• <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 ?

    Cu含量對Pd-Cu/鋁土礦CO氧化催化劑結(jié)構(gòu)和性能的影響

    2016-12-05 11:49:30詹瑛瑛徐聰波陳崇啟馬永德江莉龍
    無機化學(xué)學(xué)報 2016年10期
    關(guān)鍵詞:分散度雙金屬鋁土礦

    詹瑛瑛 徐聰波 陳崇啟 劉 弦 馬永德 江莉龍

    (福州大學(xué)化肥催化劑國家工程研究中心,福州350002)

    Cu含量對Pd-Cu/鋁土礦CO氧化催化劑結(jié)構(gòu)和性能的影響

    詹瑛瑛 徐聰波 陳崇啟 劉 弦 馬永德 江莉龍*

    (福州大學(xué)化肥催化劑國家工程研究中心,福州350002)

    利用資源豐富的天然鋁土礦經(jīng)NaOH溶液水熱處理后焙燒,獲得比表面積達174m2·g-1鋁土礦載體,制備了雙金屬Pd-Cu為活性組分的催化劑,金屬Pd負載量為0.5%(質(zhì)量百分數(shù)),以CO氧化反應(yīng)為探針反應(yīng),詳細考察了Cu含量的變化對催化劑物化性能的影響。研究發(fā)現(xiàn),Cu的引入有利于提高金屬Pd的分散度,同時隨著Cu含量的變化,金屬Pd與Cu之間以及金屬與鋁土礦載體之間的相互作用隨之改變。催化劑的CO氧化反應(yīng)性能評價結(jié)果表明,Pd和Cu負載量分別為0.5%和4%的樣品(PdCu4/MB)催化反應(yīng)性能最佳。結(jié)合表征結(jié)果認為,PdCu4/MB的高活性歸因于良好的Pd和Cu分散度,金屬Pd、Cu以及金屬與載體之間較強的相互作用。此外,CO-TPD表征結(jié)果說明較強的CO吸附能力和從載體中獲取氧的能力也有利于提高PdCu4/MB樣品的CO氧化反應(yīng)性能。

    鈀-銅雙金屬;堿溶液處理鋁土礦;一氧化碳氧化;銅含量

    0 Introduction

    CO oxidation(CO-Ox)is considered as one of the most direct and cheap methods to achieve CO tolerance in various applications,i.e.hydrogen purification for polymer electrolyte membrane fuel cells(PEMFCs)[1],CO gas sensor[2-3],and CO removal in automotive application[4-5]etc.An ideal catalyst for CO-Ox should be cost effective and exhibit high activity,selectivity and thermal stability.

    The noble metals(Pt[6-7],Pd[8-9],Au[10-11],etc.)and non-noble metal catalysts,such as Cu[12-13],Mn[14], Co[15-16],etc.,have been extensively studied for CO-Ox applications.In addition,noble metal and non-noble metal bimetallic catalysts were also developed due to their synergistic activity[17-19].A series of Au-based bimetallic catalysts were studied by Wang et al.[17],it was found that Au-M bimetallic catalysts showed greater tunability in structure and chemical composition than the single-metal analogues,thus providing more possibilities for improvement in activity,selectivity,and/or stability.Liu et al.[19]also reported that SBA-15-supported Au-Cu showed much better performance than monometallic(Au-or Cu-) particleswith the rich present of H2.Pd-M(M=Pt,Cu, Ni,etc.)bimetallic catalysts were also extensively investigated[20-23].A series of bimetallic Pd-Cu catalysts were synthesized from different copper precursors by Wang et al.[23],and distinguished dispersion of Cu was obtained.The Pd and Cu existed in alloy state can be reduced easily,thus showing excellent performance in CO-Ox.

    The chemically synthesized metal oxides,such as CeO2[9,24],Al2O3[22],TiO2[10]etc,were selected as supports for CO-Ox catalysts.The natural abounded and costeffective mineral,such as bauxite,diatomite or rectorite,is rarely explored for catalyst support. Natural rectoritemineralwas used as raw material for synthesis ZSM-5 by Bao et al.,and it was found that hierarchical pore structure and enhanced catalytic performance can be obtained[25].Natural bauxite, composed of Al2O3,FeOx,TiO2,CaO,SiO2[26],is found to be an excellent support for the NOxreduction in our previous work[26-28].Yet,it has not been investigated as support for CO-Ox.Herein the natural bauxite was firstly treated by hydrothermal method without any additive,following by impregnated with active metal. It is well known that NaOH can react with the Al2O3, TiO2and SiO2,hence the composition and texture(i.e. pore volume,pore diameter and surface area)of bauxitemay bemodulated by NaOH treatment.To the best of our know ledge,the investigation of NaOH-treated bauxite as support for catalyst is still unexplored.

    Therefore,herein a series of catalysts of Pd-Cu supported on bauxite,which is hydrothermal treated in NaOH aqueous solution,were fabricated.Their catalytic performances for CO-Ox were investigated. The chemical and physical properties of those catalysts were characterized by XRD,N2-physisorption,H2-TPR,CO-TPD and CO2-TPD techniques,and the relationship between their physicochemical properties and catalytic performances are discussed in detail.

    1 Experimental

    1.1 Catalysts preparation

    1.1.1 Materials

    Natural bauxite(technical grade)is from Zhangpu County,Fujian Provice,China;Palladium chloride(PdCl2),Copper(II)nitrate(Cu(NO3)2·3H2O) and Sodium hydroxide(NaOH)are all analytical grades and used without further purification.

    1.1.2 Synthesis

    Firstly,the natural bauxite was pre-treated with NaOH by hydrothermal method.Typically,10 g natural bauxite,which had been washed by deionized water and dried at100℃for 10 h,was dispersed in a certain amount of NaOH solution by ultrasonication. After that the suspension was transferred to a Teflonlined stainless steel autoclave of 100 mL capacity, sealed and heated at 120℃for 36 h.When the autoclave was cooled to room temperature naturally, the precipitate was centrifuged,dried at 110℃for 4 h,and calcined at 450℃for 2 h.The as-prepared support is named asmodified bauxite(MB).Secondly,

    the Pd and/or Cu was loaded on MB by incipient impregnationmethod,and the loading amount of Pd is fixed to 0.5%(weight percentage,wt.)with different amounts of Cu loading,e.g.0%,2%,4%,and 6%.In detail,5g of the MB and a certain amount of PdCl2and/or Cu(NO3)2·3H2O aqueous solution were mixed and soaked for 12 h at room temperature; subsequently,the as-obtained slurry was dried at 120℃for 4 h,following by calcination at 500℃for 3 h. The as-prepared Pd-Cu/bauxite catalyst is denoted as PdCux/MB,where the X is the weight ratio of Cu.

