Supercapacitive performance of hydrous ruthenium oxide (RuO<Subscript>2</Subscript>·<Emphasis Type="Italic">n</Emphasis>H<Subscript>2</Subscript>O) thin films deposited by SILAR method

The amorphous hydrous ruthenium oxide (RuO₂·nH₂O) thin films were deposited by a simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method. These films were characterized for their structural, surface morphological, and compositional study by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDAX) techniques. The wettability test was carried out by measuring the water contact angle. The scanning electron microscopy study showed small RuO₂ particles are grouped together to form porous agglomerates. The FT-IR study confirmed the formation of hydrous ruthenium oxide films. The hydrophilic nature of ruthenium oxide (RuO₂·nH₂O) thin films was observed from water contact angle measurement. The presence of Ru and O in the film was confirmed by EDAX analysis. The supercapacitor behavior of these films studied in 0.5 M H₂SO₄ electrolyte showed maximum specific capacitance of 162 F g⁻¹ at 10 mV s⁻¹ scan rate. These films exhibit 80% cycling performance after 2,000 cycles. The charge–discharge studies carried at 1 mA cm⁻² current density revealed the specific power of 3.5 KW kg⁻¹ and specific energy of 29.7 W Kg⁻¹ with 93% coulombic efficiency.     

A new asymmetric supercapacitor based on λ-MnO2 and activated carbon electrodes

Lithium-ion intercalated compound λ-MnO₂ was used as positive electrode in asymmetric supercapacitor with activated carbon used as negative electrode in 1 mol L^− 1 Li₂SO₄ aqueous electrolyte solution. Phase composition, morphology and particle sizes of λ-MnO₂ were studied by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). Electrochemical capacitive performance of the asymmetric supercapacitor was tested by cyclic voltammetry and galvanostatic charge-discharge tests. The results show that the asymmetric supercapacitor has electrochemical capacitance performance within wide potential range of 0-2.2 V. The specific capacitance is 53 F g^− 1 at a constant current density of 10 mA cm^− 2. The energy density is 36 W h kg^− 1 with a power density of 314 W kg^− 1. It is obvious that λ-MnO₂ is a potential electrode material for asymmetric supercapacitor.     

Enhanced formation of ruthenium oxide nanoparticles through green synthesis for highly efficient supercapacitor applications

Ruthenium oxide nanoparticles (RuO₂ NPs) are one of the most promising materials at nanoscale, for energy storage devices. In the present work, a bottom up approach was utilized to synthesize RuO₂ NPs using biological resources, as reducing agent. Root extract of traditionally important medicinal plant, Akarkara (Anacyclus pyrethrum), was used in this study as the reducing agent. The investigation was carried out without the addition of any external reaction catalyzing agent. The Characterization studies were performed to analyze the conformational nature of the nanoparticles through XRD, SEM, TEM with SAED and FTIR spectroscopy was done to assess the functional moieties. Cyclic voltammetric (CV) studies were carried out to investigate the electrochemical potential of the synthesized RuO₂ NPs using the extract. The results demonstrated that the biologically reduced nanoparticles were crystalline, spherical and with an average size of 13 nm. The RuO₂ NPs were observed to be highly stable even after repeated usage. CV analysis revealed that capacitance behavior was reversible in nature and the specific capacitance of RuO₂ NPs using Akarkara (Anacyclus pyrethrum) coated over carbon sheet was 209 Fg⁻¹ at a scan rate of 5 mV/s. These results proved that green biosynthesis of RuO₂ can be used for supercapacitor applications.     

Sonochemical synthesis,characterization, and electrochemical properties of MnMoO4 nanorods for supercapacitor applications

In this article, we reported the preparation of manganese molybdate (MnMoO₄) nanorods by a facile sonochemical method and investigated its electrochemical properties for supercapacitor applications. The microstructure, surface morphology and composition were characterized by using field emission scanning electron microscope (FE-SEM), high resolution-transmission electron microscopy (HR-TEM), X-ray diffraction analysis (XRD), Raman spectroscopy and X-ray photo electron microscopy (XPS). The cyclic voltammetry (CV) curves of sonochemically synthesized α-MnMoO₄ nanorods revealed the presence of redox pairs suggesting the pseudocapacitive nature of MnMoO₄. A maximum specific capacitance of the α-MnMoO₄ nanorods was about 168.32 F g⁻¹ as observed from the galvanostatic charge–discharge (GCD) analysis at a constant current density of 0.5 mA cm⁻². Long term cyclic stability study revealed that about 96% of initial capacitance was retained after 2000 cycles.     

