Mesoporous Graphene Research Articles

Organic polysulfanes grafted on porous graphene as an electrode for high-performance lithium organosulfur batteries

The performance of Li–S batteries is limited largely by the properties of the available sulfur electrodes. Here we report a novel composite sulfur electrode composed of organic polysulfane grafted directly on mesoporous graphene. Compared with sulfur chain based conventional organosulfur electrodes, the well-defined organic polysulfane with carbon skeleton has excellent structural stability during electrochemical cycling. Further, the mesopores on graphene sheets in this unique architecture can serve as channels to effectively facilitate rapid ion transport, leading to excellent battery performance. When tested as a free-standing electrode in a Li–S battery, the composite electrode demonstrates high capacity (1045 mAh/g at 1 C), superior rate capability (723 mAh/g at 20 C), excellent cycling stability (capacity retention of 95.3% after 1000 cycles at 5 C). The electrode materials still present good electrochemical performance even under high mass loading of sulfur (up to 20.3 mg/cm2). The remarkable electrochemical performance is attributed to the high structural stability and excellent electrical conductivity of the carbon skeleton and to the porous architecture of electrode that promotes fast ion transport. The greatly enhanced capacity and durability of the composite electrode make it ideally suited for the next-generation high-performance Li–S batteries.

Green synthesis of mesoporous graphene oxide/silica nanocomposites from rich husk ash: Characterization and adsorption performance

Abstract Rice husk is an agricultural waste. Rice husk ash (RHA) is the main residue when rice husk is burned to produce biomass energy. The conversion of RHA into high-value-added products is a sustainable method and can help develop a circular economy. In this study, a graphene oxide/SBA-15 composite was synthesized from RHA. Experimental investigations revealed that the various oxygen-containing functional groups of the graphene oxide/SBA-15 composite resulted in considerably enhanced adsorption capacity. Furthermore, the composite possessed a pore volume of 0.978 cm 3/g, pore size of 10.5 nm, and surface area of 625 m2/g. The pore structure of the composite was mainly a hexagonal array of mesopores, which did not change with the addition of GO. TEM images revealed that the SBA-15 surface was homogeneously covered with GO flakes. Raman spectroscopy demonstrated that composite contained disordered carbon with a high degree of oxidation. The effects of adsorption conditions – adsorbent dosage, initial dye concentration, adsorption temperature, and solution pH – on the Rhodamine B adsorption of the graphene oxide/SBA-15 composite were investigated. The composite exhibited the highest adsorption capacity of 151.28 mg/g at 80 ∘ C. The adsorption was endothermic with enthalpy of 11.83 kJ/mol. The isotherm adsorption experiment revealed that the Langmuir model was the best fit for the adsorption results. Kinetic investigations revealed that the adsorption process followed the pseudo-second-order model. The adsorption rate was mainly controlled by the intraparticle diffusion step. Commercially available SBA-15 materials are expensive. This study provides an economically viable method of treating RHA that improves its potential for applications involving removal of dyes from wastewater.

In-situ functionalization of binder-free three-dimensional boron-doped mesoporous graphene electrocatalyst as a high-performance electrode material for all-vanadium redox flow batteries

The development of highly efficient and stable nanostructured electrocatalysts, capable of operating at a high current density is crucial to the broader market penetration of vanadium redox flow batteries (VRFBs). In this report, three-dimensional (3D) boron-doped mesoporous graphene functionalized carbon felt (BMG-CF) is fabricated and tested as the positive and negative electrodes for VRFB. Morphological results show that BMG-CF exhibits a homogenous distribution of boron atoms and the electrochemical testing indicates outstanding electrocatalytic activity towards VO2+/VO2+ and V2+/V3+ redox couples compared to activated-CF (A-CF) and mesoporous graphene-CF (MG-CF), ascribed to introduction of B-doped mesoporous structures and high electrical conductivity. Notably, BMG-CF attain energy efficiencies (EE) of 81.5% and 74.4% at 100 mA cm−2 and 150 mA cm−2, which are 9.4% (3.0%) and 17.3% (4.3%) higher than A-CF (MG-CF) electrodes. Furthermore, the battery can be operated at very high current densities of 175 mA cm−2 and 225 mA cm−2 with EE of 70.7% and 60.0% and exhibit excellent cycle stability for more than 100 cycles at 100 mA cm−2 with superior rate capability at current densities of 50–225 mA cm−2. The above excellent results demonstrate the practical applicability of the highly efficient and stable 3D BMG-CFs as promising electrodes for VRFB.

