Nitrogen-Doped Porous Carbons Derived from Triarylisocyanurate-Cored Polymers with High CO₂ Adsorption Properties

A series of N-doped porous carbon materials have been successfully prepared by using nitrogen-rich triarylisocyanurate-cored polymers as carbon precursor. The cross-linked networks explain the precursor with high carbonaceous residues in the following carbonization. The influence of KOH dosage and activation temperature on the specific surface area and nitrogen content of the resultant carbon materials is investigated in detail. Eventually, a maximum specific surface area of 2341 m² g^–1 and nitrogen content of 1.7 wt % are achieved in the resultant carbon materials. High CO₂ capacity (30.2 wt % at 273 K/1 bar and 17.2 wt % at 298 K/1 bar) is attributed to abundant microporous structures and basic sites, superior to that of the most porous carbon materials reported in the previous literature. In addition, the carbon materials also demonstrate high H₂ and CH₄ uptake (2.7 wt % at 77.3 K/1.13 bar and 3.8 wt % at 273 K/1.13 bar, respectively). The characters of easy preparation and high gas uptake capacity endow this kind of carbon material with promising applications for CH₄, H₂, and CO₂ uptake

Facile Preparation of Core–Shell Fe₃O₄@Polypyrrole Composites with Superior Electromagnetic Wave Absorption Properties

Core–shell Fe₃O₄@polypyrrole (PPy) composites with excellent electromagnetic wave absorption properties have been prepared by a sequential process of etching, polymerization, and replication. Templating from pre-prepared Fe₃O₄ microspheres, ferric ions were released from the skin layer of the microspheres by acid etching and initiated the oxidative polymerization of pyrrole in suit. The morphological and textural evolution of core–shell Fe₃O₄@PPy composites depending on etching time was investigated by scanning and transmission electron microscope. A maximum reflection loss of as much as −41.9 dB (>99.99% absorption) at 13.3 GHz with a matching layer thickness of 2.0 mm was achieved when the etching time was 5 min. In comparison with other conductive polymer-based core–shell composites reported previously, the Fe₃O₄@PPy composites in this study not only possess better reflection loss performance but also demonstrate a wider effective absorption bandwidth (<−10.0 dB) over the entire Ku band (12.0–18.0 GHz). The excellent electromagnetic wave absorption properties of the core–shell Fe₃O₄@PPy composites are mainly attributed to the enhanced dielectric loss from the PPy shell

Hierarchically Porous Carbons Derived from Biomasses with Excellent Microwave Absorption Performance

A variety of biomass-based carbon materials with two-level porous structure have been successfully prepared by one-step carbonization process. The first level of microscale pores templates from the inherent porous tissues, while the second one of nanopores is produced by the in situ etching by the embedded alkaline metal elements. The superimposed effect of nano and microscale pores endows the hierarchically porous carbons (HPCs) with excellent microwave absorption (MA) performance. Among them, the spinach-derived HPC exhibits a maximum reflection loss of −62.2 dB and a broad effective absorption bandwidth of 7.3 GHz. Particularly, this excellent MA performance can be reproduced using the biomass materials belonging to different families, harvested seasons, and origins, indicating a green and sustainable process. These encouraging findings shed the insights on the preparation of biomass-derived microwave absorbents with promising practical applications

Hierarchically Porous Carbon Derived from PolyHIPE for Supercapacitor and Deionization Applications

Hierarchically porous carbon (HPC) materials with interconnected porous texture are produced from a porous poly­(divinylbenzene) precursor, which is synthesized by polymerizing high-internal-phase emulsions. After carbonation, the macroporous structures of the poly­(divinylbenzene) precursor are preserved and enormous micro-/mesopores via carbonation with KOH are produced, resulting in an interconnected hierarchically porous network. The prepared HPC has a maximum specific surface area of 2189 m² g^–1. The electrode materials for supercapacitors and capacitive deionization devices employing the formed HPC exhibit a high specific capacity of 88 mA h g^–1 through a voltage range of 1 V (319 F g^–1 at 1 A g^–1) and a superior electrosorption capacity of 21.3 mg g^–1 in 500 mg L^–1 NaCl solution. The excellent capacitive performance could be ascribed to the combination of high specific surface area and favorable hierarchically porous structure