Samarium-decorated ZrO2@SnO2 nanostructures,their electrical,optical and enhanced photoluminescence properties

In the present work, pure ZrO₂@SnO₂ and Samarium (Sm_x) (x?=?1%, 8% and 12%)-doped ZrO₂@SnO₂ nanoparticles (NPs) successfully synthesized by facile low-cost co-precipitation technique. As-synthesized nanostructures (NS) were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), UV–visible, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), Brunauer–Emmett–Teller (BET) spectroscopic investigation. The tetragonal crystal phase of the as-synthesized Sm_x:ZrO₂@SnO₂ NS confirmed by XRD analysis. The observed peak shift in the XRD patterns confirmed incorporation of dopant into host lattice. The Sm_x:ZrO₂@SnO₂ NS present irregular spherical morphology and high agglomeration confirmed by FESEM microscope analysis. The presence of functional groups, chemical bonding, chemical constituents and valence state of the NS confirmed by FT-IR and XPS analysis. The Sm_x:ZrO₂@SnO₂ NS showed higher surface area and smaller optical band gap (454 cm²/g and 2.12 eV) than the pure ZrO₂@SnO₂ NS (189–196 cm²/g and 2.84 eV). Photoluminescence (PL) spectra of undoped ZrO₂@SnO₂ and Sm_x:ZrO₂@SnO₂ NS exhibited oxygen vacancies. Undoped ZrO₂@SnO₂ NS exhibited emission intensity at 370.6 nm (λ_excitation?=?300 nm) whereas, Sm_x:ZrO₂@SnO₂ NS showed emission intensities at 453.4 nm, 476.3 nm, 601.3 nm (λ_excitation?=?300 nm). Electrical property studies of Sm_x:ZrO₂:SnO₂ (1%, 8% and 12%) NS showed large variation in Hall constant (0.125?×?10⁶ cm²/coulomb to 0.647?×?10⁶ cm²/coulomb) with proportionately large variation in the resistivity (147.8 Ω-cm to 456.8 Ω-cm) for all the doped samples as compared with pure ZrO₂@SnO₂ NS. The Sm³⁺-doped ZrO₂@SnO₂ NS showed higher stability, intense PL emission and enhanced electrical properties.

     

Structural,optical, electrical properties,and relative humidity sensor application of PVA/Dextrin polymeric blend loaded with silicon dioxide nanoparticles

In the current study, polymer composite films (PCFs) of polyvinyl alcohol (PVA) and Dextrin (60/40) wt% without and with 0.03 and 0.06 wt% silicon dioxide nanoparticles (SiO₂NPs) were synthesized via casting way. The structural properties of the matrix polymer blend (MPB) were investigated using X-ray diffraction and revealed an amorphous structure. However, some kind of crystallinity has appeared after embedding the SiO₂NPs. The chemical functional groups were analyzed via FTIR spectra. The surface morphology characteristics were performed utilizing an optical microscope (OPM), and the images showed that SiO₂NPs were well diffused in MPB without any agglomerations. The optical properties were studied in the wavelength range between 190 and 1100 nm. Up to 97% of UV rays were blocked by PCFs at λ?=?270 nm and the absorption edges decreased from 4.05 to 3.80 eV. The values of the allowed and forbidden energy gap (E_g) decreased from 4.18 to 3.75 eV and from 3.98 to 3.73 eV, respectively, with the existence of the NPs. In addition, the electrical conductivity (σ_ac) values were increased with the increase in frequency f and NPs content. The use of SiO2NPs has shown highly improved dielectric and energy dissipation characteristics and has a high sensitivity to relative humidity in various NPs ratios, temperatures, time and RH ranges.

