A Study of the Key Factors on Production of Graphene Materials from Fe-Lignin Nanocomposites through a Molecular Cracking and Welding (MCW) Method

Abstract

In this work, few-layer graphene materials were produced from Fe-lignin nanocomposites through a molecular cracking and welding (MCW) method. MCW process is a low-cost, scalable technique to fabricate few-layer graphene materials. It involves preparing metal (M)-lignin nanocomposites from kraft lignin and a transition metal catalyst, pretreating the M-lignin composites, and forming of the graphene-encapsulated metal structures by catalytic graphitization the M-lignin composites. Then, these graphene-encapsulated metal structures are opened by the molecule cracking reagents. The graphene shells are peeled off the metal core and simultaneously welded and reconstructed to graphene materials under a selected welding reagent. The critical parameters, including heating temperature, heating time, and particle sizes of the Fe-lignin composites, have been explored to understand the graphene formation mechanism and to obtain the optimized process parameters to improve the yield and selectivity of graphene materials.

Upgrading Lignin into Graphene‐Based Materials: State of the Art and Perspectives

“…There are several reaction parameters, including reaction temperature, MCW temperature, particle size, and reaction time, influencing the MCW effectiveness. [ 52 ] In the case of using CH 4 as a cracking/welding gas, the optimal conditions included a welding temperature of >1000 °C, heating time of 0.5–1 h, and particle size of 150–250 nm for Fe‐lignin nanocomposites.…”

Production of COx-Free Hydrogen and Few-Layer Graphene Nanoplatelets by Catalytic Decomposition of Methane over Ni-Lignin-Derived Nanoparticles

“…The catalytic stability may be attributed to the nickel dispersion in the Ni@G sample. The cracked graphene shells may also participate in the CDM reaction as the vacancy defects and edges in the cracked graphene shells can serve as the active sites for methane decomposition [25][26][27]. The vacancies and edge carbon atoms with free bonds in the cracked graphene shells tend to react with methane molecules by catching the carbon atoms to stabilize their structures.…”

Tuning thermal and graphitization behaviors of lignin via complexation with transition metal ions for the synthesis of multilayer graphene-based materials

“…Moreover, the MCW operation enables additional tailoring of graphene properties while facilitating the separation of multilayer graphene shells from metal particles. 20 This novel process is scalable and proved to be highly effective for transforming kra lignin into multilayer graphene-based materials.…”

“…16 The MCW operation was found to play an important role in the graphene manufacturing process as different operation conditions of this step can result in graphene materials with different forms, such as nanoplatelets, sheets, and uffy agglomerates. 18,20 For example, the temperature has a profound effect on the degree of graphitization, while atmosphere (gas medium) for MCW can inuence graphitic structures, morphologies, and yields. However, how the structure and properties of M@G materials are altered by different metal catalysts during the MCW process remains unclear.…”