    For comparison,the monometallic Cu/MB catalysts were prepared by the same incipient impregnation method and calcined under air at 500℃for 3 h.The loading of Cu is 2%.

    1.2 Characterizations

    The powder X-ray diffraction(XRD)patterns of the samples were recorded by a PANalytical X Pert Pro diffractometer using Co Kαradiation(λ=0.179 nm)at 40 kV and 40 mA.To determine the textural properties of the as-prepared samples,nitrogen adsorption-desorption measurements were carried out at 77 K using a Micrometrics ASAP 2020 system after the sample was degassed at 200℃in a vacuum for 4 h.Temperature-programmed reduction of hydrogen (H2-TPR)measurement was carried out on an AutoChem 2920 instrument.The H2-TPR was performed by passing 10%H2/Ar(flowing rate=30 mL·min-1)on 50mg catalystata heating rate of 10℃·min-1.Prior to the measurement,the samples were pre-treated under He atmosphere at 250℃for 60 min,then cooled to ambient temperature purging with pure Argon gas.The hydrogen consumption was monitored using a Thermal Conductivity Detector (TCD).The temperature-programmed desorption of CO or CO2(CO-TPD or CO2-TPD)was also performed on the AutoChem 2920 instrument equipped with a mass spectrometer(Hiden,HPR 20).Firstly,50 mg of the sample was pre-treated with 10%H2-Ar(300℃for CO-TPD)or pure He(250℃for CO2-TPD)for 1 h. After cooling to the room temperature,the sample was purged with 5%CO-He(for CO-TPD)or pure CO2(for CO2-TPD)for 1 h.Subsequently,the sample was purging with He for 60 min until the baseline was stable,then heating to 900℃at a rate of 10℃·min-1with He.

    1.3 Evaluation of catalytic perform ance

    The catalytic activity of the catalyst for CO catalytic oxidation was tested in a fixed bed reactor at atmospheric pressure from 150 to 250℃at an interval of 25℃.Typically,1 mL of catalyst(20~40 mesh)was used and the space velocity was calculated to be 5 000 h-1;feed gas was 3%CO(volume percentage),3%O2and balance with He.Prior to the catalytic test,the catalyst was first reduced with 10% H2/N2at 250℃for 2 h.The inlet and outlet concentrations of CO were monitored by a gas chromatograph(Shimadzu GC-8A)equipped with a thermal conductivity detector(TCD).The activity was expressed by the conversion of CO,defined as:

    where VCOand VCOare the inlet and outlet content of CO,respectively.

    2 Results and discussion

    2.1 Characterizations

    2.1.1 Crystal structure and texture of the Pd-Cu/MB catalyst

    The XRD patterns of the as-prepared Pd-Cu/MB catalysts are shown in Fig.1.Those characteristic diffraction peaks of SiO2(JCPDSNo.77-1060,labeled with“#”)and Fe2O3(JCPDS No.84-0307,labeled with“*”)are ascribed to the MB support.According to the XRF characterization,the MB support ismainly composed of SiO2(13.0%,weight percentage),Fe2O3(19.7%)and Al2O3(57.6%,amorphous).When PdO and/or CuO are loaded,some diffraction peaks(2θ= 40.1°,50.2°and 65.2°)of PdO(JCPDSNo.88-2434, labeled with“?”)and CuO(JCPDS No.05-0661, labelled with“?”)are observed.By carefully examining those characteristic peaks of PdO and CuO, it can be found that their intensities are distinguished from each other with the variation of Cu loading.For the Pd/MB sample with no CuO,the diffraction peaks are sharp and narrow(Fig.1a);with the increase of

    CuO loading,the peak intensity becomes weaker. When 4%Cu was introduced,no characteristic peaks for PdO can be observed,suggesting that there must be interaction between PdO and CuO.It can be concluded that the introduction of CuO is favor for the dispersion of PdO on MB support and acquiring small crystal size of PdO.

    Fig.1 XRD patterns of the as-prepared Pd-Cu/MB catalysts

    The BET surface area(SBET)of the natural bauxite is 40 m2·g-1with pore volume(Vp)of 0.09 cm3·g-1and average pore diameter(Dp)of 13.7 nm.After hydrothermal treated with NaOH aqueous solution (MB),the SBETand Vpincrease to 174 m2·g-1and 0.25 cm3·g-1,respectively,and the Dpis greatly decrease to 5.3 nm.It is suggested that the MB provides a possibility to serve as an ideal support for CO-Ox catalyst with good texture parameters after NaOH modification.After impregnated with Pd and/or Cu, the specific surface area of those Pd-Cu/MB catalysts decrease while their Dpincrease oppositely,suggesting that the PdO and/or CuO are loaded on the surface of MB,thus blocking the partialmicro-pore ofMB.

    Table 1 Textural parameters of Pd-Cu/MB catalystwith different Cu loading

    2.1.2 Reduction property of the Pd-Cu/MB catalyst

    As seen in Fig.2,only two reduction peaks(460 and 689℃)can be observed for the MB support, which is ascribed to the reduction of Fe2O3→Fe3O4and Fe3O4→Fe,respectively;after the introduction of Pd and/or Cu,new reduction peaks are detected in the temperature range of 50~250℃.H2-TPR analysis for 5%PdO/Fe2O3catalyst was carried out by Kast et al.[8],and the PdO was started to be reduced at around 325 K.In our case,the small peak at ca.75℃for monometallic Pd/MB sample(Fig.2)can be assigned to the reduction of PdO→Pd,as is in agreement with the diffraction peaks of PdO are clearly observed in the XRD investigation(Fig.1a). Meanwhile,the reduction process of Fe2O3is greater enhanced when small amount of Pd was added, suggesting that theremust be interaction between MB support and impregnated Pd.It was reported that the formation of Pd would induce the H-spillover from Pd to support[8,29],thus lowing the reduction temperature of Fe2O3.It should be also noted that there is a broad signal in the temperature of 100~200℃(rectangle by dash line in Fig.2),suggesting the strong interaction between PdO and MB support[8].After loading with CuO(CuO/MB),a sharp peak locates at 208℃is detected to the reduction of CuO→Cu,and the shift of Fe2O3reduction temperature to lower also occurs, owing to the H-spillover effect of Cu,which originates from the interaction between CuO and MB support.As for bimetallic PdCu2/MB sample,a broad peak

    centered at 132℃up to 276℃is detected,no separate peak for the reduction of PdO can be seen, indicating that the presence of Pd alongwith Cumakes the reduction of CuO and PdO as a single broad peak. This reveals that a Pd-Cu interaction also exists in the Pd-Cu/MB catalyst,as is in good agreement with the result of XRD characterization,and the synergistic interaction between Cu and Pd further improves the reducibility of Cu species.In order to carefully examine the effectof differentamountof CuO on the reducibility of the Pd-Cu/MB catalyst,whose H2-TPR characterizationwasalso carried out,and the resultsare shown in Fig.3.