     

Influence of synthetic parameters on the enhanced photocatalytic properties of ZnO nanoparticles for the degradation of organic dyes: a green approach

Herein, we report a green synthetic strategy using aqueous leaves extract of Actinodaphne madraspatna Bedd (AMB) for the synthesis of ZnO NPs. The physical shape, size, thermal stability, surface area, surface composition and chemical state, morphological and optical properties of the synthesized ZnO NPs are well characterized through UV–Visible diffuse reflectance spectroscopy (DRS UV), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, thermal gravimetric analysis–differential thermal analysis (TGA–DTA), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) and X-ray photon spectroscopy (XPS). FT-IR spectrum of ZnO NPs showed a characteristic peak at 416.62 cm^?1. Optical studies of prepared ZnO NPs showed the bandgap values are reduced in the range of 3.05 to 2.96 eV. The XRD and TEM data revealed the synthesized ZnO NPs exist in wurtzite crystal structure with crystallite sizes of 18 nm to 68 nm range. The variation in bandgap, surface area and crystallite structure of ZnO NPs would be achieved by changing the experimental parameters. FESEM showed spherical-shaped structure. XPS result confirmed the atomic states of Zn and O. The green synthesized ZnO NPs were examined for the photocatalytic degradation of methylene blue (MB) and acid violet 17 (AV17) dyes under UV light and the rate constants ‘k’ was calculated. It is found that the green synthesized ZnO NPs with reduced bandgap showed enhanced photocatalytic activity with higher rate constant.

     

Green synthesis of lanthanum oxide nanoparticles using Moringa oleifera leaves extract and its biological activities

Phytosynthesis is a reliable way to produce metal nanoparticles without affecting the environment. Plant extracts act as reducing agent and favors nanoparticle synthesis. Recently, potential drugs were developed in nanotechnology platforms by the green synthesis approach. In this study, the leaves extract of ‘Moringa Oleifera’ (M. oleifera) used as a reducing agent for the synthesis of Lanthanum oxide nanoparticles (La₂O₃ NPs). The X-ray diffraction (XRD) confirmed the formation of body-centered cubic structure of La₂O₃ NPs. The optical behavior of La₂O₃ NPs was analyzed by UV–Vis spectrum. The bandgap energy of the La₂O₃ NPs was found to be 4.31 eV using Tauc’s plot. The morphology and purity of La₂O₃ NPs was analyzed by using Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-ray (EDX) spectrum. High Resolution Transmission Electron Microscope (HR-TEM) analysis reveals the morphology, lattice spacing, and selected area electron diffraction (SAED) pattern of the La₂O₃ NPs. The XPS analysis of the La₂O₃ NPs reveals the binding energy of La (3d_5/2 and 3d_3/2) and O 1s at 835.5, 852.3, and 536 eV respectively. The total antioxidant activity (TOA) of La₂O₃ NPs was found to be 75.32% at 500 µg/mL with the standard drug of vitamin C. The anti-inflammatory activity of the La₂O₃NPs was found to be 94.15% at 500 µg/mL using the bovine serum albumin denaturation (BSA) technique. The inhibitory activity of La₂O₃ NPs against α-amylase was found to be 79.99% at 500 µg/mL. In summary, the pure, highly stable and good biocompatible, greener approach based M. oleifera assisted La₂O₃ was synthesized for radical scavenging, α-amylase and BSA denaturation inhibition activities which can play a key role in the future biomedical and nano-biotechnological applications.     

Comparative photocatalytic performance and therapeutic applications of zinc oxide (ZnO) and neodymium-doped zinc oxide (Nd–ZnO) nanocatalysts against Acid Yellow-3 dye: kinetic and thermodynamic study of the reaction and effect of various parameters

Zinc oxide (ZnO) nanoparticles (NPs) were synthesized hydrothermally and doped with 4% Neodymium (Nd). The produced NPs were characterized using UV–Vis spectroscopy, X-ray diffraction (XRD), Energy dispersive X-ray analysis, Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA) and Photoluminescence (PL) spectroscopy. With the addition of 4% Nd, the bandgap reduced from 3.20 to 3.00 eV which confirmed successful doping with Nd which also evident from FTIR study. The XRD study showed hexagonal structure of the synthesized material, while SEM study confirmed that Nd-doped ZnO (Nd–ZnO) NPs are well dispersed as compare to ZnO. TGA study revealed that synthesized NPs were much stable to temperature and only 11.3% and 7.2% the total loss occurred during heating range (40–600 °C) in case of ZnO and Nd–ZnO NPs, respectively. The PL intensity of the visible peaks of ZnO reduced after doping with Nd. The degradation of Acid yellow-3 over both the catalysts followed first-order kinetics. The activation energy calculated for the photodegradation reaction was 43.8 and 33.7 kJ/mol using pure ZnO and Nd–ZnO NPs, respectively. About 91% and 80% dye was degraded at the time interval of 160 min using Nd–ZnO and ZnO NPs, respectively. High percent degradation of dye was found at low concentration (10 ppm) and at optimal dosage (0.035 g) of the catalyst. The rate of Acid yellow-3 dye degradation was found to increase with increase in temperature (up to 50 °C) and pH(8) of the medium. The recyclability study showed that both pure ZnO and Nd–ZnO NPs could be reused for the degradation of the given dye. With the addition of H₂O₂ up to 5 µL, the rate of reaction increased clearly indicating the effect of OH^· generation during photocatalysis. When compared with Nd–ZnO NPs at low concentrations, ZnO NPs at higher concentrations were found to be less hazardous. Both the NPs showed best antibacterial activities against Staphylococcus aureus. The hemolytic study indicated that at low concentration, pure ZnO was non-hemolytic as compared to Nd–ZnO.

