Display omitted
•Prepared sponge like few layered reduced graphene nanosheets by thermal reduction method.•Boron doped graphene were successfully prepared by hydrothermal method for the first ...time.•Boron doped graphene atomic level (B-2.56at.%) and electrochemical applications.•Thermally reduced and Boron doped graphene for electrochemical supercapacitor applications.
Heteroatom doping in carbon nanostructured materials is one of the effective approaches to enhance the energy storage in supercapacitors. Graphene oxide (GO) was synthesized by thermal reduction under argon atmosphere at 500°C and boron doped graphene nanosheets were prepared through hydrothermal (HB-GNS) using boric acid (H3BO3). The atomic doping level of boron was calculated (2.56%) from X-ray photoelectron spectroscopic (XPS) studies. Electrochemical analysis of thermally reduced graphene nanosheets (T-GNS) and HB-GNS shows the electric double layer capacitance behavior in Cyclic Voltammetry (CV) study. The HB-GNS electrode exhibited a maximum specific capacitance of 113F/g (1A/g), where as T-GNS showed the specific capacitance of 53F/g (1A/g). The electrochemical impedance measurement shows low Rct values for HB-GNS as compared to the T-GNS materials. The boron doping (HB-GNS) increases twice the specific capacitance of T-GNS. These results indicate the superior electrochemical performance of HB-GNS due to boron doping in graphene nanosheets as high energy storage electrode materials for supercapacitors.
In the present work, facile preparation of MXenes based nanocomposite (MXene-CNTs) through catalytic chemical vapor deposition (cCVD) was demonstrated. The novel design of two and one-dimensional ...(2D/1D) MXene-CNTs composites for an extraordinary photocatalytic process for removal of Rhodamine B (RhB) using efficient photocatalytic dye degradations was compared to the performance of pure MXene. The surface morphological behavior of MAX, MXene and MXene-CNTs rational design of surface microstructure CNTs anchored on 2D materials MXene nanosheets product was characterized employing scanning electron microscopy (SEM). As-prepared direct growth CNTs by employing CVD method were in the size ranges of 40–90 nm as revealed from SEM images. The crystallographic structures of etching and delaminations of MAX and MXene-CNTs were observed for CNTs diffracted peaks at 2θ = 25.11° in support of (002) plan. The major C–O and (CC) stretching were confirmed. Prepared MXene and MXene-CNTs samples photocatalytic performance was investigated through photocatalytic Rhodamine B (RhB) dye degradation. MXene-based CNTs hybrid nanocomposites photocatalysts activity were estimated. The as-prepared pure MXene-RhB and MXene-CNTs-RhB materials calculated efficiency were 60 % and 75 %, respectively. The CVD preparations of new MXene-CNTs synthesis yield high and explored good successive cycles for hazardous pollutants.
Display omitted
•MXene-CNTs were prepared via novel catalytic chemical vapor deposition.•Pure MXene-RhB and MXene-CNTs-RhB efficiency were 60 % and 75 %.•Ti3C2-CNTs effective degraded (RhB) dyes at 3.5 times faster than pristine MXene.
In this study, a facile synthesis of chemical and thermal activation of biomass tea-waste materials was explored. A tea-waste biosource carbon was explored by chemical vapor deposition (CVD) method ...at 700 °C. The KOH-treated carbon (AC-KH) and H3PO4-treated carbon (AC-HP) were systematically studied for morphological characteristics and showed good morphological structures and a few transparent focused layered nanosheets. The elemental analysis done by scanning electron microscopy with energy-dispersive X-ray spectroscopy confirmed the presence of activated carbon. Fourier transform infrared spectroscopy (FT-IR) showed carbon-containing functional groups. The electrochemical analysis showed cyclic voltammetry (CV) curves for electric double layer capacitance (EDLC) with 3 M KOH electrolyte. The Nyquist plot obtained using electrochemical impedance spectroscopy (EIS) showed charge transfer resistance value (Rct) of 6.08 Ω. The electrochemical galvanostatic charge-discharge (GCD) study was conducted to obtain the specific capacitance (Scp) values of AC-KH, which were found to be 131.95 F/g at 0.5 A/g and also AC-HP active material was observed 55.76 F/g at 1 A/g. The AC-KH showed superior electrochemical performance when compared to AC-HP material. Hence, AC-KH is a promising active material for high-energy supercapacitor applications.