    Fig.2 H2-TPR profiles of the MB supportand as-prepared catalysts

    Fig.3 H2-TPR profiles of the as-prepared Pd-Cu/MB catalysts

    From Fig.3,it can be seen that the lowest reduction temperature for Fe2O3→Fe3O4is found for the one loaded with monometallic Pd(Fig.3a), suggesting the interaction between Pd and MB ismore efficacious in promoting the reduction of Fe2O3than that of Cu species.With the increase of CuO loading, the reduction peaks of Fe2O3→Fe3O4and Fe3O4→Fe slightly shift to higher temperature.The differences in temperature shift could be ascribed to the blocking effect of bulk CuO.Themore the CuO is introduced, the stronger the blocking effectwill be.This view will be detailedly discussed subsequently.

    In Fig.3,those peaks locate below the 300℃are assigned to the reduction of PdO and/or CuO species. H2-TPR characterization for bimetallic CuPd/CeO2catalyst was carried out by Fox et al.[30],and an intense peak centered around 160℃with a broad envelop up to 310℃was detected;after treated with HNO3,the CuO particles(similar to the bulk CuO) was removed,and only a sharp peak centering at 130℃was found,which can be attributed to the reduction of CuO clusters that highly dispersed on the CeO2surface and interacted closely with PdO.It is noteworthy in Fig.3 that all peaks of the bimetallic Pd-Cu/MB catalyst for PdO and/or CuO reduction are asymmetric,which can be decomposed to amain peak and a shoulder.Therefore there must be more than one CuOxspecies(highly dispersed and bulk CuO)in the catalysts.

    Based on the above analysis,it can be inferred that the added 2%Cu iswell dispersed on the surface of MB with extremely small amount of bulk;when more Cu is introduced,more CuO particle(bulk) appears,which is identified by the higher reduction temperature,i.e.240 and 225℃for PdCu4/MB and PdCu6/MB,respectively.As seen in Fig.3,the areas of the reduction peaks of bulk CuO increase with the increase of CuO addition,resulting in enhancing the blocking effect between Pd(and/or Cu)and MB support.The largest amount of highly dispersed CuO

    is found for the PdCu4/MB,which is thought to be favor for the catalytic CO oxidation.

    2.1.3 Surface basicity of the Pd-Cu/MB catalyst

    CO2isextensively used asa probemolecule for the investigation ofbasic property of catalyst[31-32].Different species can be formed on basic sites with diverse strengths when CO2is chemisorbed on the surface of solid bases[33].The formation of bicarbonate species involves surface hydroxyl groups(OH-,weak basic sites),whereas unidentate and bidentate carbonates are formed on surface oxygen atoms(medium-strength basic sites).CO2adsorbed as unidentate species on lowcoordinated oxygen ions shows strong basic strength (isolated O2-ions).Asaproductof catalytic CO oxidation reaction,CO2can strongly affect catalyst performance through its adsorption properties[34].Hence,the CO2-TPD analysis was carried out for the Pd-Cu/MB catalysts,and the results are shown in Fig.4.

    Fig.4 TCD signals of CO2-TPD characterizations Pd-Cu/ MB catalysts:

    Fig.5 CO2signals of CO-TPD characterizations for MBsupport and Pd-Cu/MB catalysts

    It is evident from Fig.4 that the basic properties of the as-prepared Pd-Cu/MB catalysts are influenced by the introduction of CuO.Four types of CO2-desorption peaks are collected:a weak peak(<100℃, peakα)is detected for each sample with similar intensity;a peak(peakβ)is evidence in the medium temperature range of 150~300℃,and the peak slightly increases in intensity and shifts to lower temperature with increased Cu loading;two hightemperature peaks(>300℃),peakγ(300~500℃) and peakδ(500~900℃)appear for all four catalysts, and the peak dissolves into two peaks with the increasing addition of Cu.The peakαis assigned to the weak basic sites that is associated with the bicarbonate absorbed on surface OH groups.The peak βis ascribed to the medium-strength basic sites absorbed on the M2+-O2-pairs(M=Pd or Cu),and the increase of peak intensity might be attributed to the increase of M2+-O2-pairs with rising Cu loading.The high-temperature peaks may be unidentate species strongly absorbed on low-coordinated O2-ions,and the addition of Cu results in the formation of new basic site,thus leading to the peakδdissolved.

    2.1.4 CO-TPD characterization of the Pd-Cu/MB catalyst

    Furthermore,to obtain a highly active catalyst, enough sites for catalytic adsorption of CO and providing oxygen from support are essential. Thereafter,the CO-TPD characterization for the asprepared Pd-Cu/MB was carried out,and the results are shown in Fig.5.

    The effluents of CO-TPD analysiswere traced by amass spectrometer,only CO2(m/e=44)was detected, indicating that the absorbed CO is chemical bonded to the catalyst.The chemical bonded CO interacts with

    the surface hydroxyl groups and/or oxygen species (including surface oxygen,lattice oxygen,interfacial oxygen,etc.),and desorbed as CO2during the heating process[31,35].Three desorption peaks are collected for the supported catalysts.With the increase of Cu loading,the intensity of peakαincreases accordingly, while the intensity of peakβdecreases linearly.The increase in the amount of CO2desorbs at low temperature(peakα)reflects that the ability to extract oxygen from the support by the adsorbed CO is enhanced.The largest intensity of peakαis found for the PdCu4/MB sample.