     

Novel synthesis of hafnium oxide nanoparticles by precipitation method and its characterization

Hafnium oxide nanoparticles (HfO₂ NPs) have been successfully synthesized by means of a novel precipitation method and were characterized by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Field emission scanning electron microscopy (FESEM), UV–visible, Fourier transform infrared (FTIR) and laser Raman spectroscopy. The XRD and Raman analysis revealed the presence of pure monoclinic HfO₂ NPs. FESEM image showed that the HfO₂ NPs were of spherical shape with an average particle size of about 20 nm. The optical band gap of the HfO₂ NPs was found to be 6.12 eV. Advantages of this method were simple and low cost of synthesis of HfO₂ NPs includes the small and narrow particle size distribution.     

Intercalation of IR absorber into layered double hydroxides: Preparation,thermal stability and selective IR absorption

N-phosphonomethyl aminodiacetic acid (PMIDA) was intercalated into the interlayer spacing of layered double hydroxides (LDH) by an anion-exchange method. The intercalated LDHs were characterized by various techniques such as powder X-ray diffraction (XRD), FT-IR spectroscopy, elemental analysis and simultaneous thermogravimetric and mass spectrometry (TG-MS) in details. The results show the formation of Mg₂Al-PMIDA LDH based on the expansion of d-spacing from 0.89 nm to 1.22 nm and the disappearance of the characteristic IR absorption band at 1384 cm^?1 for NO₃^? anions. The incorporation of Mg₂Al-PMIDA LDH into the low density polyethylene (LDPE) as an additive enhances the selectivity of IR absorption in the main wavelength region 9–11 μm for radiant heat loss at night. Mg₂Al-PMIDA LDH as a heat-retaining additive has practical application in agricultural plastic films.     

Development of redox deposition of birnessite-type MnO2 on activated carbon as high-performance electrode for hybrid supercapacitors

Birnessite-type MnO₂/activated carbon nanocomposites have been synthesized by directly reducing KMnO₄ with activated carbon in an aqueous solution. It is found that the morphologies of MnO₂ grown on activated carbon can be tailored by varying the reaction ratio of activated carbon and KMnO₄. An asymmetric supercapacitor with high energy density was fabricated by using MnO₂/activated carbon (MnO₂/AC) nanocomposite as positive electrode and activated carbon as negative electrode in 1 M Na₂SO₄ aqueous electrolyte. The asymmetric supercapacitor can be cycled reversibly in the cell voltage of 0–2 V, and delivers a specific capacitance of 50.6 F g⁻¹ and a maximum energy density of 28.1 Wh kg⁻¹ (based on the total mass of active electrode materials of 9.4 mg), which is much higher than that of MnO₂/AC symmetric supercapacitor (9.7 Wh kg⁻¹).     

First-principles study of CaCu3B4O12 (B=Co, Rh, Ir)

Employing first-principles density functional theory based calculations we investigated the change in electronic structure of CaCu₃B₄O₁₂ compounds as one moves from 3d (Co) to 4d (Rh) to 5d (Ir) element at B site. Our study sheds light on valences of Cu and B ions as one moves from 3d to 4d to 5d based compounds. The valence of Cu in Co and Rh compound turn out to be that of less known 3+ state, while that in Ir compound turn out to be commonly known 2+ state. Our first-principles study provide microscopic understanding of these different valences of Cu, in terms of changes in the mixing of Cu x ² − y ² and B-a _1g states, driven by changes in the crystal field and spin splitting. The stronger crystal field splitting for 4d and 5d elements compared to 3d at B site drive the low-spin state at Rh and Ir site as opposed to intermediate spin in case of Co.     

