Insights into forming behavior and CO₂ adsorption properties of graphene from Sargassum horneri by Fe(NO₃)₃/KOH activation

Abstract

BACKGROUND Macroalgae biomass as a graphene source shows great potential at large scale in an energy shortage era. To achieve a more moderate and economic graphene synthesis method, porous graphenes were synthesized using Sargassum horneri as precursor, in combination with Fe(NO3)3 and KOH composite. RESULTS The addition of 10 wt% Fe(NO3)3 obviously accelerated KOH activation and decreased KOH loading and reaction temperature. Meanwhile, the graphene synthesized by Fe(NO3)3/KOH had better regeneration performance than that activated merely by KOH, even under more moderate thermal condition. The porous graphene displayed high specific surface area (~2311 m2 g−1) and exhibited good CO2 uptake capacity (~4.39 mmol g−1) at 30 °C and 1 bar. The CO2 adsorption rate equations of the graphene were consistent with the intraparticle diffusion model, indicating that CO2 adsorption was mainly controlled by the pore structure and additionally influenced by the chemical functional groups. CONCLUSION The present work focuses on the high value‐added comprehensive utilization of macroalgae, which not only has important significance for on‐scale preparation of bio‐originated graphene and CO2 adsorption, but also has positive benefits for macroalgae resource development. © 2022 Society of Chemical Industry (SCI).

Biomass-Derived Carbonaceous Materials with Graphene/Graphene-Like Structures: Definition, Classification, and Environmental Applications

“…Second, suitable preparation routes must be designed to ensure the optimal applicability of the derived BGS. The generation of more graphene/graphene-like structures can be attributed to the decomposition, polymerization, and aromatization of biomass, the combination of amorphous carbon with the metal catalysts, and the carbide formation–decomposition mechanism at high temperatures. , Considering that the graphitization process is complex, the introduction of artificial intelligence and machine learning is expected to provide a new development direction for the preparation and application of BGS. − …”

“…72−74 References to graphite and graphene-like structures as "graphene" and "few-layer graphene" in previous studies may have been incorrect. Few-layer graphene has been prepared via KOH activation using Sargassum horneri as a precursor; 44 however, high I 2D /I G ratios (1.78−1.94) and poorly defined 2D peaks in the Raman spectra indicated that the obtained BGS comprised porous graphene-like structures. Dead camphor leaves have been used to develop few-layer graphene; 75 however, the D, G, and 2D bands in the Raman spectra were poorly defined with the average I D /I G ratio of 0.99, possibly as a result of multilayer structural defects and residual chemical groups, thus suggesting the formation of graphene-like material rather than few-layer graphene.…”

“…The generation of more graphene/graphene-like structures can be attributed to the decomposition, polymerization, and aromatization of biomass, the combination of amorphous carbon with the metal catalysts, and the carbide formation− decomposition mechanism at high temperatures. 5,44 Considering that the graphitization process is complex, the introduction of artificial intelligence and machine learning is expected to provide a new development direction for the preparation and application of BGS. 110−112 Third, conversion efficiency and economic efficiency are the main limiting factors for industrial production and commercial operation of BGS.…”

“… − Graphene and graphene-like carbon nanosheets have been synthesized from various types of biomass via several promising methods, such as pyrolysis activation, chemical vapor deposition, chemical exfoliation, modified Hummers’ method, and microwave/plasma (Table S1, Figure S1). − State-of-the-art methods currently used to determine the structural properties of BGS include Raman spectra, atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer–Emmett–Teller (BET) surface area analysis. ,, The ISO/TS 21356-1:2021 standard suggests that an initial examination using Raman spectra is necessary to determine whether a sample contains graphene or graphitic material (Figure a). Then, a sequence of SEM, TEM, AFM, and BET measurements should be collected to allow detailed description and characterization of the material, and comparisons should be made against the “Graphene and Related 2D Materials” (ISO/TS 80004-13) standard and the ISO/TS 21356-1 standard.…”

Turn Waste Golden Tide into Treasure: Bio-Adsorbent Synthesis for CO2 Capture with K2FeO4 as Catalytic Oxidative Activator

“…Inspired by our previous work, the addition of Fe did significantly accelerate the activation of K and reduced the KOH loading and reaction temperature. The carbon materials synthesized from Fe(NO 3 ) 3 /KOH as co-activator had higher specific surface area and better CO 2 uptake capacity than those activated only by KOH [ 29 , 30 ]. Therefore, K 2 FeO 4 will be an effective activator for CO 2 bio-adsorbent preparation.…”