Display omitted
•Prepared AC-KH product exhibited good nanostructures.•AC-KH Product exhibited charge transfer resistance value Rct – 6.08 Ω.•AC-KH material exhibited 131.95 F/g specific capacitance (Scp) at 0.5 A/g.•AC-KH is a promising active material for high-energy supercapacitor.
To attain elevated class MXene (Ti3C2Tx) through a homemade kitchen blender method, high shear mechanical exfoliation is highly required for the efficient delimitations of MXene nanosheets from bulk ...MAX (Ti3AlC2). We examine large-scale industrial productions of the MXene nanosheets, where combing the predicted 2D materials using a blender is a first-time novel approach with the delaminating solvent as a dimethyl sulfoxide (DMSO). And also manually created layered MXene systems (handmade) delaminating MXene sheets (MX-H) was furthermore employed for environmental dye-degradations applications. The materials characterizations was done for both the bulk MAX, MX-H and the MX-B. Additionally, the surface morphological studies like scanning electron microscopy (SEM) were investigated for both MX-H and MX-B as-prepared samples. SEM images indicated the high shear blander technique formations highly expanded/delaminated MXene (Ti3C2Tx) nanosheets compared to MX-H samples. FTIR technique is employed to identify –OH, C–H, C–O stretching vibrations for both materials. Raman spectroscopy analysis of MX-H and MX-B revealed 484.80 cm−1 Raman shift assigned to E1g phonon mode of (Ti, C, O). The ultraviolet UV visible absorption spectra explored pure and catalyst added Methylene Blue (MB) dye stock solution using annular type photoreactor with visible light source of 300 W. The comparatives of MAX, MX-H and MX-B samples was investigated as photocatalytic activity, The blender made (MX-B) sample revealed 98% of efficiency.
Display omitted
•Elevated class MXene (Ti3C2) attained via homemade kitchen blender.•High shear mechanical exfoliation is required for efficient MXene delimitations.•Large-scale industrial productions of the MXene nanosheets.•2D materials using a blender is a first-time novel approach.•The blender made (MX-B) sample revealed 98% of efficiency.
This paper reported the successful preparation and characterization of bio-activated carbon nanosheets (ACNSs) synthesized from tamarind (tamarind indicia) fruits shells (TFSs) by employing Chemical ...Vapor Deposition (CVD) tubular furnace. The preparation of pure ACNSs and also potassium hydroxide (KOH) activated carbon nanosheets (K-ACNSs) were made through a pyrolysis process with Argon (Ar) gas as an inert gas at 800 °C for 2h 30min, followed by further purifications of K-ACNSs. The scanning electron microscope (SEM) images of ACNSs and K-ACNSs explored with and without pores respectively. The SEM micrographs also explored 3D-porous microstructure sheets with thickness around 18–65 nm. Raman spectroscopy explored crystallinity, SP2 order and graphitization at 1577–1589 cm−1. The major functional groups were also observed. The photoluminescence (PL) was analyzed for K-ACNSs materials and revealed carbon emission broad peak value at 521.3 nm. As prepared ACNSs and K-ACNSs active materials was applied for three-electrode materials of energy storage supercapacitor analysis of cyclic voltammeter for −0.4 – 0.15 V at scan rates of 10–100 mV/s. The electrochemical impedance spectroscopy (EIS) was performed with low Rct values of K-ACNSs as 0.65Ω when compared to pure ACNSs as 5.03Ω. Mainly, the galvanostatic charge-discharge test carried out in ACNSs and KCNSs materials was corresponded to 77 and 245.03 F/g respectively, with respect to 1 A/g current density. Finally, we promise that this reported novel tamarind bio-waste into conductive porous carbon nanosheets could develop future energy storage applications of biomass-derived carbons.
•New technique to prepare 3D pores activated carbon nanosheets were demonstrated.•Carbonization/pyrolysis of tamarind shells in argon (Ar) leads graphitic carbon.•ACNSs specific capacitance observed was 77 F/g at 1A/g.•KCNSs specific capacitance observed was 245.07 F/g at 1A/g.
Display omitted
•Electrochemical HER performance of MX@Pt was analyzed using 3 electrodes.•MX@Pt exhibited the 165 mV over potential to reach 10 mA/cm2 current density.•MX@Pt exhibited 477 mV ...overpotential to attain 100 mA/cm2.•MX@Pt solution resistance was found to be 1.61 Ω.•MX@Pt exhibited same current density even after 2 h stability test with 67% retention.
