• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    蔥葉一步法裂解制備多孔炭及其電容性能研究

    2016-11-22 07:31:23高利珍李雪蓮高麗麗李長(zhǎng)明
    新型炭材料 2016年5期
    關(guān)鍵詞:蔥葉炭化麗麗

    于 晶, 高利珍, 李雪蓮, 吳 超, 高麗麗,3, 李長(zhǎng)明

    (1.太原理工大學(xué) 環(huán)境科學(xué)與工程學(xué)院,山西 太原030024;2.西南大學(xué) 清潔能源與先進(jìn)材料研究所,重慶400715;3.太原理工大學(xué) 綠色能源材料與儲(chǔ)能系統(tǒng)實(shí)驗(yàn)室,山西 太原030024)

    ?

    蔥葉一步法裂解制備多孔炭及其電容性能研究

    于 晶1, 高利珍1, 李雪蓮1, 吳 超2, 高麗麗1,3, 李長(zhǎng)明2

    (1.太原理工大學(xué) 環(huán)境科學(xué)與工程學(xué)院,山西 太原030024;2.西南大學(xué) 清潔能源與先進(jìn)材料研究所,重慶400715;3.太原理工大學(xué) 綠色能源材料與儲(chǔ)能系統(tǒng)實(shí)驗(yàn)室,山西 太原030024)

    以蔥葉為炭前驅(qū)體,在不添加任何活化劑的條件下,炭化活化同時(shí)進(jìn)行,制備了孔徑分布主要集中于0.6~1.2 nm和3~5nm之間的蔥基多孔炭材料,并對(duì)其電容性能進(jìn)行研究。分別采用掃描電子顯微鏡(SEM)、場(chǎng)發(fā)射掃描電子顯微鏡(FE-SEM)、能量彌散X射線光譜(EDX)、火焰原子吸收光譜(FAAS)、X射線衍射(XRD)、熱重分析(TGA)和氮?dú)馕摳角€等方法表征了蔥基炭的形貌、成分、比表面積及孔徑分布等性能;通過(guò)循環(huán)伏安(CV)、交流阻抗(EIS)、恒流充放電(GCD)等電化學(xué)方法考察了材料的比電容和循環(huán)壽命等電化學(xué)性能。結(jié)果表明,蔥葉中本身含有的微量礦物質(zhì)如鈣、鉀等在其炭化的過(guò)程中同時(shí)起到了活化的作用。研究了不同溫度下(600~800 ℃)制備的多孔炭的性能,發(fā)現(xiàn)800 ℃條件下制得的樣品性能最佳,以微孔為主,介孔輔之,孔徑為0.6~1.2 nm的微分孔隙體積達(dá)2.608 cm-3/g/nm,3~5 nm的微分孔隙體積有0.144 cm-3g/nm,BET比表面積為551.7 m2/g,質(zhì)量比電容為158.6 F/g,有效面積電容可高達(dá)28.8 μF/cm2。這表明孔徑分布情況對(duì)多孔炭的電荷存儲(chǔ)能力有很重要的影響,此法也為提高“有效面積電容”提供了思路。

    多孔炭; 蔥葉; 一步炭化活化法; 有效面積電容

    1 Introduction

    With the increase of the environmental pollution and the scarcity of fossil fuels, the demand for clean energy sources is growing rapidly all around the world. Supercapacitor, as a kind of clean energy conversion and storage device, has attracted much attention owing to its high power density, long cycle life and high dynamic of charge propagation, which bridges the power/energy gap between traditional dielectric capacitor and battery[1-6]. Especially, electrical double-layer supercapacitors (EDLSs), draw much more attention owing to their simple charging mechanism, long cycling life and short charging time. Since pure physical charge accumulation occurs at the electrochemical interface between electrode and electrolyte during the charge/discharge process, EDLS is able to store and deliver energy at a relatively high rate[7-10]. Compared to batteries, supercapacitors have the advantages of high power density, long life expectancy, long shelf life, high efficiency, wide range of operating temperatures, environmental friendliness and safety. However, they also face challenges at the current stage of technology, such as low energy density, high cost and high self-discharging rate. Among the components of a supercapacitor, electrode materials dominate the performance of supercapacitors[11]. Therefore, developing new materials with improved performance is important to improve the property of supercapacitors[12]. In general, electrode materials of supercapacitors include three types[13,14]: carbon materials, conducting polymers, and metal oxides. Porous carbons have large surface areas, relatively good electrical conducting properties and the 3D porous network structure that ensures fast electronic and ionic conduction through charge/discharge process. Furthermore, porous carbons are considered as the most promising candidate materials for supercapacitors in industry owing to their moderate cost[3, 7, 15]. Generally, the synthesis of porous carbons includes two steps: carbonization and activation. Among various precursors, cheap and renewable biomass such as agricultural byproducts have attracted much attention owing to their low cost and environmental friendly properties[16-18]. Activation is a crucial procedure, which include physical and chemical activation. For these two methods, either high temperature or large amount of chemical agent is used, which require expensive equipments or bring about difficulty in post-treatment[19-25]. Though various porous carbons have been tried as electrode materials in supercapacitors, their applications are still limited owing to their complicated production processes[26]. As reported, natural constituents such as mineral substances in some kinds of leaves may replace the additional pore generators to create micropores, thereby simplifying the process[27,28]. Green onions are widely planted in China and could be stored in winter. However, during the storage, the leaves of green onions are usually withered and need to be discarded. Therefore, we reported a facile, cost-effective approach to synthesize porous carbon via one-step pyrolysis of the discarded green onion leaves without any additive. The reason might be that green onion leaves contain Ca and K that act as pore generators[27,28]. The pore sizes are mainly centered around 0.6-1.2 and 3-5 nm. Although the specific surface area and the mass specific capacitance for the green onion leave-derived carbons (GOLCs) are not so high, their “effective areal capacitance” is high, indicating that the proportion of their effective pores in GOLCs is high.

    2 Experimental

    2.1 Chemicals

    The green onions used in this study were directly obtained from the local farm. Nafion solution was purchased from Sigma. All other chemical reagents, such as hydrochloric acid (HCl, 36%), nitric acid (HNO3, 65%), perchloric acid (HClO4, 70%), hydrogen peroxide (H2O2, 30%) and potassium hydroxide (KOH, 98%), were purchased from Sinopharm Chemical Reagent Co. Ltd and used as received without any further purification. All the aqueous solutions were prepared with Millipore water having a resistivity of 18.2 MΩ (Purelab Classic Corp., USA).

    2.2 Synthesis of porous carbons

    The synthesis process of green onion leave-derived carbons (GOLCs) is shown in Fig. 1.

    Fig. 1 Schematic diagram for the synthesis of porous carbons from green onion leaves.

    The leaves of green onion were separated from the white stem, washed thoroughly with deionized water and dried at 60 ℃ in an oven over night. The dried leaves were crushed into powder. The carbonization and activation processes were carried out at one step. The dried leave powder was heated at 600-800 ℃ under the protection of argon for 2 h in a tubular furnace. The heating rate was 10 ℃/min. After cooled down to room temperature under argon, the green powder was totally turned into black color. The obtained products were washed thoroughly by deionized water and then dried in an oven over night. For comparison, some products were rinsed by a diluted hydrochloric solution (0.1 M).

