Localized eddy current heating-driven synthesis and regeneration of porous carbons at mitigated energy cost

Abstract

Porous carbons (PCs), widely deployed sorbents in diverse areas, are usually synthesized by thermochemically carbonizing carbonaceous precursors and thermally regenerated at great energy-cost. To seek alternative solutions to such energy penalty and based on the exceptional localized Eddy current heating (LECH) capacity of metal objects upon their exposure to an alternating magnetic field, LECH-driven synthesis of PCs is explored and exemplified by using nickel foam (NF)-delivered LECH to drive carbonization of phenolic resin (PR) infilled within the voids of NF, producing varied PC-incorporated NFs (NF@PCs). Compared with the PCs prepared by using conventional tubular furnace heating, LECH-driven carbonization of PR is able to produce PCs at lower temperature and with greatly enhanced porosity, surface area and graphitization degree, which are mainly resulting from the localized heating nature of LECH. Driven by the same NF-delivered LECH, the moisture adsorbed in the LiCl-loaded NF@PC can be rapidly and completely released at moderate temperature, demonstrating the highly efficient LECH-driven regeneration of PCs. Given that the LECH is delivered by cost-effective and widely available NFs, occurs within the matrix of PR and PC bulk solid, and remotely triggered by an external magnetic field with greatly mitigated energy loss, LECH-driven carbonization of PR and water desorption from PCs thus demonstrated a new, energy-efficient and low-cost strategy to effectively synthesize and regenerate PCs.