Densification of (Na,K)NbO<Subscript>3</Subscript> piezoelectric ceramics by two-step mixing process

Lead-free Na_0.5K_0.5NbO₃ (NKN) piezoelectric ceramics were sintered with a new process, “two-step mixing process,” in which a part of alkali source powders was initially preserved and mixed with the rest matrix powders after the calcinations step. As a result, the sintering of NKN ceramics was improved, and the sample sintered at 1082 °C with the initial preservation ratio (R _A) of 5% demonstrated the highest density of ρ = 4.38 g/cm³ (97.1% of the theoretical density), compared with ρ = 4.36 g/cm³ (96.7% of the theoretical density) for the non-preservation specimen (R _A = 0%). The former sample showed the best piezoelectric constant of d ₃₃ = 125 pC/N and electromechanical coupling coefficient of k _p = 0.42, while the latter sample had d ₃₃ = 116 pC/N and k _p = 0.37. These results indicated that the two-step mixing process was effective for the sintering of lead-free NKN ceramics, despite no sintering additive and cold isostatic pressing were used.     

Structural investigation of xFe2O3 · (100 − x)[P2O5 · TeO2] glass system by FT-IR study and EPR spectroscopy

Glasses from xFe₂O₃ · (100 − x)[P₂O₅ · TeO₂] system, with 0 ≤ x ≤ 50 mol%, were investigated by X-ray diffraction, FT-IR and EPR spectroscopies. The XRD patterns show a vitreous state of studied samples for x ≤ 35 mol% Fe₂O₃. The FT-IR spectrum of the P₂O₅ · TeO₂ glass matrix reveals a structure formed from PO₄, TeO₄ and TeO₃ units. The addition and the increasing of Fe₂O₃ content modify progressively the structure of the glass matrix. The local structure in the investigated glasses was revealed by means of EPR using Fe³⁺ (3d⁵; ⁶S_5/2) ions as paramagnetic probes. The EPR spectra present two resonance absorption lines characteristic to Fe³⁺ ions centred at g_eff ≈ 2.0, for 0.5 ≤ x ≤ 35 mol% and g_eff ≈ 4.3, for 0.5 ≤ x ≤ 5 mol%. The variation of the EPR parameters, the intensity and line-width of these absorption lines, with iron ions composition has been followed.     

Synthesis,structural and electrical properties of triethylene glycol (TREG) stabilized Mn0.2Co0.8Fe2O4 NPs

Triethylene glycol (TREG) stabilized Mn_0.2Co_0.8Fe₂O₄ NPs was synthesized by a glycothermal reaction. XRD analysis identified the product as Mn_0.2Co_0.8Fe₂O₄ with a high phase purity. Nano-sized particles with an average size of about 6–8 nm were obtained with nearly single crystalline nature with TEM analysis. Superparamagnetic-like behavior of TREG stabilized Mn_0.2Co_0.8Fe₂O₄ NPs was observed by VSM. The binding between TREG and Mn_0.2Co_0.8Fe₂O₄ NPs was investigated with FT-IR and found to be via O on the TREG and NP surface. TG analysis indicated that the Mn_0.2Co_0.8Fe₂O₄ NP content was about 40%, with a TREG-shell content to be around 60%. Overall conductivity of the nanocomposite is in the range of 10^?10 to 10^?7 S cm^?1 with a strong dependence on temperature and frequency, indicating ionic conductivity. The nanocomposite exhibited lower ?’ and ?″ compared to TREG stabilized Mn_0.2Co_0.8Fe₂O₄ NPs due to the doping of co-doping of manganese and cobalt.     