    2.3 Electrochemical measurements

    Electrochemical characterizations were carried out in a three-electrode electrochemical system using Hg/HgO electrode and platinum foil as the reference and counter electrode, respectively. The GOLC powder was dispersed in water by sonication. Then the suspension was dripped on a glassy carbon electrode and coated by Nafion solution.

    All the electrochemical measurements were carried out on a CHI 660D electrochemical workstation (Shanghai Chenhua Co. Ltd, China) in 3 M KOH aqueous electrolyte solution at room temperature. Cyclic voltammetry (CV) curves were obtained between a potential range of -1.0-0.1 V at different scanning rates. The electrochemical impedance spectroscopy (EIS) was performed in a three-electrode system at 5 mV-alternating current-disturbance around the open circuit potential vs Hg/HgO. The scanning frequency was from 0.01 to 100 kHZ. The galvanostatic charge/discharges (GCD) were carried out under different current densities.

    The mass specific capacitance is calculated from GCD curves through equation (1) :

    (1)

    where “Cs” is the specific capacitance, “I” is the current, “m” is the active mass and “dv/dt” is the slope obtained from the discharge curve.

    Effective areal capacitance (Cea, μF/cm2) means the ratio of “mass specific capacitance (Cms, F/g)” and “BET surface area (A, m2/g)”, which is calculated by the equation (2).

    (2)

    2.4 Characterizations

    The morphology of GOLCs was observed by a JSM-6510LV (Japan) scanning electron microscope (SEM) and a JSM-7800F field-emission scanning electron microscope (FE-SEM, Japan). Elemental composition analysis was qualitatively measured by JSM-6510LV (Japan) energy dispersive X-ray spectroscopy (EDX) and quantitatively determined by WFX-110 flame atomic absorption spectrometry (FAAS). The samples were pretreated before FAAS measurement. Firstly, they were ground into powder and poured into an acid mixture of HNO3and HClO4, followed by heating and dissolving at a hot plate until most of water evaporated. Then H2O2was added to get rid of the residual acid. Through the treatment, minerals such as K and Ca could be totally dissolved from the samples, which could be used for FAAS measurements. The nitrogen adsorption and desorption isotherms at 77 K were measured using a Quantachrome Instruments (USA) Inc. Nova 1200e surface area and pore size analysis system. The specific surface area was calculated from the N2adsorption isotherm by applying the Brunauer-Emmett-Teller (BET) equation. In order to reflect the pore size distribution exactly, both Barrett-Joyner-Halenda (BJH) and Density functional theory (DFT) models were applied. BJH model is more suitable to mesopore analysis while DFT for micropore analysis. XRD patterns were obtained by a XRD-7000 (Japan). Thermogravimetric analysis (TGA) and differential thermogravimetric (DTG) analysis were carried out using with a Thermogravimetric Analyzer Q50 (USA).

    3 Results and discussion

    The morphology of all GOLCs prepared at different temperatures is shown in Fig. 2. From the SEM images (from 2a to 2f), all the samples prepared at different temperatures show similar fiber structure as the original leaves, implying that the macroscopical structure haven’t been changed during carbonization. However, mesopores and micropores could not be clearly observed under SEM, which might be caused by the low magnification and resolution of SEM. The GOLC prepared at 800 ℃ (GOLC-800) under FE-SEM is shown in Fig. 2g-h, which reveals that more tiny pores can be observed, but still not quite clear. This might be because some of the pores may be hidden by the original mineral substances that are uniformly distributed in green onion leaves.

    The pore structure could be further verified by nitrogen adsorption-desorption isotherms as shown in Fig. 3. An obvious hysteresis loop can be observed in the isotherms in Fig. 3a at the relative pressure from 0.4 to 0.9. The hysteresis loop can be categorized as H4 type, revealing that mesopores exist in the samples[28,29]. The specific surface areas for different GOLCs prepared at 600, 700 and 800 ℃, abbreviated as GOLC-600, GOLC-700 and GOLC-700, are calculated with standard BET method to be and respectively 230.5,348.4 and 551.7 m2/g, respectively. Fig. 3b-d depict the pore size distributions of GOLCs with the two models, which show bimodal distribution of micropores and mesopores. Through calculation, the differential pore volumes of micropores (0.6-1.2 nm) are 1.432, 1.449 and 2.608 cm-3/g/nm for GOLC-600, GOLC-700 and GOLC-800, respectively. Furthermore, most of the micropores are centered around 0.6-0.8 nm. Micropores have a high surface area to volume ratio and contribute more to surface area when present in significant amounts. Some studies have reported that pore sizes around 0.7 nm may be a suitable dimension for aqueous electrolyte,which could match the dimension of the aqueous ion[2, 32,33]. And the corresponding differential pore volumes of mesopores (3 to 5 nm) are 0.016, 0.071 and 0.144 cm-3/g/nm for GOLC-600, GOLC-700 and GOLC-800, respectively. As reported[30], mesopores play a significantly important role to obtain an ideal capacitor behavior, because they can not only contribute to the surface area but also provide wide transport channels for adsorbate accessibility[31]. Both the differential micropore volume and differential mesopore volume for GOLC-800 are the highest among the three samples, implying that high activation temperature is favorable for the generation of pores. Therefore, GOLC-800 is the most excellent material among the three, followed by GOLC-700 and then GOLC-600, if it is judged merely from the pore size distributions and BET surface areas.

    Fig. 2 (a-f) SEM and (g-h) FESEM images of green onion leave-derived carbons prepared at different temperatures: (a-b) 600 ℃, (c-d) 700 ℃ and (e-h) 800 ℃.

    The elements and their relative contents in the GOLC-800 were also determined by EDX as shown in Fig. 4a. It is seen that carbon (C) is the most prominent ingredient, implying that the green onion has been well carbonized. Trace of inorganic elements such as oxygen (O), sulphur (S), chlorine (Cl) and phosphorus (P) can be observed as shown in Fig. 4a. The existing of oxygen (O) implies that there are lots of oxygen-groups on the surface of the carbon. Furthermore, some mineral substances can be as well detected, such as calcium (Ca) and potassium (K). Since no element addition was involved during the carbonization of GOLC-800, it can be inferred that all the mineral substances originate directly from the green onion leaves.

    Fig. 3 (a) Nitrogen adsorption-desorption isotherms for green onion leave-derived carbons prepared at different temperatures; (b-d) pore size distributions with the BJH and DFT models.

    Fig. 4 (a) Images of EDX analysis and (b) XRD patterns for green onion leave-derived carbon at 800 ℃.

    To further verify the content of these mineral substances, TGA measurement of original green onion leaves was also carried out as shown in Fig. 5.