Electrochemical sensor for rutin detection based on N-doped mesoporous carbon nanospheres and graphene

A new electrochemical sensor shows great sensing performance to rutin and high selectivity towards even 13 interfering species and realizes detection of rutin in real samples such as human serum.

Mesoporous silica-coated graphene nanosheets for uniform lithium deposition toward stable lithium metal anode

Herein, we demonstrate an ideal mesoporous silica-coated graphene nanosheets constructed host for lithium metal anode. In this hybrid anode, the mesoporous silica layers on every graphene nanosheet possess abundant mesopores (3.3 nm), high specific surface area and pore volume. More importantly, the insulating mesoporous silica layers enable the lithium metal to uniformly plate on the graphene inside the nanosheets, thus effectively inhibit the growth of lithium dendrites and volume change. As a consequence, this as-prepared hybrid anode exhibits a relatively low overpotential of less than 12 mV at 1 mA cm−2 and a stable value of 13 mV after 150 cycles.

Cur-loaded ZnFe2O4@mZnO@N-GQDs biocompatible nano-carriers for smart and controlled targeted drug delivery with pH-triggered and ultrasound irradiation

In the present study a pH/ultrasound (US)-responsive nano-carriers based on magnetic core-shell ZnFe2O4@mZnO@GQDs and ZnFe2O4@mZnO@N-GQDs ternary composite was prepared. The smart nano-carrier contain a magnetic zinc ferrite (ZnFe2O4) core, mesoporous zinc oxide (mZnO) and graphene quantum dots doped with nitrogen (N-GQDs) interlayer shell that prepared by sol-gel and/or the hydrothermal methods. This nano-carrier was used for pH/ultrasound-controllable curcumin (Cur) reagent release. The structural, thermal and morphological properties of each nano-carrier was investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray (EDX), surface area measurements, transmission electron microscopy (TEM), selected area electron diffraction pattern (SAEDP) image, field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), thermo gravimetric analyzer (TGA), dynamic light scattering (DLS), zeta potential, and Brunauer−Emmett−Teller (BET). Also, the cytotoxicity assay of nano-carriers have been studied on the fibroblast and Hela cells. No in vitro cytotoxic effects have observed at high concentration (75 μg/mL) of nanocarriers. The Cur drug loading efficiency of nano-carriers were as high as 76.45% w/w (ZnFe2O4@mZnO-N-GQDs) and 64.71% w/w (ZnFe2O4@mZnO-GQDs). The loaded Cur can be sustainably released, and could be controlled by US irradiation and pH adjustment. Thus, these core-interlayer-shells are suitable for smart and controlled targeted drug release by using pH and US irradiation.

Graphene encapsulated NiS/Ni3S4 mesoporous nanostructure: A superlative high energy supercapacitor device with excellent cycling performance

Innovative materials with excellent cyclic performance become the mantra for energy storage. Graphene encapsulated NiS/Ni3S4 (NSG) nanostructure is synthesized via polyethylene glycol assisted one-step hydrothermal method. The encapsulated nanostructure is examined for supercapacitor applications. The NSG nanostructure offers a large specific capacity of 827 C g−1 at 5 A g−1 (pristine PEG assisted nickel sulphide yields 574 C g−1) and shows good cyclic stability (88%) and Coulombic efficiency (95%) after 5000 cycles at a high and practically useful specific current of 70 A g−1. The superior electrochemical performance of NSG is due to its high conductivity, high surface area, a synergistic effect between the graphene and nickel sulphide and their mesoporous graphene encapsulated nanostructure. The NSG and reduced graphene oxide based asymmetric supercapacitor device achieves a maximum energy density of 86.3 W h kg−1 at 2 A g−1 with excellent device stability (98%) over 5000 cycles. The superior electrochemical features of NSG makes it a potential electroactive material for supercapacitor applications.

