Kinetics-controlled regulation for homogeneous nucleation and growth of colloidal polymer and carbon nanospheres.

Size regulation of uniform polymer nanospheres (PNSs) and carbon nanospheres (CNSs) below 100 nm has been difficult and is limited by multiple factors, such as ongoing nucleation, Ostwald ripening, minimization of surface energy, and high viscosity during the nucleation and growth process. In this study, a kinetics-controlled regulation is reported for the synthesis of monodispersed PNSs and corresponding CNSs with adjustable size below 100 nm. During the synthesis of PNSs, three distinct stages including surface energy control, surface tension control and viscosity control have been observed, where the concentration of block copolymer F127 (CF127) plays a vital role in affecting the nucleation rate of PNSs and tunes the diffusion rate of monomers and migration of particles during the nucleation and growth process. As a consequence, the size of monodisperse CNSs can be customized from 100 nm down to 41 nm with PDI below 5%.

Outside-in catalytic graphitization method for synthesis of dispersible and uniform graphitic porous carbon nanospheres.

Common strategies to synthesize graphitic porous carbon nanospheres suffer from energy consumption, exorbitant cost and harsh condition, and lead to closed pore and polydisperse particles. The successful manipulation of adjustable graphitic skeleton, developed porosity, good monodispersity and dispersity of carbon nanospheres is essential to meet their structural varieties and practical applications. Herein, an outside-in catalytic graphitization method is reported to synthesize carbon nanospheres with abovementioned properties, which involves interfacial assembly between layered double hydroxides nanosheets and polymer nanospheres, in-situ generation of nickel nanoparticles, and outside-in catalytic graphitization. The unusual phenomenon is that the in-situ generated nickel nanoparticles are preferentially oriented to the carbon side rather than to the free open space. The interface reactions between nickel nanoparticles and amorphous carbons drive continuous etching of carbon species to form graphitic structure in the interior of spheres. The graphitic structure can be tuned by changing effective charge ratio and pyrolysis conditions and obtained carbon nanospheres possessed good dispersibility in water and ethanol. Moreover, such carbon nanospheres exhibited good performance when used as anodes in lithium-ion batteries. These findings may pave new ways for synthesizing multifarious carbon nanomaterials with adjustable graphitic skeleton, developed porosity, good monodispersity and dispersibility for various applications.

Thermoregulated Phase-Transition Synthesis of Two-Dimensional Carbon Nanoplates Rich in sp2 Carbon and Unimodal Ultramicropores for Kinetic Gas Separation.

The development of highly selective, chemically stable and moisture-resistant adsorbents is a key milestone for gas separation. Porous carbons featured with random orientation and cross-linking of turbostratic nanodomains usually have a wide distribution of micropores. Here we have developed a thermoregulated phase-transition-assisted synthesis of carbon nanoplates with more than 80 % sp2 carbon, unimodal ultramicropore and a controllable thickness. The thin structure allows oriented growth of carbon crystallites, and stacking of crystallites in nearly parallel orientation are responsible for the single size of the micropores. When used for gas separation from CH4 , carbon nanoplates exhibit high uptakes (5.2, 5.3 and 5.1 mmol g-1 ) and selectivities (7, 71 and 386) for CO2 , C2 H6 and C3 H8 under ambient conditions. The dynamic adsorption capacities are close to equilibrium uptakes of single components, further demonstrating superiority of carbon nanoplates in terms of selectivity and sorption kinetics.