    Stage I from 25 to approx. 200 ℃ might correspond to the elimination water including free and bonded water, and the total content of water in green onion is 15 wt%. The main pyrolysis of green onion occurs at Stage II (200-300 ℃) and Stage III (300-500 ℃), which show highest weight loss. Stage II may be correlated to the decomposition of carbohydrates and proteins[27]while stage III to cellulose and hemicellulose[34]. The weight loss for stage II and III is approximately 55% in general. When the temperature is higher than 500 ℃ (stage IV), only a 5%-8% weight reduction happens until 800 ℃,which might be caused by the decomposition of the small amount of lignin contained in green onion[34]. The residual content after Stage IV is above 20%, part of which may be due to the large amount of minerals such as Ca, K originally present in green onion leaves.

    The XRD patterns of GOLCs in Fig. 4b could further confirm the existence of mineral substances. The upper line in Fig. 4b represents the GOLC-800 that was washed only with pure water, from which, two sharp peaks near 28° and 33° could be seen obviously; however, after the GOLC-800 was rinsed by diluted HCl solution, these two peaks disappeared as shown in the lower line. Through comparison to the standard spectrum diagrams, the sharp peaks might be attributed to CaC2. After rinsing with HCl, CaC2might reacts with in water. Furthermore, a broad peak near 2θ=25°can be seen in both lines, corresponding to the crystalline graphite. As reported[27,28], Ca and K salts can be acted as pore generators to create pores during the synthesis. Nakagawa[35]reported that more mesopores and micropores could be obtained in the porous carbons by adding some calcium compound into the raw material before activation. Raymundo also illustrated that the presence of K derivatives in carbon precursor played the same role as additives of chemical pore generators during the activation[27].

    Fig. 5 TGA and (DTG) analysis of green onion leaves under a nitrogen atmosphere (heating rate: 10 ℃/min).

    To quantitatively analyze the contents of mineral substances (K, Ca), FAAS was applied. Three different samples were measured, dried green onion leaves prepared by drying green onion leaves under 60 ℃ at vacuum oven for 12 h, GOLC-800 and GOLC-800 rinsed by HCl solution. The results are listed in Table 1, which reveal that the original contents of K and Ca in dried green onion leaves are 20.5 and 3.5 mg/g, respectively, which are similar to the reported results[28]. After the carbonization at 800 ℃, the contents of K and Ca increase to 42.7 and 7.3 mg/g, respectively. The increase of their relative contents in the samples might be attributed to pyrolysis of carbohydrates and proteins, namely, the loss of H, O and other elements. These results agree well with the TGA conclusions as shown in Fig. 5. Compared with the amount of the activating agents added in chemical activation, the contents of K and Ca are very low. However, as reported by Biswal[28], natural constituents such as mineral substances in biomass are distributed uniformly. So despite the very few amounts, they are very effective to create pores in activation. In this work, the total content of K and Ca in GOLC-800 is 50 mg/g, so they could play an important role to generate pores in carbonization as activating agents. This is why no more external activating agents are needed. After the GOLC samples were thoroughly rinsed in HCl solution, the K and Ca were removed to an extent too little to be detected.

    Table 1 Contents of K and Ca in dried green onion leaves, GOLC-800 and GOLC-800 rinsed by HCl.

    Electrochemical behaviors of GOLCs prepared under different temperatures were measured in 3 M KOH aqueous electrolyte, as shown in Fig. 6 and Fig. 7. To measure whether the residual K and Ca in GOLC-800 have great effect on capacitance, the GOLC-800 samples were thoroughly rinsed by HCl, as shown in Fig 6a. The XRD results in Fig 4b have shown that materials such as Ca could be gotten rid of through rinsing with HCl. However, it could be obviously seen that CV curves of GOLC-800 and GOLC-800 rinsed by HCl are similar, implying that the mineral substances as K and Ca in GOLC have little effects. Thus, GOLCs were just washed by deionized water and measured in the following samples.

    Fig. 6b is the galvanostatic charge/discharge curve at 0.2 A/g of GOLCs, linear and nearly symmetrical curves could be seen in all samples, confirming that the product has excellent electrochemical reversibility and charge/discharge properties. Comparison of the three samples at the same charge/discharge current density of 0.2 A/g, discharge time of GOLC-800 is nearly 870 s, and GOLC-700 and GOLC-600 is 570 and 520 s, respectively, implying that GOLC-800 has better electrochemical performance than GOLC-600 and GOLC-700. The mass specific capacitances for GOLC-800, GOLC-700 and GOLC-600 at a current density of 0.2 A/g calculated from equation (1) are 158.6,104.2 and 94.8 F/g, respectively. The higher mass specific capacitance for GOLC-800 may be ascribed to its larger specific surface area and higher differential pore volume[36]. Actually, this capacitance value is relatively higher than those of other electrode materials for supercapacitor application from biomass precursor[8,37]. Fig 6c is the galvanostatic charge/discharge curves of GOLC-800 at different current densities. It can be seen that the capacitances drastically change for GOLC-600, GOLC-700 and GOLC-800 when the current density increases from 0.2 to 5.0 A/g as shown in Fig. 6d. This can be explained as follows[38]. At lower current densities, ions can be transported and diffused into the pores easily, which results in higher capacitance. However, when the current density increases, ions cannot be easily diffused into the pores so that the effective double layers are formed at the surface of the electrode. Hence, the capacitance at high current densities are low.

    Fig. 6 Measurements of GOLCs’ electrochemical behavior.

    Fig. 7a and Fig. 7b depict the cyclic voltammetry curves of GOLC-800 at different scanning rates. At lower scanning rate such as 2 mV/s, a redox hump could be observed betwwen -0.15-0.25 V, which might be casued by oxygen-groups reaction at the carbon surface[39]. This Faradaic redox reaction also contributes to the capacitance. However, in the whole scaning rang from -1.0 to 0.1 V, the CV curves represent nearly rectangular shape, revealing an ideal capacitance behavior and the charge/discharge process is nearly reversible[23,40].With the increasing of scanning rate, there is almost no deviation from rectangular shape in CV curves, implying the low ohmic polarization and high electrolyte ion transfer rate. At the same time, when the direction of the scanning rate changes, current responses quickly, implying the fast kinetics of the double layer formation.

    Electrochemical impedance spectrometry (EIS) is a steady state technique with small potential variation, which is more reliable for measuring the capacitance. The sloping line in the range of low frequency corresponds to the diffusive resistance. In Fig. 7c, the Nyquist plots for all the samples are dominated by nearly vertical trend capacitive lines in the range of low frequency which indicate capacitive behavior according to the equivalent circuit theory and could be attributed to the capacitive properties. However, the sloping line for GOLC-800 is more vertical than that for GOLC-700 and GOLC-600, revealing that GOLC-800 represents low diffusive resistance and high capacitance. In the range of high frequency, no obvious semicircle could be observed, implying that the intrinsic resistance of the active material is relatively small, which agree well with the results in Fig. 7a, b.

    Furthermore, the GOLC-800 shows an excellent cycling stability as shown in Fig.7d. The mass specific capacitance still remains 96% of the initial after 5 000 galvanostatic charge/discharge cycles at a current density of 10 A/g.

    Fig. 7 Measurements of GOLCs’ electrochemical behavior.