Aminosilicate modified mesoporous anatase TiO2@graphene oxide nanocomposite for dye-sensitized solar cells

Highly ordered aminosilicate modified mesoporous anatase TiO2 graphene oxide (mTiO2@GO/NH2) nanocomposite microspheres are prepared by hydrothermal method and are investigated using various spectral and microscopic techniques. X-ray photoelectron spectroscopy and Fourier-transform infrared spectral analyses confirmed the presence of NH2 groups in the mTiO2@GO/NH2 nanocomposites. The mTiO2@GO/NH2 exhibits lower photoluminescence intensity than bare mesoporous TiO2 microspheres, disclosing an efficient photoelectron transfer from the mesoporous TiO2 to GO through aminosilicate chain. Atomic force microscopic analysis reveals that mTiO2@GO/NH2 thin film has highly ordered porous structure. The highly porous mTiO2@GO/NH2 exhibits good dye loading for light harvesting and allow good electrolyte contact, which minimizes the back-electron transfer between photoanode and oxidized dye molecules. The dye-sensitized solar cell (DSSC) based on mTiO2@GO/NH2 nanocomposite photoanode, with optimum amount of (3-aminopropyl)triethoxysilane (APTES), delivers an overall photo-conversion efficiency of 5.11%, which is 2.5-fold higher than that of the DSSC based on pure mesoporous TiO2 microspheres (mTiO2 MS) photoanode. The significant photovoltaic performance of the present DSSC based on mTiO2@GO/NH2 photoanode is due to synergistic effects between the TiO2 and GO heterojunction.

3D hierarchically macro-/mesoporous graphene frameworks enriched with pyridinic-nitrogen-cobalt active sites as efficient reversible oxygen electrocatalysts for rechargeable zinc-air batteries

Efficient and affordable electrocatalysts for reversible oxygen reduction and oxygen evolution reactions (ORR and OER, respectively) are highly sought-after for use in rechargeable metal-air batteries. However, the construction of high-performance electrocatalysts that possess both largely accessible active sites and superior ORR/OER intrinsic activities is challenging. Herein, we report the design and successful preparation of a 3D hierarchically porous graphene framework with interconnected interlayer macropores and in-plane mesopores, enriched with pyridinic-nitrogen-cobalt (pyri-N-Co) active sites, namely, CoFe/3D-NLG. The pyri-N-Co bonding significantly accelerates sluggish oxygen electrocatalysis kinetics, in turn substantially improving the intrinsic ORR/OER activities per active site, while copious interlayer macropores and in-plane mesopores enable ultra-efficient mass transfer throughout the graphene architecture, thus ensuring sufficient exposure of accessible pyri-N-Co active sites to the reagents. Such a robust catalyst structure endows CoFe/3D-NLG with a remarkably enhanced reversible oxygen electrocatalysis performance, with the ORR half-wave potential identical to that of the benchmark Pt/C catalyst, and OER activity far surpassing that of the noble-metal-based RuO2 catalyst. Moreover, when employed as an air electrode for a rechargeable Zn-air battery, CoFe/3D-NLG manifests an exceedingly high open-circuit voltage (1.56 V), high peak power density (213 mW cm−2), ultra-low charge/discharge voltage (0.63 V), and excellent charge/discharge cycling stability, outperforming state-of-the-art noble-metal electrocatalysts.

Assessment of three-dimensional nitrogen-doped mesoporous graphene functionalized carbon felt electrodes for high-performance all vanadium redox flow batteries

We demonstrate the synthesis of three-dimensional (3D) nitrogen doped mesoporous graphene-functionalized carbon felt (NMG-CF) via a facile hydrothermal process. These NMG-CF act as electrocatalysts in an all-vanadium redox flow battery (VRFB). NMG-CF exhibits a uniform distribution of nitrogen atoms and spectroscopic studies indicate successful N-doping in the form of pyridinic-N, pyrrolic-N, quaternary-N and oxidic-N configurations. NMG-CFs show superior electrocatalytic activity towards V2+/V3+ and VO2+/VO2+ redox couples than activated-CF (A-CF) and mesoporous graphene-CF (MG-CF). Furthermore, NMG-CF exhibits 14–16% greater energy and voltage efficiencies than A-CF at 150 mA cm−2, with an excellent rate capability and cycling stability at current densities of 50–275 mA cm−2. These enhancements are attributed to improved hydrophilicity, 3D N-doped mesoporous structures, enhanced specific surface area and rapid charge/electron transfer. Moreover, N-doping generates defects acting as active sites and alters the electronic and chemisorption properties of NMG due to the large electronegativity difference between C and N atoms, making NMG-CFs more electrochemically accessible than A-CF and MG-CF. Notably, electrocatalytic activity is dependent not only on N-doping content but also on nitrogen configuration. The above results reveal the great potential of NMG-CFs as advanced electrode materials for VRFB.