The 2D transition metal carbide, MXene (MX - TixCxTx) and MX@Pt nanocomposites was prepared from MAX (Ti3AlC2) precursor. The effective nanocomposite (MXene/Pt) photocatalysts are prepared by facile water bath sonication and CVD tubular furnace thermal annealing treatment at 600 °C. The successfully prepared MAX into MXene (MX) flakes are also compared to structural conformation of MX@Pt nanocomposites through XRD results and revealed good crystalline diffracted peaks. The micro-RAMAN results explored with excelent connection of 106.49 and 612.78 cm−1. The FT-IR substantiation for Ti-C and Ti-O-C stretching for MXene (TixCxTx) functional groups confirm the MAX, MX, MX@Pt materials formation. The surface FE-SEM morphology explored MXene few-layer sheets with ‘Pt’ decorated (MX@Pt) nanocomposites. Further, FE-SEM with EDAX elemental characterization system confirm materials atomic percentage as ‘Ti’– 48.36 at. %, ‘C”– 48.63 at. % and platinum ‘Pt’– 3.01 at. %. Finally, MX@Pt nanocomposites explored to HER studies, which exhibited 165 mV to attain 10 mA/cm2 and it exhibited 477 mV overpotential to reach 100 mA/cm2. MX@Pt nanocomposites revealed for H2 and HER activity applications will demonstrate future potential H2 productions and water splitting applications.
Carbon nanorods (CNRs) are significant one-dimensional carbon-based nanostructured materials. A new method to prepare direct growth fast-standing carbon nanorod as a promising electrode in symmetric ...supercapacitor applications has been explored. In this study, the CNRs are directly grown on SS plate in the three-zone horizontal chemical vapor deposition unit. The hydrogen free environment is used to grow the CNRs. The substrate position was studied by controlling the substrate temperature, time and precursor gas flow rate. Raman, Fourier transform infrared spectra (FTIR), high-resolution transmission electron microscopy (HR-TEM) explored CNRs formation. The CNRs are well assembled in the substrate and showed excellent electrical contact with it. The biological SP-150 instrument measured electrochemical activity of CNR-developed electrodes. The symmetric device was fabricated with two same electrodes and the device energy and power density was studied. Symmetric supercapacitor devices expressed 22 W h/kg energy density at low 1 A/g. The 96.65% capacity is maintained for 10,000 charge discharge cycles in symmetrical supercapacitor device.
Display omitted
•Prepared symmetric supercapacitor devices explored 22 Wh/kg at 1 A/g.•96.65% capacity is maintained for 10,000 cycles in symmetrical device.•Charge-discharge revealed 198 and 156 F/g in 3 and 2 electrode arrangements.
A new 2D transition metal carbides family noted that MXene with antimony (Sb) nano-needles composites have demonstrated potential applications for photocatalytic dye degradations applications. ...Single-step synthesis of novel structures two/one-dimensional MXene@antimony nanoneedle (MX@Sb–H) nanocomposite-based photocatalysts is produced employing hydrothermal technique. The preparations and characterizations were compared with hand mixture preparations of pure TiO2@Sb and MXene (MX@Sb-M). The crystallographic structure was identified employing X-ray diffraction (XRD) studies and main sharp XRD peaks were observed with diffraction angle with orientations planes for all three samples TiO2@Sb, MX@Sb-M and MX@Sb–H. The micro-Raman spectroscopy explored key vibration modes centered at 151.72 and 637.52 cm−1 corresponding to Ti and Sb hybrid composites respectively. Fourier transform infrared spectroscopy (FTIR) spectrum of functional group peaks at 609.16 and 868.80 cm−1 revealed Ti–OH/Sb–O–C stretching. The morphological investigations of horizontal growth for “Sb” nanoneedle on MXene nanosheets were explored by scanning electron microscopy (SEM). The degradation efficiency was calculated. The efficiency calculated were 27%, 38%, 68% and 82% for MB solution, TiO2@Sb added MB, MX-Sb-M added MB and MX-Sb-H added MB solution and the efficiency were 32%, 38%, 50% and 65% for pure RhB solution, TiO2@Sb added RhB, MX-Sb-M added RhB and MX-Sb-H added RhB solution. The photocatalytic activity of TiO2@Sb, MX@Sb-M and MX@Sb–H was examined. Among these MX@Sb–H nanocomposite was demonstrated the high photocatalytic action in expressions of rate stability of photocatalytic dye degradations.