    Some other carbons synthesized from biomass materials are compared with ours as shown in Table 2. Rice husk[41], firewood[25], bamboo[42], bean dregs[43]and many other biomass materials were applied as precursor. Mass specific capacitance is an important factor that should be considered in practical application. However, for some small electronic devices, effective areal capacitance is very important in supercapacitor applications[44,45]. Compared with other biomass derived carbons, BET surface area and mass specific capacitance of GOLC prepared in this work might not be that high, but the effective areal capacitance is much high, reaching 28.8 μF/cm2at 0.2 A/g.

    Table 2 Comparison of carbon synthesized from biomass materials.

    4 Conclusions

    Green onion leaves derived carbons (GOLCs) were prepared by a simple carbonization without any external additives. Three kinds of GOLCs were prepared at different carbonization temperatures: GOLC-600, GOLC-700 and GOLC-800. All the carbons have a bimodal pore distribution of micropores and mesopores, and GOLC-800 has highest differential pore volume in both micropore and mesopore range. GOLC-800 shows the highest mass specific capacitance and specific surface area among the three.More importantly, the effective areal capacitance of GOLC-800 could reach 28.8 μF /cm2at 0.2 A/g,which is the highest among the samples reported. This is mainly due to the suitable pore distribution GOLC-800 has. In addition, the surface functional groups, especially oxygen groups on the surface of GOLC-800 induce pseudocapacitance, which could contribute to the capacitance. From XRD, EDX, TGA and FAAS analysis, Ca and K could be detected. These original mineral substances in green onion leaves act as pore-generator during the carbonization. The porous carbons derived from green onion leaves are promising electrode materials for supercapacitors, especially for small devices, in which a high areal capacitance of the electrode material is required.

    [1] Kandalkar S G, Dhawale D S, Kim C K, et al. Chemical synthesis of cobalt oxide thin film electrode for supercapacitor application[J]. Synthetic Metals, 2010, 160(11): 1299-1302.

    [2] Largeot C, Portet C, Chmiola J, et al. Relation between the ion size and pore size for an electric double-layer capacitor[J]. Journal of the American Chemical Society, 2008, 130(9): 2730-2731.

    [3] Zhang L L, Zhao X S. Carbon-based materials as supercapacitor electrodes[J]. Chemical Society Reviews, 2009, 38(9): 2520-2531.

    [4] Li Y F, Liu Y Z, Zhang W K, et al. Green synthesis of reduced graphene oxide paper using Zn powder forsupercapacitors[J]. Materials Letters, 2015, 157: 273-276.

    [5] Miller J R, Simon P. Electrochemical capacitors for energy management[J]. Science Magazine, 2008, 321(5889): 651-652.

    [6] Winter M, Brodd R J. What are batteries, fuel cells, and supercapacitors?[J]. Chemical Reviews, 2004, 104(10): 4245-4270.

    [7] Pandolfo A G, Hollenkamp A F. Carbon properties and their role in supercapacitors[J]. Journal of Power Sources, 2006, 157(1): 11-27.

    [8] Stoller M D, Park S, Zhu Y, et al. Graphene-based ultracapacitors[J]. Nano Letters, 2008, 8(10): 3498-3502.

    [9] Wang Y, Shi Z, Huang Y, et al. Supercapacitor devices based on graphene materials[J]. The Journal of Physical Chemistry C, 2009, 113(30): 13103-13107.

    [10] K?tz R, Carlen M. Principles and applications of electrochemical capacitors[J]. Electrochimica Acta, 2000, 45(15): 2483-2498.

    [11] Wang G, Zhang L, Zhang J. A review of electrode materials for electrochemical supercapacitors[J]. Chemical Society Reviews, 2012, 41(2): 797-828.

    [12] Aricò A S, Bruce P, Scrosati B, et al. Nanostructured materials for advanced energy conversion and storage devices[J]. Nature Materials, 2005, 4(5): 366-377.

    [13] Choi D, Kumta P N. Nanocrystalline TiN derived by a two-step halide approach for electrochemical capacitors[J]. Journal of the Electrochemical Society, 2006, 153(12): A2298-A2303.

    [14] Lee H, Cho M S, Kim I H, et al. RuOx/polypyrrole nanocomposite electrode for electrochemical capacitors[J]. Synthetic Metals, 2010, 160(9): 1055-1059.

    [15] Shi H. Activated carbons and double layer capacitance[J]. Electrochimica Acta, 1996, 41(10): 1633-1639.

    [16] Elmouwahidi A, Zapata-Benabithe Z, Carrasco-Marín F, et al. Activated carbons from KOH-activation of argan (Argania spinosa) seed shells as supercapacitor electrodes[J]. Bioresource Technology, 2012, 111: 185-190.

    [17] Li X, Xing W, Zhuo S, et al. Preparation of capacitor’s electrode from sunflower seed shell[J]. Bioresource Technology, 2011, 102(2): 1118-1123.

    [18] Bao L, Li X. Towards textile energy storage from cotton T-shirts[J]. Advanced Materials, 2012, 24(24): 3246-3252.

    [19] Balathanigaimani M S, Shim W G, Lee M J, et al. Highly porous electrodes from novel corn grains-based activated carbons for electrical double layer capacitors[J]. Electrochemistry Communications, 2008, 10(6): 868-871.

    [21] Rufford T E, Hulicova-Jurcakova D, Fiset E, et al. Double-layer capacitance of waste coffee ground activated carbons in an organic electrolyte[J]. Electrochemistry Communications, 2009, 11(5): 974-977.

    [22] Rufford T E, Hulicova-Jurcakova D, Khosla K, et al. Microstructure and electrochemical double-layer capacitance of carbon electrodes prepared by zinc chloride activation of sugar cane bagasse[J]. Journal of Power Sources, 2010, 195(3): 912-918.

    [23] Rufford T E, Hulicova-Jurcakova D, Zhu Z, et al. Nanoporous carbon electrode from waste coffee beans for high performance supercapacitors[J]. Electrochemistry Comm-unications, 2008, 10(10): 1594-1597.

    [24] Subramanian V, Luo C, Stephan A M, et al. Supercapacitors from activated carbon derived from banana fibers[J]. The Journal of Physical Chemistry C, 2007, 111(20): 7527-7531.

    [25] Wu F C, Tseng R L, Hu C C, et al. Effects of pore structure and electrolyte on the capacitive characteristics of steam-and KOH-activated carbons for supercapacitors[J]. Journal of Power Sources, 2005, 144(1): 302-309.

    [26] Wang Q, Yan J, Wang Y, et al. Template synthesis of hollow carbon spheres anchored on carbon nanotubes for high rate performance supercapacitors[J]. Carbon, 2013, 52: 209-218.

    [28] Biswal M, Banerjee A, Deo M, et al. From dead leaves to high energy density supercapacitors[J]. Energy & Environmental Science, 2013, 6(4): 1249-1259.

    [29] Fan Z, Qi D, Xiao Y, et al. One-step synthesis of biomass-derived porous carbon foam for high performance supercapacitors[J]. Materials Letters, 2013, 101: 29-32.