Boosting the cyclic stability and supercapacitive performance of graphene hydrogels via excessive nitrogen doping: Experimental and DFT insights

Nitrogen-doped mesoporous graphene hydrogel (MGHG) enjoys many unique characteristics for use as an efficient energy storage electrode material. Herein, a green one-pot hydrothermal synthesis strategy was employed to synthesize highly hydrophilic nitrogen-doped mesoporous graphene hydrogel. The morphological, structural, and compositional analyses were performed using FESEM, XRD, and XPS techniques. The as-prepared MGHG exhibits high wettability (contact angle = 58.9o), high surface area (318.226 m2/g), and an unprecedented nitrogen doping content of 2.95%. The fabricated MGHG was evaluated as a supercapacitor material in 1 M aqueous K2SO4 electrolyte, revealing a maximum specific capacitance of 595.7 F.g−1 with a low equivalent series resistance (0.1664 Ω) that is ascribed to the high porosity, high surface area, and the available nitrogen redox active sites. To further elucidate the electrochemical performance of MGHG, a symmetric supercapacitor device was assembled using MGHM as negative and positive electrodes. The fabricated device shows a maximum specific energy of 30 Wh kg−1 corresponding to a specific power 1000 W kg−1. The density functional theory (DFT) computations were utilized to better understand the high performance of the assembled devices. These superior results demonstrate the excellent performance of MGHG as a potential material for highly-performing supercapacitor devices with a potential window of 2.2 V.

Microwave-prepared mesoporous graphene as adsorbent and matrix of surface-assisted laser desorption/ionization mass spectrometry for the enrichment and rapid detection of polyphenols in biological samples

In this work, a three-dimensional mesoporous graphene (3D-MG) prepared by microwave-assisted method was used as both the adsorbent and the matrix of SALDI-TOF MS for polyphenols analysis in biological samples. The outstanding microstructure of 3D-MG made it sensitive in small molecule analysis with low background interference and able to enrich trace polyphenols from complex samples. 3D-MG performed much better in the detection of small molecules than graphene prepared by ordinary method, and could further improve sensitivity and reduce detection limit by enrichment. Due to its unique hierarchical mesoporous structure, the interference of biological macromolecules in SALDI analysis could be eliminated after treatment by 3D-MG. Finally, 3D-MG was successfully applied to the screening of polyphenols in biological samples with simple process and high throughput. Moreover, this strategy had also promoted the development of new matrix in SALDI-TOF MS analysis, in which the matrix properties, adsorption capabilities and size effects of graphene-based materials were combined for the first time.

Mesoporous Iron Oxide Nanoparticle-Decorated Graphene Oxide Catalysts for Fischer–Tropsch Synthesis

Hierarchically mesoporous iron oxide/graphene oxide (GO) composites have been synthesized by a facile, one-step hydrothermal method and utilized as Fischer–Tropsch synthesis (FTS) catalysts. The ca...

Designing Champion Nanostructures of Tungsten Dichalcogenides for Electrocatalytic Hydrogen Evolution.

Fine-tuning strain and vacancies in 2H-phase transition-metal dichalcogenides, although extremely challenging, is crucial for activating the inert basal plane for boosting the hydrogen evolution reaction (HER). Here, atomically curved 2H-WS2 nanosheets with precisely tunable strain and sulfur vacancies (S-vacancies) along with rich edge sites are synthesized via a one-step approach by harnessing geometric constraints. The approach is based on the confined epitaxy growth of WS2 in ordered mesoporous graphene derived from nanocrystal superlattices. The spherical curvature imposed by the graphitic mesopores enables the generation of uniform strain and S-vacancies in the as-grown WS2 nanosheets, and simultaneous manipulation of these two key parameters can be realized by simply adjusting the pore size. In addition, the formation of unique mesoporous WS2 @graphene van der Waals heterostructures ensures the ready access of active sites. Fine-tuning the WS2 layer number, strain, and S-vacancies enables arguably the best-performing HER 2H-WS2 electrocatalysts ever reported. Density functional theory calculations indicate that compared with strain, S-vacancies play a more critical role in enhancing the HER activity.