    2.2 Catalytic activity for CO oxidation of the Pd-Cu/MB catalyst The catalytic performances of the series Pd-Cu/ MB catalysts modified with different content of CuO for CO oxidation are presented in Fig.6.The catalytic activity of CuO/MB and MB support are also present for comparison.Compared to the monometallic CuO/ MB and Pd/MB,the catalytic activity is enhanced for Cu modified bimetallic Pd-Cu/MB catalysts.It also can be seen that the amount of Cu loading strongly affects their catalytic performance.When small amount of Cu was introduced(PdCu2/MB and PdCu4/ MB),the added Cu has greatly positive effect on their catalytic performances for CO oxidation,and the optimized Cu loading is found to be 4%.However, further increase in Cu loading(PdCu6/MB)leads to lower CO conversion,which is possibly related to the blocking effect of bulk CuO on the interaction between Pd and MB support and/or excessively strong adsorption of surface carbonates on the new basic sites.

    Fig.6 Catalytic activities of the as-prepared Pd-Cu/MB catalysts

    2.3 Discussions

    In the Pd-rich bimetallic Pd-Cu catalysts,the beneficial effect of copper specie is related to the formation of an active Pd-rich Pd-Cu alloy,which is more reactive than either of the monometallic(Cu orPd)clusters[36].Whereas for the Cu-rich samples, effects of copper specie are complicated,it is highly depended on the amountof Cu loading.

    Based on the above analysis,the addition of Cu is favor for the Pd dispersion,and lowering the particle size of Pd,no evident diffraction peaks for PdO can be observed when the Cu loading is higher than 4%.The good dispersion of PdO and small size of PdO particles can also be confirmed by the CO2-TPD characterization:the medium-strength basic sites increase with the increasing of Cu loading,suggesting thatmore M2+-O2-pairs(M=Pd or Cu)were generated due to the highly dispersion of Pd.Moreover,the strong interaction between metal and support or bimetallic components plays an important role in modulating the catalytic performance of supported catalyst[6,37].In Fig.2,the reduction of Fe2O3is promoted by the addition of Pd or Cu,owing to the metal-support interaction;besides,the Pd-Cu interaction can also be evidenced by the better dispersion of Pd after Cu introduction as well as asymmetric reduction peaks for the reduction of PdO and CuO shown in Fig.3.Therefore,it is reasonable to infer that the increase of Cu loading leads to better catalytic activity of the Pd-Cu/MB for CO oxidation. Actually,as seen in Fig.5,the sequitur is only fitted for the Cu loading lower than 4%,the reason is that the negative effect of the addition of excessive Cu should be taken into account.Supported Cu catalyst is reported to be also effective in catalytic CO oxidation[24,38],those Cu nanoparticles with highly

    dispersion and strongly interacts with the support are supposed to be the active sites.As clearly seen in Fig.3,the reduction peak of highly dispersed and bulk CuO can be found for the Pd-Cu/MB,and the PdCu4/ MB shows the largest amount of highly dispersion CuO nanoparticles(peak at 202℃in Fig.3c),which is thought to be favor for the catalytic CO oxidation; meanwhile,blocking effect of CuO is validated by the shift of reduction temperature of Fe2O3.Furthermore, the largest intensity of peakα(in Fig.5)is found for the PdCu4/MB sample,suggesting that for PdCu4/MB catalyst,the CO is themost easily reacts with oxygen species generating CO2.Hence,the PdCu4/MB is reasonable to show the highest catalytic activity due to the loading ofmoderate Cu.

    3 Conclusions

    A series of bim etallic Pd-Cu/MB catalysts were successfully fabricated by impregnation method using earth-abundant bauxite materials as supports.It is demonstrated that the dispersion of Pd can be enhanced by the introduction of Cu;the interaction between metal(Pd or Cu)and MB support as well as Pd with Cu results in lowering the reduction temperature of Fe2O3in MB and supported CuO.In addition,the introduction of extremely high content of Cu leads to the formation of bulk CuO and shows blocking effect on Pd-MB interaction.The highest catalytic activity for PdCu4/MB sample is ascribed to the best dispersion of Pd and Cu,strongest interaction between metal(Pd or Cu)and support as well as Pd and Cu.

    [1]Zhang Q,Liu X,Fan W,et al.Appl.Catal.B:Environ., 2011,102(1/2):207-214

    [2]Yamaura H,Moriya K,Miura N,et al.Sens.Actuators B: Chem.,2000,65(1/2/3):39-41

    [3]NishiboriM,Shin W,Izu N,et al.Catal.Today,2013,201: 85-91

    [4]Heo I,Wiebenga M H,Gaudet JR,et al.Appl.Catal.B: Environ.,2014,160-161:365-373

    [5]Seyfi B,Baghalha M,Kazemian H.Chem.Eng.J.,2009,148 (2/3):306-311

    [6]Ivanova A S,Slavinskaya E M,Gulyaev R V,et al.Appl. Catal.B:Environ.,2010,97(1/2):57-71

    [7]Li N,Chen Q,Luo L,et al.Appl.Catal.B:Environ.,2013,1 42-143:523-532

    [8]Kast P,Friedrich M,Teschner D,et al.Appl.Catal.A:Gen., 2015,502:8-17

    [9]Slavinskaya EM,Gulyaev R V,Zadesenets A V,et al.Appl. Catal.B:Environ.,2015,166-167:91-103

    [10]Kast P,KuerováG,Behm R J.Catal.Today,2015,244: 146-160

    [11]Laguna O H,Pérez A,Centeno M A,et al.Appl.Catal. B:Environ.,2015,176-177:385-395

    [12]Li J,Han Y,Zhu Y,et al.Appl.Catal.B:Environ.,2011, 108-109:72-80

    [13]de Oliveira Jardim E,Rico-Francés S,Abdelouahab-Reddam Z,etal.Appl.Catal.A:Gen.,2015,502:129-137

    [14]Zhu J,Gao Q.Microporous Mesopor Mater.,2009,124(1/2/ 3):144-152

    [15]Yu Y,Takei T,Ohashi H,et al.J.Catal.,2009,267(2):121-128

    [16]Sun S,Gao Q,Wang H,et al.Appl.Catal.B:Environ., 2010,97(1/2):284-291

    [17]Wang A,Liu X Y,Mou C Y,et al.J.Catal.,2013,308:258-271

    [18]Nikolaev S A,Golubina E V,Krotova I N,et al.Appl. Catal.B:Environ.,2015,168-169:303-312

    [19]Liu X,Wang A,Wang X,etal.Chem.Commun.,2008,(27): 3187-3189

    [20]Rosseler O,Ulhaq-Bouillet C,Bonnefont A,et al.Appl. Catal.B:Environ.,2015,166-167:381-392