    [30] Thomberg T, Kurig H, J?nes A, et al. Mesoporous carbide-derived carbons prepared from different chromium carbides[J]. Microporous and Mesoporous Materials, 2011, 141(1): 88-93.

    [31] Wang Y, Xia Y. Electrochemical capacitance characterization of NiO with ordered mesoporous structure synthesized by template SBA-15[J]. Electrochimica Acta, 2006, 51(16): 3223-3227.

    [32] Raymundo-Pinero E, Kierzek K, Machnikowski J, et al. Relationship between the nanoporous texture of activated carbons and their capacitance properties in different electrolytes[J]. Carbon, 2006, 44(12): 2498-2507.

    [33] Ania C O, Khomenko V, Raymundo-Piero E, et al. The large electrochemical capacitance of microporous doped carbon obtained by using a zeolite template[J]. Advanced Functional Materials, 2007, 17(11): 1828-1836.

    [34] Qu T, Guo W, Shen L, et al. Experimental study of biomass pyrolysis based on three major components: hemicellulose, cellulose, and lignin[J]. Industrial & Engineering Chemistry Research, 2011, 50(18): 10424-10433.

    [35] Nakagawa K, Mukai S R, Suzuki T, et al. Gas adsorption on activated carbons from PET mixtures with a metal salt[J]. Carbon, 2003, 41(4): 823-831.

    [36] Kim C, Lee J W, Kim J H, et al. Feasibility of bamboo-based activated carbons for an electrochemical supercapacitor electrode[J]. Korean Journal of Chemical Engineering, 2006, 23(4): 592-594.

    [37] Hao G P, Mi J, Li D, et al. A comparative study of nitrogen-doped hierarchical porous carbon monoliths as electrodes for supercapacitors[J]. New Carbon Materials, 2011, 26: 197-203.

    [38] Chen M D, Kang X Y, Wumaier T, et al. Preparation of activated carbon from cotton stalk and its application in supercapacitor[J]. Solid State Electrochem, 2013, 17: 1005-1012.

    [39] Jang Y, Jo J, Choi Y M, et al. Activated carbon nanocomposite electrodes for high performance supercapacitors[J]. Electrochimica Acta, 2013, 102: 240-245.

    [40] Basri N H, Dolah B N M. Physical and electrochemical properties of supercapacitor electrodes derived from carbon nanotube and biomass carbon[J]. Int J Electrochem Sci, 2013, 8: 257-273.

    [41] Guo Y, Qi J, Jiang Y, et al. Performance of electrical double layer capacitors with porous carbons derived from rice husk[J]. Materials Chemistry and Physics, 2003, 80(3): 704-709.

    [42] Kim Y J, Lee B J, Suezaki H, et al. Preparation and characterization of bamboo-based activated carbons as electrode materials for electric double layer capacitors[J]. Carbon, 2006, 44(8): 1592-1595.

    [43] Ruan C, Ai K, Lu L. Biomass-derived carbon materials for high-performance supercapacitor electrodes[J]. RSC Advances, 2014, 4(58): 30887-30895.

    [44] McDonough J R, Choi J W, Yang Y, et al. Carbon nanofiber supercapacitors with large areal capacitances[J]. Applied Physics Letters, 2009, 95(24): 243109.

    [45] Zheng G, Hu L, Wu H, et al. Paper supercapacitors by a solvent-free drawing method[J]. Energy Environ Sci, 2011, 4(9): 3368-3373.

    Porous carbons produced by the pyrolysis of green onion leaves and their capacitive behavior

    YU Jing1, GAO Li-zhen1, LI Xue-lian1, WU Chao2, GAO Li-li1,3, LI Chang-ming2

    (1.SchoolofEnvironmentalScienceandEngineering,TaiyuanUniversityofTechnology,Taiyuan030024,China;2.InstituteforCleanEnergy&AdvancedMaterials,SouthwestUniversity,Chongqing400715,China;3.Labofgreenenergymaterialsandstoragesystems,TaiyuanUniversityofTechnology,Taiyuan030024,China)

    Porous carbons were prepared by the simple carbonization of green onion leaves at temperatures from 600 to 800 ℃ and used as the electrode materials of supercapacitors. SEM, FESEM, EDX, AAS, XRD, TGA and nitrogen adsorption were used to characterize their morphology, pore structure and surface elemental composition. Cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge were carried out to evaluate their specific capacitance, resistance and cycling life. Results showed that the initial mineral elements present in the leaves such as calcium (Ca) and potassium (K) play an activating role during the carbonization. All samples have a bimodal pore distribution of micropores (mainly 0.6-1.2 nm) and mesopores (mainly 3-5 nm). The carbon prepared at 800 ℃ had the highest surface area of 551.7 m2/g, a specific capacitance of 158.6 F/g at 0.2 A/g and an effective areal capacitance of 28.8 μF/cm2. The effective areal capacitance of the carbon prepared at 800 ℃ is higher than of most porous carbons reported in the literature, which is ascribed to its pore size distribution that favors ion access to its pores.

    Porous carbon; Green onion leaves; One-step carbonization and activation; Effective areal capacitance

    GAO Li-li, Post-doctor, Lecturer. E-mail: gaolili@tyut.edu.cn

    山西省青年科技研究基金資助項(xiàng)目(2013021011-3);山西省留學(xué)人員科研基金資助項(xiàng)目(2013-041);太原理工大學(xué)人才引進(jìn)資助項(xiàng)目(tyut-rc201110a).

    高麗麗,博士后,講師. E-mail:gaolili@tyut.edu.cn

    1007-8827(2016)05-0475-10

    X712

    A

    10.1016/S1872-5805(16)60026-4

    Receiveddate: 2016-06-10;Reviseddate: 2016-07-28

    Foundation: Shanxi Province Science Foundation for Youths (2013021011-3); Shanxi Scholarship Council of China (2013-041); Project for Importing Talent of Taiyuan University of Technology(tyut-rc201110a).

    English edition available online ScienceDirect ( http:www.sciencedirect.comsciencejournal18725805 ).