Nitrogen-doped mesoporous graphene nanoflakes for high performance ionic liquid supercapacitors

Mesoporous nitrogen-doped graphene nanoflakes (N-GNFs) with high nitrogen doping level of 5.0–10.7 at.% were produced by a facile template CVD synthesis using the mixture of acetonitrile and benzene as a precursor. The pore structure, morphology and physicochemical properties of N-GNFs were characterized by TEM, XPS, Raman spectroscopy, and low-temperature nitrogen physisorption. The electrochemical performance of N-GNFs was tested in electric double-layer capacitor (EDLC) with ionic liquid electrolyte (1.2 M N+Et4TFSI− solution in CH3CN) by cyclic voltammetry, galvanostatic charge-discharge measurements, and electrochemical impedance spectroscopy. With increasing the nitrogen content in N-GNFs their specific capacitance increased and achieved 167 F g−1 at a scan rate of 5 mV s−1. The maximum delivered energy density was 46.3 Wh kg−1, which corresponded to a power density of 0.74 kW kg−1. The high electrochemical performance of N-GNFs was attributed both to the pseudo-capacitance of active nitrogen sites and to the developed mesoporosity. Different tetraalkylammonium bis(trifluoromethylsulfonyl)imide ionic liquids were used to evaluate the cation size effect on the stability and performance of N-GNFs-based EDLCs. In contrast to N+Et4TFSI− and N+Bu4TFSI− electrolytes, the cycling performance of N-GNFs in N+Me4TFSI− was limited because of the electrode degradation resulted from the intercalation of N+Me4 ions between graphene layers and their exfoliation.

Structural evolution of mesoporous graphene/LiNi1/3Co1/3Mn1/3O2 composite cathode for Li–ion battery

Layered LiMO2 (M = Ni, Co, and Mn) is a type of promising cathode materials for high energy density and high work voltage lithium-ion batteries. However, the poor rate performance and low power density hinder its further applications. The capacity fade is related to the structural transformation in the layered LiMO2. In this work, the structural changes of bi-material cathode composed of mesoporous graphene and layered LiNi1/3Co1/3Mn1/3O2 (NCM) were studied via in situ X-ray diffraction (XRD). During different C-rate charge–discharge test at the voltage range of 2.5–4.1 V, the composite cathode of NCM−graphene (NCM−G) reveals better rate performances than pure NCM cathode. The NCM−G composite electrode displays a higher rate capability of 76.7 mAh·g−1 at 5C rate, compared to the pure NCM cathode of 69.8 mAh·g−1 discharge capacity. The in situ XRD results indicate that a reversible phase transition from hexagonal H1 to hexagonal H2 occurs in layered NCM material during 1C charge–discharge process. With the current increasing to 2C/5C, the structure of layered NCM material for both electrodes reveals few changes during charge and discharge processes, which indicates the less utilization of NCM component at high C-rates. Hence, the improved rate performance for bi-material electrode is attributed to the highly conductive mesoporous graphene and the synergistic effect of mesoporous graphene and NCM material.

Synergetic effect of nitrogen and sulfur co-doping in mesoporous graphene for enhanced energy storage properties in supercapacitors and lithium-ion batteries

Nitrogen and sulfur co-doped mesoporous graphene (NSMG) was fabricated via a hydrothermal method followed by heat treatment utilizing graphite oxide (GO), tri-block co-polymer P123 and thiourea as the N and S source. The porous structure of the NSMG was controlled by heat treatment at 600 ​°C and 800 ​°C thus obtaining NSMG600 and NSMG800 which had specific surface areas of 966 and 1335 ​m2 ​g−1, respectively. X-ray photoelectron spectroscopy (XPS) of the NSMGs demonstrated the presence of active pyridinic-N, pyrrolic-N, graphitic-N, pyridinic N- oxide, thiophene and –SOx groups in the structure. The N and S contents and configurations were controlled by annealing temperature hence influencing the performance in supercapacitors (SC) and lithium-ion batteries (LIBs). There was improved electrolyte ion mobility and lithium-ion diffusion for both SCs and LIBs respectively. The improved performance could be attributed to the unique structural features such as plentiful defects, wrinkles, abundant pores, and N/S co-doping. NSMG600 exhibited the highest capacitance of 261 ​F ​g−1 at 0.5 ​A ​g−1 in SCs while NSMG800 showed the best performance in LIBs with a discharge capacity of 460 mAh g−1 at 100 ​mA ​g−1 with good cycling stability (440 mAh g−1) and superior rate capability. Thus NSMGs exhibit potential application in high-performance energy storage devices.

