at 20 A g^–1) without compromising the energy density (130 Wh kg^–1 at 1 A g^–1). The performance of sMC@G is superior to other porous carbon materials used in ionic liquid electrolyte supercapacitors

Dual-Functional Ultrafiltration Membrane for Simultaneous Removal of Multiple Pollutants with High Performance

Simultaneous removal of multiple pollutants from aqueous solution with less energy consumption is crucial in water purification. Here, a novel concept of dual-functional ultrafiltration (DFUF) membrane is demonstrated by entrapment of nanostructured adsorbents into the finger-like pores of ultrafiltration (UF) membrane rather than in the membrane matrix in previous reports of blend membranes, resulting in an exceptionally high active content and simultaneous removal of multiple pollutants from water due to the dual functions of rejection and adsorption. As a demonstration, hollow porous Zr­(OH)_<i>x</i> nanospheres (HPZNs) were immobilized in poly­(ether sulfone) (PES) UF membranes through polydopamine coating with a high content of 68.9 wt %. The decontamination capacity of DFUF membranes toward multiple model pollutants (colloidal gold, polyethylene glycol (PEG), Pb­(II)) was evaluated against a blend membrane. Compared to the blend membrane, the DFUF membranes showed 2.1-fold increase in the effective treatment volume for the treatment of Pb­(II) contaminated water from 100 ppb to below 10 ppb (WHO drinking water standard). Simultaneously, the DFUF membranes effectively removed the colloidal gold and PEG below instrument detection limit, however the blend membrane only achieved 97.6% and 96.8% rejection for colloidal gold and PEG, respectively. Moreover, the DFUF membranes showed negligible leakage of nanoadsorbents during testing; and the membrane can be easily regenerated and reused. This study sheds new light on the design of high performance multifunction membranes for drinking water purification

I dubbi sull’attuale rilevanza dei Gruppi di Imprese nel diritto del lavoro. Le oscillazioni della giurisprudenza e la necessità di un intervento organico del Legislatore in materia

Mesostructured hollow carbon nanoparticles have widespread applications. A big challenge in materials science is surfactant-free synthesis of hollow carbon nanoparticles with tunable mesostructures. Herein we report a new surfactant-free sequential heterogeneous nucleation pathway to prepare mesostructured hollow carbon nanoparticles. This strategy relies on two polymerizable systems, i.e., resorcinol formaldehyde and tetraethyl orthosilicate, each of which undergoes homogeneous nucleation and particle growth. By controlling the polymerization kinetics of two systems when mixed together, sequential heterogeneous nucleation can be programmed, leading to monodispersed and mesostructured hollow carbon nanoparticles with large mesopores, controllable mesostructures (bi- and triple-layered), and rich morphologies (invaginated, intact, and endoinvaginated spheres). For the first time, it is demonstrated that the invaginated structure shows better hemocompatibility compared to the intact one. The pristine hollow carbon nanoparticles with large pore size and high pore volume show the high loading capacity of biomolecules and successfully deliver biomolecules into cells. Our strategy has paved the way for the designed synthesis of unprecedented carbon nanostructures with potential applications in drug/biomolecule delivery