    猜你喜歡
    蔥葉炭化麗麗
    快點(diǎn) 快點(diǎn)
    畫一畫
    水稻秸稈制備生物制活性碳
    市政污泥炭化時(shí)間與溫度研究
    安徽建筑(2018年4期)2019-01-29 02:16:14
    賣 蔥
    I love my family
    賴麗麗
    廚房那些事兒:廢棄蔥葉怎么吃
    食品與健康(2015年4期)2015-09-10 07:22:44
    蔥葉比蔥白更營(yíng)養(yǎng)
    健康必讀(2015年3期)2015-06-01 00:06:27
    為什么賠了
    欧美亚洲 丝袜 人妻 在线| 亚洲中文日韩欧美视频| 国产精品久久久久久精品古装| 在线观看免费视频网站a站| 19禁男女啪啪无遮挡网站| 69av精品久久久久久 | 看免费av毛片| 建设人人有责人人尽责人人享有的| 日韩 欧美 亚洲 中文字幕| 午夜福利免费观看在线| 亚洲国产av影院在线观看| 国产精品一区二区免费欧美 | 国产熟女午夜一区二区三区| 亚洲色图综合在线观看| 老熟妇仑乱视频hdxx| 国产欧美日韩一区二区三 | 午夜日韩欧美国产| 91字幕亚洲| 十八禁网站免费在线| 免费观看人在逋| 操美女的视频在线观看| 一本综合久久免费| 国产精品麻豆人妻色哟哟久久| 免费高清在线观看日韩| 日本撒尿小便嘘嘘汇集6| 免费一级毛片在线播放高清视频 | 国产91精品成人一区二区三区 | 可以免费在线观看a视频的电影网站| 精品少妇内射三级| 成年av动漫网址| 国产欧美日韩精品亚洲av| 超色免费av| 国产精品 欧美亚洲| 五月天丁香电影| 老熟女久久久| 美女脱内裤让男人舔精品视频| 午夜老司机福利片| 日日爽夜夜爽网站| 99久久人妻综合| 性高湖久久久久久久久免费观看| 两人在一起打扑克的视频| 午夜日韩欧美国产| 亚洲欧美色中文字幕在线| 国产av精品麻豆| 国产成人av教育| 一区二区三区四区激情视频| 韩国精品一区二区三区| 亚洲九九香蕉| 老司机福利观看| 亚洲va日本ⅴa欧美va伊人久久 | 一本色道久久久久久精品综合| 午夜91福利影院| 伊人久久大香线蕉亚洲五| 国产一区二区激情短视频 | 日本欧美视频一区| 一级,二级,三级黄色视频| 国产精品欧美亚洲77777| 97人妻天天添夜夜摸| 精品视频人人做人人爽| 亚洲精品日韩在线中文字幕| 亚洲精品久久午夜乱码| 乱人伦中国视频| 一个人免费在线观看的高清视频 | 老汉色∧v一级毛片| 国产精品二区激情视频| 亚洲国产av新网站| 超碰成人久久| 久久精品国产亚洲av香蕉五月 | 成年美女黄网站色视频大全免费| 多毛熟女@视频| 国产精品免费视频内射| 深夜精品福利| 精品久久久久久电影网| 女人爽到高潮嗷嗷叫在线视频| 日本五十路高清| 精品国产乱码久久久久久男人| 国产区一区二久久| 丝袜美足系列| 亚洲一区中文字幕在线| 国产精品国产av在线观看| 中文字幕人妻丝袜一区二区| 欧美日韩成人在线一区二区| 真人做人爱边吃奶动态| 在线观看人妻少妇| 男女之事视频高清在线观看| 免费久久久久久久精品成人欧美视频| 日韩一区二区三区影片| 大香蕉久久网| 少妇的丰满在线观看| 人妻人人澡人人爽人人| 日韩 欧美 亚洲 中文字幕| 老鸭窝网址在线观看| 黑人猛操日本美女一级片| 多毛熟女@视频| 国产视频一区二区在线看| kizo精华| 国产成人一区二区三区免费视频网站| 热99国产精品久久久久久7| 国产日韩欧美在线精品| 桃红色精品国产亚洲av| 少妇猛男粗大的猛烈进出视频| 黑人巨大精品欧美一区二区蜜桃| 国产福利在线免费观看视频| 久久综合国产亚洲精品| 少妇粗大呻吟视频| 久久久精品免费免费高清| 视频区欧美日本亚洲| 80岁老熟妇乱子伦牲交| 丁香六月天网| 精品人妻在线不人妻| 性色av乱码一区二区三区2| 国产精品偷伦视频观看了| 亚洲精品国产色婷婷电影| 亚洲精品国产av成人精品| 国产视频一区二区在线看| 十八禁高潮呻吟视频| 91麻豆精品激情在线观看国产 | 免费高清在线观看日韩| 免费看十八禁软件| 国产97色在线日韩免费| 国产99久久九九免费精品| 欧美日韩精品网址| 99国产极品粉嫩在线观看| 亚洲,欧美精品.| 国产成人精品无人区| 日本撒尿小便嘘嘘汇集6| 久久99热这里只频精品6学生| 9热在线视频观看99| 十八禁高潮呻吟视频| 在线天堂中文资源库| 亚洲黑人精品在线| 国产人伦9x9x在线观看| 免费在线观看影片大全网站| 老司机影院毛片| 久久久久久亚洲精品国产蜜桃av| 女性被躁到高潮视频| 久久精品国产a三级三级三级| 国产成人精品在线电影| 日韩有码中文字幕| 啦啦啦中文免费视频观看日本| 婷婷成人精品国产| 18禁国产床啪视频网站| 交换朋友夫妻互换小说| 色婷婷av一区二区三区视频| 国产一区二区 视频在线| av免费在线观看网站| 国产成人系列免费观看| 视频区欧美日本亚洲| 69精品国产乱码久久久| av天堂久久9| 国产精品1区2区在线观看. | 久久久精品国产亚洲av高清涩受| 午夜免费鲁丝| 亚洲欧美激情在线| 一区福利在线观看| 欧美激情高清一区二区三区| 操出白浆在线播放| 一本久久精品| 午夜福利,免费看| 69精品国产乱码久久久| 两性午夜刺激爽爽歪歪视频在线观看 | 日韩制服骚丝袜av| 亚洲五月色婷婷综合| 十八禁网站免费在线| 亚洲伊人久久精品综合| 啦啦啦啦在线视频资源| 在线看a的网站| 久久久久久久久免费视频了| 亚洲成人免费av在线播放| 美女大奶头黄色视频| 91老司机精品| 国产xxxxx性猛交| 日韩大码丰满熟妇| 两性午夜刺激爽爽歪歪视频在线观看 | 狂野欧美激情性xxxx| 日韩一区二区三区影片| 人人妻人人澡人人爽人人夜夜| 国产成人欧美在线观看 | 欧美国产精品va在线观看不卡| 国产又色又爽无遮挡免| 99热网站在线观看| 美女视频免费永久观看网站| 精品国产一区二区三区久久久樱花| 日本猛色少妇xxxxx猛交久久| 亚洲精品在线美女| 一个人免费在线观看的高清视频 | 成人黄色视频免费在线看| 日韩欧美一区视频在线观看| videosex国产| 日本一区二区免费在线视频| 人人妻人人添人人爽欧美一区卜| 亚洲熟女毛片儿| 