    [21]Hilli Y,Kinnunen N M,Suvanto M,et al.App l.Catal.A: Gen.,2015,497:85-95

    [22]Estifaee P,Haghighi M,Mohammadi N,et al.Ultrason. Sonochem.,2014,21(3):1155-1165

    [23]Wang F,Lu G.Int.J.Hydrogen Energy,2010,35(13):7253-7260

    [24]Barbato P S,Di Benedetto A,Landi G,et al.Chem.Eng.J., 2015,279:983-993

    [25]Yue Y,Liu H,Yuan P,etal.J.Catal.,2014,319:200-210

    [26]Wang X,Chen Z,Luo Y,etal.Sci.Rep.,2013,3:1559

    [27]Wang X,Jiang L,Wang J,et al.Appl.Catal.B:Environ., 2015,165:700-705

    [28]Wang X,Wu W,Chen Z,etal.Sci.Rep.,2015,5:9766

    [29]Xu G,Zhu Y,Ma J,et al.Stud.Surf.Sci.Catal.,1997,112: 333-338

    [30]Fox E B,Velu S,Engelhard M H,et al.J.Catal.,2008,260 (2):358-370

    [31]Lin X,Chen C,Ma J,et al.Int.J.Hydrogen Energy, 2013,38(27):11847-11852

    [32]Zhu X,Shen M,Lobban L L,et al.J.Catal.,2011,278(1): 123-132

    [33]Liu Q,Wang L,Wang C,et al.Appl.Catal.B:Environ., 2013,136-137:210-217

    [34]Di Cosimo J I,Díez V K,Xu M,et al.J.Catal.,1998,178 (2):499-510

    [35]Martínez-Arias A,Fernández-Garca M,Gálvez O,et al.J. Catal.,2000,195(1):207-216

    [36]Vinod C P,Harikumar K R,Kulkarni G U,et al.Top. Catal.,2000,11-12(1/2/3/4):293-298

    [37]Li L,Song L,Wang H,et al.Int.J.Hydrogen Energy, 2011,36(15):8839-8849

    [38]Cecilia J A,Arango-Díaz A,Rico-Pérez V,et al.Catal. Today,2015,253:115-125

    Effect of Cu Content on Structure and Catalytic Performance of Pd-Cu/Bauxite for CO Oxidation Reaction

    ZHAN Ying-Ying XU Cong-Bo CHEN Chong-Qi LIU Xian MA Yong-De JIANG Li-Long*
    (National Engineering Research Center of Chemical Fertilizer Catalyst,Fuzhou University,Fuzhou 350002,China)

    We develop a bimetallic Pd-Cu catalyst that takes the advantage of Pd-Cu bimetal as active species and earth-abundant bauxite as support.The bauxite support with high surface area was obtained by hydrothermal NaOH aqueous solution treatment,and the amount of Pd is fixed to a low concentration of 0.5%(weight percentage)by incipient-wetness impregnation method.Their catalytic activity for CO oxidation reaction has also been studied.The effect of different Cu loading content on the chemical-physical properties of the as-prepared catalysts is investigated in detail.It is found that the dispersion of Pd species is promoted by the introduction of Cu species;and both Pd-Cu interaction andmetal(Pd-Cu bimetals)-support(modified bauxite(MB)interaction are modulated by varying the Cu content.Furthermore,the catalytic activities with respect to the catalytic CO oxidation are performed,and the catalyst loaded with 0.5%Pd and 4%Cu(PdCu4/MB)shows the highest catalytic activity.It is believed that the well dispersion of Pd and Cu,the strong interactions between themetals and the support as well as between Pd and Cu are responsible for the highest catalytic activity of PdCu4/MB.Moreover,it can be concluded from the CO-TPD investigation that superior abilities in adsorption of CO and extraction of oxygen from the support are favor for high catalytic activity of PdCu4/MB catalyst in CO oxidation.