Nitrogen doping of mesoporous graphene nanoflakes as a way to enhance their electrochemical performance in ionic liquid-based supercapacitors

Abstract Ionic liquid (IL) electrolytes can enhance specific energy of electrical double layer supercapacitors (EDLCs) due to their large operating voltage. In this work mesoporous nitrogen-doped graphene nanoflakes (NGs) with the high doping level of 9.0 at.% produced by the facile template synthesis were tested as EDLC electrodes in ionic liquid electrolytes. High mesoporosity of NGs provided the rapid transfer of IL ions into electrode pores and the effective charge accumulation, while nitrogen doping improved the wettability of the NG surface with electrolytes and contributed to pseudo-capacitance. The high electrochemical performance of NG-based EDLCs was confirmed by cyclic voltammetry, galvanostatic charge-discharge measurements and impedance spectroscopy. The effect of cation size on the specific capacitance was also analyzed for two pairs of IL electrolytes (N+Et4TFSI− and N+Bu4TFSI−; EMIM+TFSI− and BMIM+TFSI−). The highest specific capacitance of 136 F g−1 was achieved for the optimal combination of NG mesoporous structure and IL cation size.

Atomically Dispersed Iron-Nitrogen Sites on Hierarchically Mesoporous Carbon Nanotube and Graphene Nanoribbon Networks for CO2 Reduction.

Atomically dispersed metal and nitrogen co-doped carbon (M-N/C) catalysts hold great promise for electrochemical CO2 conversion. However, there is a lack of cost-effective synthesis approaches to meet the goal of economic mass production of single-atom M-N/C with desirable carbon support architecture for efficient CO2 reduction. Herein, we report facile transformation of commercial carbon nanotube (CNT) into isolated Fe-N4 sites anchored on carbon nanotube and graphene nanoribbon (GNR) networks (Fe-N/CNT@GNR). The oxidization-induced partial unzipping of CNT results in the generation of GNR nanolayers attached to the remaining fibrous CNT frameworks, which reticulates a hierarchically mesoporous complex and thus enables a high electrochemical active surface area and smooth mass transport. The Fe residues originating from CNT growth seeds serve as Fe sources to form isolated Fe-N4 moieties located at the CNT and GNR basal plane and edges with high intrinsic capability of activating CO2 and suppressing hydrogen evolution. The Fe-N/CNT@GNR delivers a stable CO Faradaic efficiency of 96% with a partial current density of 22.6 mA cm-2 at a low overpotential of 650 mV, making it one of the most active M-N/C catalysts reported. This work presents an effective strategy to fabricate advanced atomistic catalysts and highlights the key roles of support architecture in single-atom electrocatalysis.

The effect of cationic CTAB surfactants on the performance of graphene electrode for supercapacitor

Graphene is a two-dimensional sp2 bonded carbon nanostructure packed in a honeycomb crystal lattice. Graphene has a high theoretical surface area and electrical conductivity that is suitable for the electrode of supercapacitors. There are many methods to produce graphene, such as mechanical exfoliation using scotch tape, reduction of graphene oxide, and chemical vapor deposition. An alternative and simple method to produce graphene is through pyrolysis process. The previous study shows that the production of graphene from biomass via two-stage pyrolysis process results in an increase of the surface area; however, its capacitance is still low to be applied as the electrode for supercapacitor. This study aims to modification of graphene surface using cetyltrimethylammonium bromide (CTAB) as the surfactant. The graphene was produced from palm kernel shell via two-stage pyrolysis method (the first stage was at 350°C followed by the second stage at 900°C) using FeCl3 as catalyst and ZnCl2 as activating agent, resulting in 16% yield. Graphene was analyzed using Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Raman scattering, X-ray Diffraction (XRD), and Fourier Transform Infrared (FTIR). These analyses show that the two-stage pyrolysis produces multi-layered graphene. The surface properties were analyzed by nitrogen adsorption-desorption measurements, which show some mesoporous graphene product with a surface area of 351.27 m2/g. The result exhibited more hydrophilic graphene than the unmodified one, but according to the Cyclic Voltammetry (CV) analysis, the specific capacitance of modified graphene (11.91 Fg-1) is lower than unmodified graphene (43.87 Fg-1).