Synthetic Bio-Graphene Based Nanomaterials through Different Iron Catalysts

Abstract

Kraft lignin was catalytically graphitized to graphene-based nanostructures at 1000 °C under argon atmosphere with four iron catalysts, iron(III) nitrate (Fe-N); iron(II) chloride (Fe-Cl2); iron(III) chloride (Fe-Cl3); and iron(II) sulfate (Fe-S). The catalytic decomposition process of iron-promoted lignin materials was examined using thermalgravimetric analysis and temperature-programmed decomposition methods. The crystal structure, morphology and surface area of produced materials were characterized by means of X-ray diffraction, Raman, scanning electron microscopy, high resolution transmission electron microscopy and N2 adsorption−desorption techniques. Experimental results indicated that iron nitrate catalyst had better iron dispersion three other iron salts. Iron nitrate was the most active catalyst among four iron salts. The low activity of iron in iron chloride-promoted samples was because the residual chlorine over iron surfaces prevent iron interaction with lignin functional groups.

Lignin‐derived electrochemical energy materials and systems

“…The synthesis of graphene from renewable and abundant biomass feedstocks using simple pyrolysis reactions has therefore been proposed and is regarded as a promising route, especially considering the unique polymeric structure of lignin, which is comprised of aromatic rings and condensed linkages and shows great similarity to the hexagonal structure of graphene, which makes it an excellent precursor for producing graphene and graphene‐like materials . Some valuable studies on graphene and graphene‐like carbon materials derived from biomass lignin have been reported . As shown in Fig.…”

“…There are three typical synthesis routes from lignin to graphene, including: (i) Catalytic graphitization with transitional metals/metal salt catalysts; (ii) direct carbonization in an inert atmosphere; and (iii) a two‐step route involving oxidative cleavage and aromatic refusion . Among these, catalytic graphitization is the most widely used synthesis route for lignin‐derived graphene materials.…”

Effect of Solvents on Fe–Lignin Precursors for Production Graphene-Based Nanostructures

“…According to the MCW concept, graphene-encapsulated core–shell nanoparticles are first prepared by catalytic graphitization of solid carbon resources [ 1 , 3 ]. To obtain good catalytic effect, a uniform catalyst-solid carbon mixture must be made [ 2 , 4 ]. A major issue in catalytic graphitization of solid carbon resources including biomass is the contact degree between catalysts and raw carbon materials [ 5 ].…”

“…The degree of catalyst–solid carbon contact is generally poor if a metallic catalyst powder is just simply mixed with lignin [ 6 ]. Practically, metal salts, instead of metal particle powder, are used to obtain high metal dispersion in solid carbon and improve its catalytic performance [ 2 , 4 ]. Catalyst–solid biomass material precursors are usually prepared with an impregnation method: a dry biomass material is added to a metal salt solution which will be absorbed by the biomass material because of the capillary forces produced by its inner pores.…”

“…Specifically, kraft lignin has relatively high hydrophobicity since it is condensed to huge molecules when recovered from black liquors through the acidity precipitation process; the polymer chains are entangled and curled, and a metal salt aqueous solution is repelled due to its hydrophobic property. Therefore, it is very difficult for metal ions to penetrate kraft lignin particles if an impregnation method is used, which yields a poor contact degree between metal and kraft lignin [ 2 , 4 ]. Fortunately, there are significant oxygen-containing functional groups of lignin, i.e., aliphatic hydroxyl in the propane sidechains, phenolic hydroxyl, methoxyl, and carbonyl groups [ 8 ].…”