    Pd-Cu bimetallic;alkali-modified bauxite;CO oxidation;Cu loading

    O643.3;O614.121

    A

    1001-4861(2016)10-1867-09

    10.11862/CJIC.2016.248

    2016-04-17。收修改稿日期:2016-09-08。

    國家高技術(shù)研究發(fā)展計劃(No.2015AA03A402)資助項目。

    *通信聯(lián)系人。E-mail:jll@fzu.edu.cn

    猜你喜歡
    分散度雙金屬鋁土礦
    雙金屬支承圈擴散焊替代技術(shù)研究
    雙金屬復(fù)合管液壓脹形機控制系統(tǒng)
    重型機械(2020年2期)2020-07-24 08:16:08
    燃氣輪機燃燒室部件故障研究
    熱力透平(2020年2期)2020-06-22 06:27:12
    雙金屬復(fù)合管焊接方法選用
    9FA燃機燃燒監(jiān)測系統(tǒng)介紹及案例分析
    今日自動化(2018年4期)2018-05-06 00:58:28
    雙金屬復(fù)合板的拉伸回彈特性研究
    開煉機混煉膠炭黑分散度數(shù)學(xué)模型研究
    農(nóng)藥分散度對藥效的影響
    CSAMT法在隱伏鋁土礦探測中的應(yīng)用研究
    河南科技(2014年7期)2014-02-27 14:11:09
    貴州省務(wù)正道鋁土礦床礦物學(xué)特征
    日日摸夜夜添夜夜爱| 免费黄网站久久成人精品| videossex国产| 日韩av免费高清视频| 国产伦精品一区二区三区视频9| 日日撸夜夜添| 久久久久久国产a免费观看| 色视频在线一区二区三区| 卡戴珊不雅视频在线播放| 日本欧美国产在线视频| 亚洲va在线va天堂va国产| 久久久精品94久久精品| av卡一久久| 在线 av 中文字幕| 国产69精品久久久久777片| 亚洲不卡免费看| 欧美一级a爱片免费观看看| 国产午夜精品一二区理论片| 成人亚洲欧美一区二区av| 成人毛片a级毛片在线播放| 亚洲真实伦在线观看| 国产精品无大码| 高清日韩中文字幕在线| 国产亚洲最大av| 国产高清有码在线观看视频| 亚洲自偷自拍三级| 欧美性感艳星| 大香蕉97超碰在线| 亚洲精品国产av蜜桃| 亚洲av成人精品一区久久| 国产成人午夜福利电影在线观看| 免费观看av网站的网址| 日韩中字成人| 中国三级夫妇交换| 偷拍熟女少妇极品色| 嫩草影院入口| 三级国产精品片| 国产乱人偷精品视频| 免费人成在线观看视频色| 尾随美女入室| 国产午夜福利久久久久久| 国产黄色免费在线视频| 亚洲一级一片aⅴ在线观看| 久久ye,这里只有精品| 久久韩国三级中文字幕| 人妻少妇偷人精品九色| 亚洲精品一区蜜桃| 国产精品人妻久久久久久| 成年版毛片免费区| 人妻夜夜爽99麻豆av| 亚洲天堂av无毛| 亚洲一级一片aⅴ在线观看| 99九九线精品视频在线观看视频| 亚洲国产最新在线播放| 国产v大片淫在线免费观看| eeuss影院久久| 99久久精品热视频| 国产精品爽爽va在线观看网站| 免费观看性生交大片5| 美女cb高潮喷水在线观看| 美女视频免费永久观看网站| 九色成人免费人妻av| 高清日韩中文字幕在线| 日韩免费高清中文字幕av| 高清在线视频一区二区三区| 亚洲欧美一区二区三区黑人 | 人体艺术视频欧美日本| 大码成人一级视频| 久久久色成人| 久久精品熟女亚洲av麻豆精品| 亚洲国产高清在线一区二区三| 99久久精品热视频| 好男人在线观看高清免费视频| 又黄又爽又刺激的免费视频.| 全区人妻精品视频| 大片电影免费在线观看免费| 国产乱来视频区| 91精品一卡2卡3卡4卡| 亚洲av国产av综合av卡| 日日摸夜夜添夜夜爱| 内地一区二区视频在线| 国产老妇女一区| 99热网站在线观看| 大香蕉97超碰在线| 久久久欧美国产精品| 亚洲一区二区三区欧美精品 | 少妇高潮的动态图| 国产精品国产三级专区第一集| 天天躁夜夜躁狠狠久久av| 成年av动漫网址| 成年av动漫网址| 欧美97在线视频| 国产成人freesex在线| 亚洲精品视频女| 97超视频在线观看视频| 国产亚洲最大av| 亚洲国产精品成人久久小说| 男人狂女人下面高潮的视频| 熟妇人妻不卡中文字幕| 中文字幕免费在线视频6| 尤物成人国产欧美一区二区三区| 国产精品蜜桃在线观看| 亚洲天堂国产精品一区在线| 小蜜桃在线观看免费完整版高清| 国产伦在线观看视频一区| 亚洲成人av在线免费| 日韩一本色道免费dvd| 免费播放大片免费观看视频在线观看| 在线观看三级黄色| 日韩强制内射视频| 王馨瑶露胸无遮挡在线观看| 熟女人妻精品中文字幕| 国产久久久一区二区三区| 欧美潮喷喷水| 国产真实伦视频高清在线观看| 校园人妻丝袜中文字幕| 中文在线观看免费www的网站| 制服丝袜香蕉在线| 欧美性猛交╳xxx乱大交人| 女人被狂操c到高潮| 岛国毛片在线播放| 日日撸夜夜添| 99热全是精品| 久久女婷五月综合色啪小说 | 亚洲va在线va天堂va国产| 天堂网av新在线| 国产爱豆传媒在线观看| 亚洲精品久久午夜乱码| 最近最新中文字幕大全电影3| 亚洲av欧美aⅴ国产| 国产精品爽爽va在线观看网站| 免费看日本二区| 成人免费观看视频高清| 亚洲精品色激情综合| 亚洲人与动物交配视频| 大香蕉久久网| 欧美精品国产亚洲| 又爽又黄无遮挡网站| 黄色日韩在线| 亚洲最大成人av| 亚洲精品456在线播放app| 国产精品一区二区在线观看99| 国产欧美另类精品又又久久亚洲欧美| 青春草国产在线视频| 久久鲁丝午夜福利片| 日日撸夜夜添| 美女高潮的动态| 黄色日韩在线| 久久ye,这里只有精品| 女的被弄到高潮叫床怎么办| 日本黄大片高清| 亚洲欧洲日产国产| 久久精品国产a三级三级三级| av.