啦啦啦免费观看视频1| 国产一区二区三区综合在线观看| 嫁个100分男人电影在线观看| 欧美另类一区| av免费在线观看网站| 在线永久观看黄色视频| 午夜福利在线观看吧| 亚洲国产中文字幕在线视频| 黄色视频在线播放观看不卡| 精品国产一区二区三区四区第35| 日本a在线网址| 大码成人一级视频| 搡老熟女国产l中国老女人| 国产日韩欧美亚洲二区| 亚洲九九香蕉| 老司机午夜福利在线观看视频 | 国产99久久九九免费精品| 少妇精品久久久久久久| 别揉我奶头~嗯~啊~动态视频 | 91精品三级在线观看| 一本色道久久久久久精品综合| 亚洲三区欧美一区| 欧美激情高清一区二区三区| 久久青草综合色| 国产日韩欧美在线精品| 国产一区二区在线观看av| 午夜激情av网站| 欧美日韩中文字幕国产精品一区二区三区 | 国产欧美日韩综合在线一区二区| 少妇 在线观看| 成人亚洲精品一区在线观看| 精品第一国产精品| 久久狼人影院| 最新在线观看一区二区三区| 国产一级毛片在线| 亚洲精华国产精华精| 黑人操中国人逼视频| 亚洲视频免费观看视频| 亚洲精品乱久久久久久| 久久人人97超碰香蕉20202| 最近最新免费中文字幕在线| 老司机影院成人| 精品人妻熟女毛片av久久网站| 国产成人欧美在线观看 | 麻豆乱淫一区二区| 国产精品久久久久久人妻精品电影 | 天天躁日日躁夜夜躁夜夜| 亚洲成人国产一区在线观看| √禁漫天堂资源中文www| 成人国产一区最新在线观看| 中文欧美无线码| 女性被躁到高潮视频| 女性生殖器流出的白浆| 国产精品一区二区在线不卡| 精品亚洲成a人片在线观看| 黄片大片在线免费观看| a 毛片基地| 国产男女超爽视频在线观看| 免费在线观看日本一区| 一本一本久久a久久精品综合妖精| 首页视频小说图片口味搜索| 亚洲av成人不卡在线观看播放网 | 伊人久久大香线蕉亚洲五| 日韩大码丰满熟妇| 日韩 亚洲 欧美在线| 国产一区二区三区在线臀色熟女 | 叶爱在线成人免费视频播放| 国产成人免费无遮挡视频| 久久精品aⅴ一区二区三区四区| 亚洲伊人久久精品综合| 成人国产一区最新在线观看| 中文字幕人妻熟女乱码| 超碰97精品在线观看| av网站免费在线观看视频| 91精品伊人久久大香线蕉| 他把我摸到了高潮在线观看 | av不卡在线播放| 国产三级黄色录像| 啦啦啦中文免费视频观看日本| 欧美变态另类bdsm刘玥| 国产激情久久老熟女| av在线app专区| 国产一区二区三区av在线| 一边摸一边抽搐一进一出视频| 免费高清在线观看日韩| 精品高清国产在线一区| 啦啦啦 在线观看视频| 正在播放国产对白刺激| 久久精品aⅴ一区二区三区四区| 国产97色在线日韩免费| 精品人妻一区二区三区麻豆| 亚洲国产av新网站| 成人国产一区最新在线观看| 国产极品粉嫩免费观看在线| 老汉色∧v一级毛片| 视频在线观看一区二区三区| 美女国产高潮福利片在线看| 大型av网站在线播放| 午夜日韩欧美国产| 成人亚洲精品一区在线观看| 91精品伊人久久大香线蕉| 99精品欧美一区二区三区四区| 亚洲avbb在线观看| 啦啦啦免费观看视频1| 99久久精品国产亚洲精品| 丝袜在线中文字幕| 一区在线观看完整版| 狂野欧美激情性bbbbbb| 欧美精品一区二区大全| 99九九在线精品视频| 岛国毛片在线播放| 亚洲精品av麻豆狂野| 亚洲国产精品999| 美女扒开内裤让男人捅视频| 国产日韩欧美在线精品| 久久久久国产一级毛片高清牌| 精品人妻1区二区| 99热国产这里只有精品6| 热re99久久精品国产66热6| 男女边摸边吃奶| 老司机亚洲免费影院| 午夜福利在线免费观看网站| 国产成人a∨麻豆精品| 一本一本久久a久久精品综合妖精| 久久久精品94久久精品| 一区二区日韩欧美中文字幕| 免费久久久久久久精品成人欧美视频| 精品一品国产午夜福利视频| 日本猛色少妇xxxxx猛交久久| 午夜影院在线不卡| 国产男人的电影天堂91| 精品国产一区二区三区四区第35| 久久久国产一区二区| 国产一区有黄有色的免费视频| 性少妇av在线| 日本91视频免费播放| 国产成人av教育| 国产欧美日韩一区二区三区在线| 一进一出抽搐动态| 黑人猛操日本美女一级片| 午夜免费成人在线视频| 国产成人一区二区三区免费视频网站| 国产深夜福利视频在线观看| 日韩一卡2卡3卡4卡2021年| 午夜视频精品福利| 成年人黄色毛片网站| 亚洲中文日韩欧美视频| 在线精品无人区一区二区三| 啦啦啦中文免费视频观看日本| 午夜影院在线不卡| 美女主播在线视频| 久久久久久久国产电影| 国产国语露脸激情在线看| 黄色 视频免费看| 久久精品亚洲av国产电影网| 性色av一级| 亚洲人成电影观看| 婷婷色av中文字幕| 亚洲人成电影免费在线| 999久久久国产精品视频| 在线观看免费午夜福利视频| 黑人巨大精品欧美一区二区蜜桃| 99热网站在线观看| 97在线人人人人妻| 少妇的丰满在线观看| 女人高潮潮喷娇喘18禁视频| 女人精品久久久久毛片| 国产野战对白在线观看| 一本—道久久a久久精品蜜桃钙片| 自线自在国产av| 国产色视频综合| 妹子高潮喷水视频| 国产欧美日韩一区二区精品| 下体分泌物呈黄色| 又大又爽又粗| 欧美日韩精品网址| 男女下面插进去视频免费观看| 国产成人精品久久二区二区免费| 欧美日韩亚洲综合一区二区三区_| 在线观看舔阴道视频| 天天添夜夜摸| 99久久99久久久精品蜜桃| 亚洲av日韩精品久久久久久密| 日韩熟女老妇一区二区性免费视频| av在线播放精品| 欧美激情极品国产一区二区三区| 99久久99久久久精品蜜桃| 国产免费现黄频在线看| 青春草亚洲视频在线观看| a级片在线免费高清观看视频| 老司机福利观看| 国产精品香港三级国产av潘金莲| 法律面前人人平等表现在哪些方面 | 国产熟女午夜一区二区三区| 老司机靠b影院| 如日韩欧美国产精品一区二区三区| 欧美成人午夜精品| 十八禁人妻一区二区| 国产精品免费视频内射| 免费高清在线观看视频在线观看| 欧美日韩黄片免| 男人操女人黄网站| 少妇粗大呻吟视频| 热99re8久久精品国产| 亚洲国产成人一精品久久久| 在线观看免费午夜福利视频| 老熟女久久久| 各种免费的搞黄视频| 久久精品国产a三级三级三级| 人人妻人人澡人人看| 悠悠久久av| 成人黄色视频免费在线看| 999精品在线视频| 后天国语完整版免费观看| 999精品在线视频| 如日韩欧美国产精品一区二区三区| 久久久精品区二区三区| 亚洲一卡2卡3卡4卡5卡精品中文| 久久久久久久大尺度免费视频| 人人妻人人澡人人看| 99国产极品粉嫩在线观看| 操美女的视频在线观看| 在线观看一区二区三区激情| 日本猛色少妇xxxxx猛交久久| 国产主播在线观看一区二区| www.