Synthesis and characterization of Piperidine-4-carboxylic acid functionalized Fe3O4 nanoparticles as a magnetic catalyst for Knoevenagel reaction

Piperidine-4-carboxylic acid (PPCA) functionalized Fe₃O₄ nanoparticles as a novel organic–inorganic hybrid heterogeneous catalyst was fabricated and characterized by XRD, FT-IR, TGA, TEM and VSM techniques. Composition was determined as Fe₃O₄, while particles were observed to have spherical morphology. Size estimations using X-ray line profile fitting (10 nm), TEM (11 nm) and magnetization fitting (9 nm) agree well, revealing nearly single crystalline character of Fe₃O₄ nanoparticles. Magnetization measurements reveal that PPCA functionalized Fe₃O₄ NPs have superparamagnetic features, namely immeasurable coercivity and absence of saturation. Small coercivity is established at low temperatures. The catalytic activity of Fe₃O₄–PPCA was probed through one-pot synthesis of nitro alkenes through Knoevenagel reaction in CH₂Cl₂ at room temperature. The heterogeneous catalyst showed very high conversion rates (97%) and could be recovered easily and reused many times without significant loss of its catalytic activity.     

Synthesis and characterization of a clay/waterborne polyurethane nanocomposite

A novel clay/waterborne polyurethane (WPU) nanocomposite was synthesized from polyurethane and organoclay. The clay was organically modified with a swelling agent, namely, 1,12-diaminododecane. The nanocomposite was characterized using Fourier transform infrared (FT-IR) and gel permeation chromatography (GPC). The d-spacing of clay was determined by X-ray diffraction (XRD) and confirmed by transmission electron microscopy (TEM). XRD and TEM analyses indicated that clay retains a layer structure in the clay/waterborne polyurethane (WPU) nanocomposite. Consequently, these materials are an intercalated nanocomposite with a d-spacing of around 4 to 5 nm. FT-IR revealed that adding clay does not affect the synthesis of the waterborne polyurethane. GPC results indicated that molecular weight decreased as the clay content increased. The thermal properties of the nanocomposite were examined using a thermogravimetric analyzer (TGA). Results showed that adding clay increased the temperature of thermal degradation by 15°C.     

A self-healing hydrogel electrolyte towards all-in-one flexible supercapacitors

The self-healing electrolytes play an essential role in self-healing supercapacitors. Herein, poly (vinyl alcohol)/sulphuric acid (PVA/H₂SO₄) hydrogel electrolytes with self-healing properties are prepared, which has been achieved by dynamic hydrogen bonds between PVA chains. The obtained PVA hydrogel displays fast self-healing capability, reliable mechanical performance (stress at 0.29 MPa after stretching to 238%) and high ionic conductivity (57.8 mS cm^?1). Based on these excellent properties, an all-in-one self-healing supercapacitor is assembled by in situ polymerization of aniline on the surface of PVA/H₂SO₄ hydrogel electrolyte. The assembled all-in-one supercapacitor shows outstanding capacitance performance (specific capacitance 504 mF cm^?2 at current density of 0.2 mA cm^?2 and energy density 35 μWh cm^?2 at power density 100 μW cm^?2), good cycle stability (after 5000 cycles of charging and discharging, the capacitance retention rate is 77%), excellent flexibility and considerable self-healing performance (69% capacitance retention rate after the fifth self-healing cycle). This self-healing supercapacitor will promote the development of self-healing energy storage devices in wearable electronics.

     

Preparation of graphene nanosheets/SnO2 composites by pre-reduction followed by in-situ reduction and their electrochemical performances

The Graphene nanosheets/SnO₂ composites were synthesized using stannous chloride to restore the semi-reduction graphene oxide (SRGO) under a simple hydrothermal reduction procedure. First graphene oxide was pre-reduced by glucose for a certain time to get SRGO, which keeps the good water-solubility of graphite oxide (GO) and has a good conductivity like graphene nanosheets. The higher electrostatic attraction between SRGO and Sn²⁺ makes SnO₂ nanoparticles tightly anchor on the graphene sheets in the hydrothermal reduction process. The formation mechanism of the composite was investigated by SEM, TEM, XRD, AFM and Raman. Moreover, the electrochemical behaviors of the Graphene nanosheets/SnO₂ nanocomposites were studied by cyclic voltammogram, electrical impedance spectroscopy (EIS) and chronopotentiometry. Results showed that the Graphene nanosheets/SnO₂ composites have excellent supercapacitor performances: the specific capacitance reached 368 F g⁻¹ at a current density of 5 mA cm⁻², and the energy density was much improved to 184 Wh kg⁻¹ with a power density of 16 kW kg⁻¹, and capacity retention was more than 95% after cycling 500 cycles with a constant current density of 50 mA cm⁻². The experimental results and the thorough analysis described in this work not only provide a potential electrode material for supercapacitors but also give us a new way to solve the reunification of the graphene sheets.