在线天堂| 欧美少妇被猛烈插入视频| 啦啦啦啦在线视频资源| 全区人妻精品视频| 日韩强制内射视频| 在线观看人妻少妇| 久久99精品国语久久久| 久久久久久久久久成人| 七月丁香在线播放| 国产人妻一区二区三区在| 中文资源天堂在线| 99久久中文字幕三级久久日本| 男插女下体视频免费在线播放| 欧美潮喷喷水| 精品久久久久久电影网| 麻豆精品久久久久久蜜桃| 亚洲最大成人中文| 免费电影在线观看免费观看| 亚洲欧美清纯卡通| 亚洲图色成人| 在线精品无人区一区二区三 | 五月伊人婷婷丁香| 在线观看美女被高潮喷水网站| 又爽又黄无遮挡网站| 看十八女毛片水多多多| 久久久成人免费电影| 男插女下体视频免费在线播放| 国产91av在线免费观看| www.av在线官网国产| 国产精品国产三级专区第一集| 久久久精品94久久精品| 国产精品熟女久久久久浪| 中文字幕免费在线视频6| a级一级毛片免费在线观看| 九草在线视频观看| 亚洲一区二区三区欧美精品 | 日本一本二区三区精品| 女人久久www免费人成看片| 男人舔奶头视频| 亚洲国产欧美在线一区| 最近中文字幕高清免费大全6| 久久久精品欧美日韩精品| 好男人在线观看高清免费视频| 国产中年淑女户外野战色| 亚洲天堂国产精品一区在线| 日本色播在线视频| 乱系列少妇在线播放| 欧美激情国产日韩精品一区| 男女边吃奶边做爰视频| 极品少妇高潮喷水抽搐| 精华霜和精华液先用哪个| 一本一本综合久久| 欧美激情久久久久久爽电影| 男女国产视频网站| 国产色爽女视频免费观看| 汤姆久久久久久久影院中文字幕| 国模一区二区三区四区视频| 18+在线观看网站| 亚洲欧美成人综合另类久久久| 乱系列少妇在线播放| 女人久久www免费人成看片| 精品久久久久久久久av| 国产综合懂色| 日韩中字成人| 国产亚洲一区二区精品| 在线观看av片永久免费下载| av在线播放精品| 国产日韩欧美亚洲二区| 久久99蜜桃精品久久| 精品久久久精品久久久| 天天一区二区日本电影三级| 中文精品一卡2卡3卡4更新| 干丝袜人妻中文字幕| 夜夜看夜夜爽夜夜摸| 欧美日韩视频高清一区二区三区二| 老师上课跳d突然被开到最大视频| 寂寞人妻少妇视频99o| 视频中文字幕在线观看| 亚洲av成人精品一区久久| 日本色播在线视频| 精品人妻熟女av久视频| av福利片在线观看| 一级二级三级毛片免费看| 国产高清三级在线| 久久99热这里只有精品18| 少妇 在线观看| 黄色日韩在线| 亚洲欧美日韩卡通动漫| 少妇的逼水好多| 久久99热这里只有精品18| 人妻系列 视频| 国产熟女欧美一区二区| 丝袜美腿在线中文| 人妻一区二区av| 国产成人精品婷婷| 别揉我奶头 嗯啊视频| 蜜臀久久99精品久久宅男| 一区二区三区乱码不卡18| 久久久久久久久久成人| 久久ye,这里只有精品| 极品少妇高潮喷水抽搐| 亚洲欧洲国产日韩| 久久久久性生活片| 中文天堂在线官网| 久久久色成人| 亚洲国产高清在线一区二区三| 国产黄片视频在线免费观看| 免费看不卡的av| 七月丁香在线播放| 晚上一个人看的免费电影| 交换朋友夫妻互换小说| 一个人观看的视频www高清免费观看| 精品视频人人做人人爽| 最近最新中文字幕免费大全7| 色视频www国产| 大话2 男鬼变身卡| 美女cb高潮喷水在线观看| 国产探花极品一区二区| 欧美一区二区亚洲| 欧美日本视频| 国产黄a三级三级三级人| 日本三级黄在线观看| 街头女战士在线观看网站| 亚洲精品国产av成人精品| 亚洲在久久综合| 国产黄a三级三级三级人| 成人亚洲精品av一区二区| 欧美精品一区二区大全| 高清欧美精品videossex| 亚洲最大成人中文| 亚洲av福利一区| 99热全是精品| 人体艺术视频欧美日本| 精品一区在线观看国产| 久热久热在线精品观看| av天堂中文字幕网| 少妇的逼好多水| 久久99热6这里只有精品| 麻豆成人av视频| 国产一区二区亚洲精品在线观看| 国产免费又黄又爽又色| 丰满人妻一区二区三区视频av| 中文字幕制服av| 婷婷色麻豆天堂久久| 亚洲四区av| 网址你懂的国产日韩在线| 天美传媒精品一区二区| 日日摸夜夜添夜夜添av毛片| 欧美另类一区| 波多野结衣巨乳人妻| 亚洲av福利一区| 国产日韩欧美亚洲二区| 七月丁香在线播放| 老师上课跳d突然被开到最大视频| 亚洲成人中文字幕在线播放| 免费看av在线观看网站| 亚洲精品,欧美精品| 亚洲人与动物交配视频| 中文字幕av成人在线电影| 一级毛片我不卡| 黄色配什么色好看| 免费观看无遮挡的男女| 国产成人精品福利久久| 建设人人有责人人尽责人人享有的 | 欧美成人午夜免费资源| 少妇人妻 视频| 亚洲精品中文字幕在线视频 | 欧美老熟妇乱子伦牲交| 亚洲国产欧美人成| 大又大粗又爽又黄少妇毛片口| 亚洲综合色惰| 亚洲不卡免费看| 国产一区二区在线观看日韩| 亚洲精品国产av蜜桃| 少妇人妻一区二区三区视频| 久久精品夜色国产| 婷婷色麻豆天堂久久| 下体分泌物呈黄色| 永久免费av网站大全| 18禁裸乳无遮挡免费网站照片| 亚洲成色77777| 国产黄片视频在线免费观看| 一个人看视频在线观看www免费| 嫩草影院精品99| 亚洲丝袜综合中文字幕| 欧美少妇被猛烈插入视频| 午夜精品一区二区三区免费看| 中国三级夫妇交换| 亚洲av成人精品一区久久| av免费在线看不卡| videos熟女内射| 亚洲伊人久久精品综合| 欧美成人午夜免费资源| 免费观看a级毛片全部| 亚洲欧美清纯卡通| 国产高清不卡午夜福利| 18禁在线播放成人免费| 国产精品99久久99久久久不卡 | 美女主播在线视频| 国产亚洲精品久久久com| 熟女av电影| 国产精品av视频在线免费观看| 插阴视频在线观看视频| www.av在线官网国产| 啦啦啦中文免费视频观看日本| 伦精品一区二区三区| 久久人人爽av亚洲精品天堂 | 中文欧美无线码| 一级黄片播放器| 国产乱人视频| 国产视频内射| 亚洲自拍偷在线| 啦啦啦啦在线视频资源| 婷婷色综合大香蕉| 日本三级黄在线观看| 九九久久精品国产亚洲av麻豆| 亚洲精品456在线播放app| 亚洲熟女精品中文字幕| 特大巨黑吊av在线直播| 日韩精品有码人妻一区| 中文字幕人妻熟人妻熟丝袜美| 日韩制服骚丝袜av| 精品人妻一区二区三区麻豆| av又黄又爽大尺度在线免费看| 免费少妇av软件| 777米奇影视久久| 亚洲人成网站高清观看| 日本猛色少妇xxxxx猛交久久| 久久精品熟女亚洲av麻豆精品| 少妇的逼好多水| 久久这里有精品视频免费| 国产一区二区亚洲精品在线观看| 欧美日本视频| 免费观看性生交大片5| 久久久久国产网址| 男男h啪啪无遮挡| 