熟女人妻精品国产| 91麻豆精品激情在线观看国产 | 国产日韩欧美在线精品| 法律面前人人平等表现在哪些方面 | 波多野结衣一区麻豆| 动漫黄色视频在线观看| 一进一出抽搐动态| 91成人精品电影| 一本色道久久久久久精品综合| 亚洲精品一区蜜桃| 中文字幕色久视频| 亚洲国产看品久久| 高清在线国产一区| 精品少妇黑人巨大在线播放| 少妇猛男粗大的猛烈进出视频| 性高湖久久久久久久久免费观看| 欧美乱码精品一区二区三区| 在线看a的网站| 9热在线视频观看99| a级毛片在线看网站| 亚洲精品一卡2卡三卡4卡5卡 | 亚洲成人手机| 精品国产乱码久久久久久男人| 我要看黄色一级片免费的| 免费女性裸体啪啪无遮挡网站| 9热在线视频观看99| 亚洲五月婷婷丁香| 黄网站色视频无遮挡免费观看| 免费人妻精品一区二区三区视频| 少妇 在线观看| 欧美日韩成人在线一区二区| 欧美日韩亚洲高清精品| 波多野结衣一区麻豆| 国产一级毛片在线| av福利片在线| 欧美精品高潮呻吟av久久| 免费久久久久久久精品成人欧美视频| 日本精品一区二区三区蜜桃| 精品卡一卡二卡四卡免费| 天堂中文最新版在线下载| 狂野欧美激情性bbbbbb| 美女主播在线视频| tube8黄色片| 一级毛片电影观看| 在线天堂中文资源库| 天天躁日日躁夜夜躁夜夜| 永久免费av网站大全| 久久国产精品影院| 后天国语完整版免费观看| 亚洲精品一区蜜桃| 欧美国产精品一级二级三级| 国产一区二区三区综合在线观看| 亚洲专区字幕在线| 黄色视频,在线免费观看| 下体分泌物呈黄色| 波多野结衣一区麻豆| 亚洲国产成人一精品久久久| 中文字幕色久视频| 久久av网站| 亚洲国产欧美网| 永久免费av网站大全| 动漫黄色视频在线观看| 国产成人免费观看mmmm| 久久久欧美国产精品| xxxhd国产人妻xxx| 男女之事视频高清在线观看| 丰满饥渴人妻一区二区三| 精品国产一区二区久久| 巨乳人妻的诱惑在线观看| 亚洲av电影在线观看一区二区三区| 欧美日韩中文字幕国产精品一区二区三区 | 亚洲免费av在线视频| 两个人免费观看高清视频| 50天的宝宝边吃奶边哭怎么回事| 人人妻人人澡人人爽人人夜夜| 亚洲一区中文字幕在线| 免费观看a级毛片全部| 免费黄频网站在线观看国产| 正在播放国产对白刺激| 精品久久久久久久毛片微露脸 | 国产精品自产拍在线观看55亚洲 | 一区二区三区乱码不卡18| 亚洲激情五月婷婷啪啪| 韩国精品一区二区三区| √禁漫天堂资源中文www| 亚洲精品美女久久av网站| 一本久久精品| 在线观看免费日韩欧美大片| 精品福利观看| 女警被强在线播放| 国产主播在线观看一区二区| 国产99久久九九免费精品| 亚洲欧美精品自产自拍| 国产精品一二三区在线看| 99热网站在线观看| 18禁国产床啪视频网站| 天天躁日日躁夜夜躁夜夜| 这个男人来自地球电影免费观看| 国产在线一区二区三区精| √禁漫天堂资源中文www| 黄色视频不卡| 老司机影院成人| 波多野结衣一区麻豆| 在线观看一区二区三区激情| 精品国产乱子伦一区二区三区 | 国产精品一二三区在线看| 色婷婷av一区二区三区视频| 日韩 欧美 亚洲 中文字幕| 美女扒开内裤让男人捅视频| 另类亚洲欧美激情| 美女福利国产在线| 国产精品久久久久久人妻精品电影 | 国产精品 欧美亚洲| 亚洲国产日韩一区二区| 老司机亚洲免费影院| 国产欧美日韩一区二区精品| 日韩 欧美 亚洲 中文字幕| av国产精品久久久久影院| 肉色欧美久久久久久久蜜桃| 啦啦啦啦在线视频资源| 精品久久蜜臀av无| 日韩,欧美,国产一区二区三区| 色婷婷久久久亚洲欧美| 成人黄色视频免费在线看| 欧美在线黄色| 久久青草综合色| 男女下面插进去视频免费观看| 亚洲国产成人一精品久久久| 夫妻午夜视频| 亚洲av日韩精品久久久久久密| 九色亚洲精品在线播放| 菩萨蛮人人尽说江南好唐韦庄| 国产不卡av网站在线观看| 天天躁日日躁夜夜躁夜夜| 久久精品亚洲av国产电影网| 国产精品久久久av美女十八| 50天的宝宝边吃奶边哭怎么回事| 在线看a的网站| 国产欧美日韩一区二区三区在线| 亚洲欧洲日产国产| 色94色欧美一区二区| 欧美人与性动交α欧美软件| 欧美成狂野欧美在线观看| tube8黄色片| 看免费av毛片| 国产福利在线免费观看视频| 欧美 日韩 精品 国产| 老司机福利观看| 性高湖久久久久久久久免费观看| 亚洲五月色婷婷综合| 日韩大片免费观看网站| 老汉色av国产亚洲站长工具| 久久久久网色| 国产精品秋霞免费鲁丝片| 在线永久观看黄色视频| 午夜福利影视在线免费观看| 老熟女久久久| 成人18禁高潮啪啪吃奶动态图| 俄罗斯特黄特色一大片| 黄网站色视频无遮挡免费观看| 日韩中文字幕视频在线看片| 国产在线免费精品| 亚洲欧美日韩另类电影网站| 18禁裸乳无遮挡动漫免费视频| 日本黄色日本黄色录像| 国产精品1区2区在线观看. | 久久人妻熟女aⅴ| 国产精品久久久久久精品古装| 熟女少妇亚洲综合色aaa.| 女人久久www免费人成看片| 久久国产精品影院| 一本色道久久久久久精品综合| 国产一区二区三区综合在线观看| 国产精品久久久久成人av| 一区在线观看完整版| 久热这里只有精品99| 女人爽到高潮嗷嗷叫在线视频| 男人操女人黄网站| 在线观看人妻少妇| 啦啦啦在线免费观看视频4| 免费看十八禁软件| 国产成人系列免费观看| 国产99久久九九免费精品| 麻豆av在线久日| av在线老鸭窝| 黄片播放在线免费| 亚洲七黄色美女视频| 狠狠精品人妻久久久久久综合| 老司机午夜福利在线观看视频 | 欧美激情高清一区二区三区| 国产高清视频在线播放一区 | 日韩欧美一区二区三区在线观看 | 永久免费av网站大全| 亚洲精品一区蜜桃| 夫妻午夜视频| 肉色欧美久久久久久久蜜桃| 亚洲专区中文字幕在线| 伦理电影免费视频|