Cobalt-doped porous carbon nanosheets derived from 2D hypercrosslinked polymer with CoN₄ for high performance electrochemical capacitors

Cobalt-doped graphene-coupled hypercrosslinked polymers (Co-GHCP) have been successfully prepared on a large scale, using an efficient RAFT (Reversible Addition-Fragmentation Chain Transfer Polymerization) emulsion polymerization and nucleophilic substitution reaction with Co (II) porphyrin. The Co-GHCP could be transformed into cobalt-doped porous carbon nanosheets (Co-GPC) through direct pyrolysis treatment. Such a Co-GPC possesses a typical 2D morphology with a high specific surface area of 257.8 m2 g−1. These intriguing properties of transition metal-doping, high conductivity, and porous structure endow the Co-GPC with great potential applications in energy storage and conversion. Utilized as an electrode material in a supercapacitor, the Co-GPC exhibited a high electrochemical capacitance of 455 F g−1 at a specific current of 0.5 A g−1. After 2000 charge/discharge cycles, at a current density of 1 A g−1, the specific capacitance increased by almost 6.45%, indicating the excellent capacitance and durability of Co-GPC. These results demonstrated that incorporation of metal porphyrin into the framework of a hypercrosslinked polymer is a facile strategy to prepare transition metal-doped porous carbon for energy storage applications

Patriotic Fun: Toys and Mobilization in China from the Republican to the Communist Era

This chapter explores the use of leisure to mobilize children in China from the 1910s to the early 1950s, in times of both war and peace. Drawing on normative advice, and commenting on youngsters’ reactions, it describes how ostensibly different regimes similarly deployed toys and play in order to foster children’s engagement in struggles of a political, commercial or military nature. It outlines how a variety of items - from so-called “educational” war toys to figurines and lanterns - could serve to rally children for the nation and familiarize war. The chapter argues that, although mobilization was construed as defensive, patriotic activism and acquaintance with the metaphorical or real battlefield were significant components of Chinese children’s upbringing from the beginning of the twentieth century

An interfacial engineering approach towards two-dimensional porous carbon hybrids for high performance energy storage and conversion

In order to improve the performance and fundamental understanding of conducting polymers, development of new nanotechnologies for engineering aggregated states and morphologies is one of the central focuses for conducting polymers. In this work, we demonstrated an interfacial engineering method for the rational synthesis of a two-dimensional (2D) polyaniline (PANI) nano-array and its corresponding nitrogen-doped porous carbon nanosheets. Not only was it easy to produce a sandwich-like 2D morphology, but also the thickness, anchored ions and produced various metal phosphides were easily and rationally engineered by controlling the composition of the aqueous layer. The novel structural features of these hybrids enabled outstanding electrochemical capacitor performance. The specific capacitance of the as-produced diiron phosphide embedded nitrogen-doped porous carbon nanosheets was calculated to be as high as 1098 F g−1 at 1 A g−1 and an extremely high specific capacitance of 611 F g−1 at 10 A g−1, outperforming state-of-the-art performance among porous carbon and metal-phosphide-based supercapacitors. We believe that this interfacial approach can be extended to the controllable synthesis of various 2D material coupled sandwich-like hybrid materials with potential applications in a wide range of areas

2D Porous Polymers with sp2‐Carbon Connections and Sole sp2‐Carbon Skeletons

International audience2D porous polymers with a planar architecture and high specific surface area have significant applications potential, such as for photocatalysis, electrochemical catalysis, gas storage and separation, and sensing. Such 2D porous polymers have generally been classified as 2D metal–organic frameworks, 2D covalent organic frameworks, graphitic carbon nitride, graphdiyne, and sandwich‐like porous polymer nanosheets. Among these, 2D porous polymers with sp2‐hybridized carbon (Csp2) bonding are an emerging field of interest. Compared with 2D porous polymers linked by B–O, C=N, or C≡C bonds, Csp2‐linked 2D porous polymers exhibit extended electron delocalization resulting in unique optical/electrical properties, as well as high chemical/photostability and tunable electrochemical performance. Furthermore, such 2D porous polymers are one of the best precursors for the fabrication of 2D porous carbon materials and carbon skeletons with atomically dispersed transition‐metal active sites. Herein, rational synthetic approaches for 2D porous polymers with Csp2 bonding are summarized. Their current practical photoelectric applications, including for gas separation, luminescent sensing and imaging, electrodes for batteries and supercapacitors, and photocatalysis are also discussed

Mass Transport Behaviors in Graphene and Polyaniline Heterostructure-Based Microsupercapacitors

The development of miniaturized energy storage components with high areal performance for emerging electronics depends on scalable fabrication techniques for thick electrodes and an in-depth understanding of the intrinsic properties of materials. Based on the coprecipitation behavior of electrically exfoliated graphene and reduced graphene oxide–templated polyaniline (PANi) nanoflake, this work develops a simple, green, low-cost, and scalable drop-casted technique to easily fabricate uniform thick electrodes (up to 80 μm) on various substrates. Through using a direct laser writing process, planar microsupercapacitors can be readily attained. As-fabricated flexible all-solid-state microsupercapacitors exhibit an ultrahigh areal capacitance of 172 mF cm−2 at 0.1 A cm−2 and excellent cycling stability of 91% capacitance retention over 2000 cycles at a high current density of 1.0 A cm−2. Furthermore, based on the electrochemical quartz crystal microbalance research result, the pseudocapacitance contribution is mostly provided by the adsorption/desorption of SO42− anions during the protonation process of PANi. This work offers a simple strategy toward superior-performance micro-sized energy devices and a new perspective to understand the origin of the capacitance of composites and heterostructures.QC 20230907</p

Potency of a Scalable Nanoparticulate Subunit Vaccine

Nanoparticulate vaccines can potentiate immune responses by site-specific drainage to lymph nodes (LNs). This approach may benefit from a nanoparticle engineering method with fine control over size and codelivery of antigen and adjuvant. Here, we applied the flash nanocomplexation (FNC) method to prepare nanovaccines via polyelectrolyte complexation of chitosan and heparin to coencapsulate the VP1 protein antigen from enterovirus 71, which causes hand–foot–mouth disease (HFMD), with tumor necrosis factor α (TNF) or CpG as adjuvants. FNC allows for reduction of the nanovaccine size to range from 90 to 130 nm with relatively narrower size distribution and a high payload capacity. These nanovaccines reached both proximal and distal LNs via subcutaneous injection and subsequently exhibited prolonged retention in the LNs. The codelivery induced strong immune activation toward a Th1 response in addition to a potent Th2 response, and conferred effective protection against lethal virus challenge comparable to that of an approved inactivated viral vaccine in mouse models of both passive and active immunization setting. In addition, these nanovaccines also elicited strong IgA titers, which may offer unique advantages for mucosal protection. This study addresses the issues of size control, antigen bioactivity retention, and biomanufacturing to demonstrate the translational potential of a subunit nanovaccine design