Construction of hierarchically porous biomass carbon using iodine as pore-making agent for energy storage

High specific surface area, hierarchical porosity, high conductivity and heteroatoms doping have been considered as the dominating factors of high-performance carbon-based supercapacitors. Inspired by the blue phenomenon of combination of starch and iodine, iodine is employed firstly as pore-making agent to create micropores for the starch-derived carbon in this study. Based on this mechanism, the hierarchically porous carbon is synthesized through simple solvent heating and high-temperature (1000 °C) carbonization, which achieves high specific surface area of 2989 m² g^-1 (an increase of 39.7% compared to that without iodine) and low electrical resistivity of 0.21 Ω·cm. The assembled symmetric supercapacitors, combined with dual redox-active electrolyte (Bi³⁺ and Br^-), deliver the specific capacitance of 1216 F g^-1, energy density of 65.4 Wh kg^-1, as well as power density of 787.3 W kg^-1 at 2 A g^-1. In brief, the abundant biomass resource starch is exploited as carbon source, and the iodine sublimation reaction is conducted to provide more micropores to develop high-performance electrodes of supercapacitors.

Facile synthesis of highly porous "carbon sponge" with adsorption and co-adsorption behavior of lead ions and atrazine

The rapid industrialization and modern agriculture, increasing emission of heavy metals, and abusing application of pesticide have changed biochemical features of the soil system and water system. Additionally, heavy metals and pesticide compounds may occur together in environments, giving rise to more serious damage to the environment because of their combined toxicity and carcinogenic properties. Therefore, there is a growing need for the development of low-cost adsorbents for their removal. Porous carbon materials have been considered as highly effective materials for pollutant ion control. In this thesis, a novel porous "carbon sponge" is produced using sucrose (S-PCS) with gas-producing molten salt KHCO₃ as the activator at different pyrolysis temperatures under a limited-oxygen condition. Results from these characterizations have indicated that the as-prepared carbon sponges share high surface area (up to 457.6434 m² g^-1) and abundant oxygen-containing functional groups existed on the surface. The essential factors of contact time, initial concentrations, and cyclic availability on adsorption of lead ions and atrazine onto the as-prepared porous samples are also discussed. The typical kinetic and thermodynamic models are carried out to interpret the adsorption behaviors of lead ions and atrazine. The interactive effects and mechanism of lead ions and atrazine adsorption onto S-PCS samples are examined by simultaneous adsorption and preloading adsorption procedures. Combined with the economic and environmental merits of the raw materials, the porous carbon sponges of sucrose by KHCO₃ activated are promising materials for potential practical applications. Graphical abstract The schematic diagram on the preparation of porous carbon sponse from sucrose.

Recent Trends on Electrochemical Sensors Based on Ordered Mesoporous Carbon

The past decade has seen an increasing number of extensive studies devoted to the exploitation of ordered mesoporous carbon (OMC) materials in electrochemistry, notably in the fields of energy and sensing. The present review summarizes the recent achievements made in field of electroanalysis using electrodes modified with such nanomaterials. On the basis of comprehensive tables, the interest in OMC for designing electrochemical sensors is illustrated through the various applications developed to date. They include voltammetric detection after preconcentration, electrocatalysis (intrinsically due to OMC or based on suitable catalysts deposited onto OMC), electrochemical biosensors, as well as electrochemiluminescence and potentiometric sensors.