Search

Carbon quantum dots (CDs) have attracted increased attention in recent decades because of their various applications in biosensing, bioimaging and drug delivery. In the present study, we have synthesized bifunctional ibuprofen-based carbon quantum dots (ICDs) using a simple one-step microwave-assisted method, for simultaneous bioimaging and anti-inflammatory effects. The ICDs exhibited high stability, low toxicity, negligible cytotoxicity and good biocompatibility in water. In particular, the produced ICDs demonstrated a decent imaging ability and excellent anti-inflammatory effects in vivo, making them potentially useful in bioimaging and future clinical treatment. Our results demonstrated that ICDs show promise in applications such as multifunctional biomaterials, depending on the selection of carbon sources, which would provide important guidance for the future design of multifunctional CDs in the field of biomedicine. [ABSTRACT FROM AUTHOR]

We propose general principles to construct two-dimensional (2D) single-atom-thick carbon allotropes. They can be viewed as the generalization of patterning Stone–Walse defects (SWDs) by manipulating bond rotation and of patterning inverse SWDs by adding (or removing) carbon pairs on the pristine graphene, respectively. With these principles, numerous 2D allotropes of carbon can be systematically constructed. Using 20 constructed 2D allotropes as prototypical and benchmark examples, besides nicely reproducing all well-known ones, such as pentaheptites, T-graphene, OPGs, etc, we still discover 13 new allotropes. Their structural, thermodynamic, dynamical, and electronic properties are calculated by means of first-principles calculations. All these allotropes are metastable in energy compared with that of graphene and, except for OPG-A and C3-10-H allotropes, the other phonon spectra of 18 selected allotropes are dynamically stable. In particular, the proposed C3-11 allotrope is energetically favorable than graphene when the temperature is increased up to 1043 K according to the derived free energies. The electronic band structures demonstrate that (i) the C3-8 allotrope is a semiconductor with an indirect DFT band gap of 1.04 eV, (ii) another unusual allotrope is C3-12 which exhibits a highly flat band just crossing the Fermi level, (iii) four allotropes are Dirac semimetals with the appearance of Dirac cones at the Fermi level in the lattices without hexagonal symmetry, and (vi) without the spin–orbit coupling (SOC) effect, the hexagonal C3-11 allotrope exhibits two Dirac cones at K and K′ points in its Brillouin zone in similarity with graphene. [ABSTRACT FROM AUTHOR]

Using Zn(NO3)2, H2SeO3 and graphene oxide as precursors, the zinc oxide/selenium/reduced graphene oxide (ZnO/Se/RGO) composite was facilely electrodeposited on the surface of indium tin oxide glass. The conditions for electrochemical synthesis such as electrodeposition potential and electrolyte composition were studied. The morphology and crystallization of the products as-prepared were characterized using scanning electron microscopy (SEM) and x-ray diffractometry (XRD) respectively. The light absorption and conductivity of the products were studied by UV-visible spectroscopy (UV-vis) and electrochemical impedance spectroscopy (EIS). Based on a series of experimental results, the photoelectrical conversion mechanism and effect factors of the products were explored. By means of synergistic action of n-type ZnO, p-type Se and conductive RGO, the ZnO/Se/RGO composite showed excellent photoelectric conversion under visible light irradiation. [ABSTRACT FROM AUTHOR]

Oxidized asphaltene (OA), a thermosetting material with plenty of functional groups, is synthesized from asphaltene (A) using HNO3/H2SO4 as the oxidizing agent. Boron, nitrogen co-doped porous carbon (BNC—OA) is prepared by carbonization of the mixture of boric acid and OA at 1173 K in an argon atmosphere. X-ray photoelectron spectroscopy (XPS) characterization reveals that the BNC—OA has a nitrogen content of 3.26 at.% and a boron content of 1.31 at.%, while its oxidation-free counterpart (BNC—SA) has a nitrogen content of 1.61 at.% and a boron content of 3.02 at.%. The specific surface area and total pore volume of BNC—OA are 1103 m2·g−1 and 0.921 cm3·g−1, respectively. At a current density of 0.1 A·g−1, the specific capacitance of BNC–OA is 335 F·g−1 and the capacitance retention can still reach 83% at 1 A·g−1. The analysis shows that the superior electrochemical performance of the BNC—OA is attributed to the pseudocapacitance behavior of surface heteroatom functional groups and an abundant pore-structure. Boron, nitrogen co-doped porous carbon is a promising electrode material for supercapacitors. [ABSTRACT FROM AUTHOR]