Space‐Confined Polymerization: Controlled Fabrication of Nitrogen‐Doped Polymer and Carbon Microspheres with Refined Hierarchical Architectures

Abstract

that are important indicators for use in photonics, biomedicine, catalysis, and advanced electrodes. [4] Current achievements related to porous carbon spheres mostly center on nanometer-sized spheres. [5] However, micrometer-sized spheres with refined hierarchical interior structures are highly desirable, because such structures not only enable spatiotemporal control of the chemical process occurring inside the spheres, but also reduce the difficulty of product separation compared with nanometersized spheres. [6] In particular, hierarchical porous carbon microspheres with large inner cavities, refined pore structure, and diverse functional groups are ideal hosts to anchor active guests through both physical and chemical interactions. [7] However, the fabrication of hierarchical porous carbon microspheres with such a refined structure is much more challenging than fabricating traditional carbon nanospheres, because it is extremely difficult to achieve the necessary delicate control of the interior structure and outer shell across the microscale to nanoscale.Although emulsion, spraying, dripping, and aerosol-assisted self-assembly methods have been explored to fabricate carbon microspheres, [6a,8] these microspheres do not possess complex interior structures because of the limitations of those methods in diversifying the assembly. [5] Solution synthetic methods have been widely applied for controllable fabrication of porous nanospheres. [9] It is nontrivial to extend solution synthetic methods to the fabrication of hierarchical porous carbon microspheres. Lu and co-workers reported a surface free energy-induced assembly approach to synthesize multicavity carbon nanospheres about 100 nm in diameter; this was the first direct synthesis of multicavity-structured carbon nanospheres by a controllable solution synthetic method. [7b] Yang and co-workers subsequently reported the synthesis of interiorstructured mesoporous carbon microspheres (50-200 µm in diameter) based on surfactant assembly within water droplet confined spaces. [5] To our knowledge, carbon microspheres of size ranging from sub-micrometer to a few micrometers with a refined hierarchical structure, based on a solution synthetic method, have not been reported. Moreover, the carbon precursors used by Lu and co-workers were both traditional phenolic resol; [5,7b] and the resultant carbons with homogeneousThe construction of refined architectures plays a crucial role in performance improvement and application expansion of advanced materials. The synthesis of carbon microspheres with a refined hierarchical structure is still a problem in synthetic methodology, because it is difficult to achieve the necessary delicate control of the interior structure and outer shell across the microscale to nanoscale. Nitrogen-doped multichamber carbon (MCC) microspheres with a refined hierarchical structure are realized here via a surfactant-directed spaceconfined polymerization strategy. The MCC precursor is not the traditional phenolic resol but a new kind of 2,6-di...

Recent advances in carbon-based supercapacitors

“…35 Furthermore, recently, Qiao's group designed a surfactant-assisted assembly approach to fabricate a series of multi-chamber carbon microspheres derived from 2,6-diaminopyridine. 36 A dual-surfactant system (F127 and sodium dodecylbenzenesulfonate) could induce the establishment of refined hierarchical architectures as well as tune the microsphere size in the scale of 250-3091 nm, and therefore, the as-synthesized electrode with a multi-chamber core and microporous shell functioned as a competitive supercapacitor material. As promising supercapacitor electrodes, porous carbon nanosheets possess high aspect ratios of 2D sheet-like morphologies for short ion-transfer channels; meanwhile, their porous architectures effectively prevent the layer overlapping/restacking of the rich interfacial accessible sites.…”

Mesoporous Nanoarchitectures for Electrochemical Energy Conversion and Storage

“…Wang et al designed hierarchically porous carbon spheres consisting of nanochambers in the central part as an electrode material for SCs (Figures 4m and 6e,f). [76] Due to high surface area and open pore structure, the hierarchically porous carbon spheres can store large amount of charges (Figure 6g). Moreover, the specific capacitance is almost unchanged after 5000 cycles at a high current density (5 A g −1 , Figure 6h), validating the excellent long-term cyclic stability.…”

Tailoring Polymer Colloids Derived Porous Carbon Spheres Based on Specific Chemical Reactions

“…(Figure 20). [111] The synthesis of MCP was accomplished in two major polymerization steps; step one involved mainly the methylolation of DAP, in which F127 was utilized as a steric stabilizer and SDBS formed vesicles with DAP-F, resulting in the formation of cytoskeleton-like DAP-F prepolymer microspheres in an alkaline solution. The second step began with the addition of an acid catalyst-acetic acid promoting further cross-linking of the DAP-F prepolymer.…”