•MXene (MX-(Ti3C2Tx)) with antimony (Sb) needle-like nanocomposites was developed.•MX@Sb–H showed a development in novel morphology.•First time TiO2@Sb, MX@Sb-M and MX@Sb–H focused for dye removal.
This work reports the direct growth of graphene nanofibers (GNFs) on metallic foils, namely nickel (Ni) and stainless steel (SS) and their use of direct device assembling of symmetric supercapacitor ...electrodes applications. GNFs were directly grown on Ni and SS through a chemical vapour deposition (CVD) technique, employing acetylene as a carbon source with 700 °C at 30 min. GNFs were grown on metallic foils with and without coating of NiNO3 catalytic layers by drop-casting method. As prepared GNFs on Ni and SS metallic foils were direct studied employing scanning electron microscope (SEM). The morphological images explored bending and curved nature forest growth of GNFs in cross-section micro-structure well growth of catalytic supports. The high-resolution morphological transmission electron microscope (TEM) results were explored highly branched multi-layers of graphene walls (d-spacing 0.34–0.48 nm) with GNFs size ranges of 100–50 nm. The micro-Raman spectrum results showed the IG/ID – 1.29 and also observed 2D-band at 2679.82 cm−1 for graphene layers for Ni-NiNO3-GNFs. The direct growth GNFs (Ni-NiNO3-GNFs) electrode was further investigated for the electrochemical supercapacitor device performance. The cyclic voltammetry (CV) results showed an ideal capacitive window (0.01–1.5 V) with impedance spectroscopy of 27.57 Ω Rct values. The direct assembled binder-free symmetric device is a new approach for supercapacitor applications with charge-discharge that Ni-NiNO3-GNFs sample has 24.66 F/g capacitance at 0.5 F/g. GNFs are in good contact with Ni and facilitate low Rct examined in impedance study. These overall results indicated well growth Ni-catalytic supports of bulk growth of graphene-like fibrous forest growth nanostructures on metallic foils. The prepared electrochemical energy storage symmetric device explored a good charge-discharge cycle as suitable for future high direct electrode applications for supercapacitor devices employing CVD techniques.
•GNFs explored multi-layers of graphene (d-spacing 0.34–0.48 nm) with 100–50 nm.•The micro-Raman spectrum results showed the IG/ID – 1.29.•Observed 2D-band at 2679.82 cm−1 for graphene layers for Ni-NiNO3-GNFs•The Ni-NiNO3-GNFs sample has 24.66 F/g capacitance at 0.5 F/g.
Facile synthesis of heteroatom doped graphene nanosheets is one of the recent trends in the development of energy storage materials like supercapacitors. Phosphorus doped graphene sheets (P-GNS) have ...been prepared using electrochemical method (EC), which is the most emerging technique for large scale synthesis. X-ray diffraction studies of as-electrochemically phosphorus doped graphene nanosheets (EC-P-GNS) synthesized show a shift towards lower 2θ values due to functionalized graphene sheets. Scanning electron microscopy analysis of EC-P-GNS shows folded and twisted type graphene nanosheets and the average sheet thickness was measured to be 40 nm. High resolution-transmission electron microscopy depth profile confirms the presence of few layer transparent graphene with twisted type sheets. Fourier transform-infra red analysis of EC-P-GNS confirms the presence of functional groups in the doped graphene sheets. X-ray photoelectron microscopy analysis of EC-P-GNS shows 0.68 % phosphorus atomic doping which confirms the P-doping in graphene nanosheets. The electrochemical performance was analyzed using EC-P-GNS and shows good cycle performance compared to graphite. The electrochemical charge/discharge curves of EC-P-GNS give a high specific capacitance (Csp) of 290 F g
−1
along with high energy density 43.75 Wh kg
−1
. Based on the above merits including higher Csp, we hope that our EC-P-GNS would be a promising material for super capacitors. Further, the prepared single pot electrochemical anodic erosion strategy provides easy scale up for all heteroatoms doped graphene nanosheets synthesis.