国产男女超爽视频在线观看| 2021少妇久久久久久久久久久| 欧美日韩一区二区视频在线观看视频在线 | 18禁动态无遮挡网站| 国产一区二区在线观看日韩| 日日啪夜夜爽| 免费不卡的大黄色大毛片视频在线观看| 99热这里只有是精品50| 久久精品综合一区二区三区| 亚洲av中文字字幕乱码综合| 久久综合国产亚洲精品| 伦理电影大哥的女人| 少妇猛男粗大的猛烈进出视频 | 日韩 亚洲 欧美在线| 午夜福利高清视频| 一级黄片播放器| 街头女战士在线观看网站| 亚洲精品456在线播放app| 国产一区二区在线观看日韩| av黄色大香蕉| 大码成人一级视频| 免费看不卡的av| 免费大片18禁| 大香蕉久久网| 美女cb高潮喷水在线观看| 在线看a的网站| 在线免费十八禁| 婷婷色麻豆天堂久久| 欧美3d第一页| 日韩制服骚丝袜av| 精品一区二区三卡| 国产精品精品国产色婷婷| 久久精品国产亚洲av涩爱| 国产成人免费无遮挡视频| 网址你懂的国产日韩在线| 插阴视频在线观看视频| 22中文网久久字幕| 韩国高清视频一区二区三区| 3wmmmm亚洲av在线观看| 老女人水多毛片| 少妇的逼好多水| kizo精华| 91久久精品国产一区二区成人| 久久久久久久久久人人人人人人| 插阴视频在线观看视频| 成人毛片60女人毛片免费| 日韩 亚洲 欧美在线| 久久99蜜桃精品久久| 午夜精品国产一区二区电影 | 欧美成人精品欧美一级黄| 在线观看一区二区三区| videos熟女内射| 一边亲一边摸免费视频| 波多野结衣巨乳人妻| 超碰av人人做人人爽久久| 99久久九九国产精品国产免费| 能在线免费看毛片的网站| 我的老师免费观看完整版| 最近2019中文字幕mv第一页| 亚洲精品aⅴ在线观看| 国产乱来视频区| 看非洲黑人一级黄片| 久久久久久久久久久丰满| 七月丁香在线播放| 在线观看一区二区三区激情| 日本猛色少妇xxxxx猛交久久| 熟女av电影| 亚洲国产精品成人综合色| 高清午夜精品一区二区三区| 乱系列少妇在线播放| 亚洲精品,欧美精品| 成年免费大片在线观看| 3wmmmm亚洲av在线观看| 国产大屁股一区二区在线视频| 国产成人精品婷婷| 久久亚洲国产成人精品v| 一二三四中文在线观看免费高清| 大陆偷拍与自拍| 老司机影院成人| 婷婷色麻豆天堂久久| 中文字幕制服av| 丰满人妻一区二区三区视频av| 成人综合一区亚洲| 久久久精品94久久精品| 国产成人精品福利久久| 色婷婷久久久亚洲欧美| 免费看a级黄色片| 一级av片app| 亚洲怡红院男人天堂| 国产成人精品一,二区| 一级毛片电影观看| 五月开心婷婷网| 美女cb高潮喷水在线观看| 亚洲av中文av极速乱| 香蕉精品网在线| 国产精品av视频在线免费观看| 成人综合一区亚洲| 精品少妇久久久久久888优播| 精品国产一区二区三区久久久樱花 | 免费观看无遮挡的男女| 身体一侧抽搐| 男人狂女人下面高潮的视频| 一本—道久久a久久精品蜜桃钙片 精品乱码久久久久久99久播 | 亚洲国产精品专区欧美| 美女被艹到高潮喷水动态| 女人久久www免费人成看片| 91久久精品国产一区二区成人| 亚洲欧美精品自产自拍| a级毛色黄片| 精品久久久久久电影网| 赤兔流量卡办理| 啦啦啦中文免费视频观看日本| av.在线天堂| 久久精品国产亚洲网站| 亚洲美女视频黄频| 亚洲av中文字字幕乱码综合| 91久久精品国产一区二区成人| 国产免费一级a男人的天堂| 99热这里只有是精品在线观看| 亚洲国产av新网站| 美女被艹到高潮喷水动态| 免费观看性生交大片5| 午夜福利在线观看免费完整高清在| 青春草国产在线视频| 亚洲成人中文字幕在线播放| 夜夜爽夜夜爽视频| 最近中文字幕高清免费大全6| 你懂的网址亚洲精品在线观看| 日韩一区二区三区影片| 日日撸夜夜添| 尾随美女入室| 亚洲精品国产av成人精品| 国产亚洲5aaaaa淫片| 别揉我奶头 嗯啊视频| 久久精品综合一区二区三区| 一个人看的www免费观看视频| 国产 精品1| 哪个播放器可以免费观看大片| 国产成人精品一,二区| 综合色丁香网| 日本黄大片高清| 嘟嘟电影网在线观看| 大码成人一级视频| 亚洲最大成人中文| 国产精品久久久久久精品电影小说 | 免费av毛片视频| 国产成人午夜福利电影在线观看| 欧美xxxx黑人xx丫x性爽| 久久久亚洲精品成人影院| 成人亚洲精品av一区二区| 国产男女内射视频| 亚洲色图av天堂| 国产黄色视频一区二区在线观看| 草草在线视频免费看| 秋霞伦理黄片| 91久久精品国产一区二区成人| 久久久久久九九精品二区国产| 亚洲人成网站在线播| 亚洲内射少妇av| 白带黄色成豆腐渣| 午夜激情福利司机影院| 国产成人免费观看mmmm| 国产精品不卡视频一区二区| 男插女下体视频免费在线播放| 欧美日韩在线观看h| av在线老鸭窝| 国产高清有码在线观看视频| 午夜福利高清视频| 亚洲国产精品国产精品| 狂野欧美激情性xxxx在线观看| .国产精品久久| 麻豆精品久久久久久蜜桃| 一本—道久久a久久精品蜜桃钙片 精品乱码久久久久久99久播 | 亚洲自偷自拍三级| 亚洲在久久综合| av女优亚洲男人天堂| 日韩精品有码人妻一区| 欧美高清成人免费视频www| 成人无遮挡网站| 国产午夜精品久久久久久一区二区三区| 在线观看一区二区三区激情| 亚洲欧美日韩卡通动漫| 亚洲激情五月婷婷啪啪| 伊人久久国产一区二区| 青青草视频在线视频观看| 免费观看av网站的网址| 特大巨黑吊av在线直播| 欧美少妇被猛烈插入视频| 精品国产露脸久久av麻豆| 久久99热6这里只有精品| 在线观看三级黄色| 人妻制服诱惑在线中文字幕| 最近2019中文字幕mv第一页| 高清日韩中文字幕在线| 国产探花极品一区二区| 熟女人妻精品中文字幕| 七月丁香在线播放| 国产一区二区三区综合在线观看 | 人人妻人人看人人澡| 亚洲综合精品二区| 国产精品无大码| 成人欧美大片| 午夜老司机福利剧场| 哪个播放器可以免费观看大片| 人妻 亚洲 视频| 日韩免费高清中文字幕av| 亚洲精品成人久久久久久| 波多野结衣巨乳人妻| 最近手机中文字幕大全| 3wmmmm亚洲av在线观看| 人人妻人人看人人澡| 亚洲四区av| 搡女人真爽免费视频火全软件| kizo精华| 五月天丁香电影| 久久99热这里只有精品18| 欧美激情国产日韩精品一区| 亚洲成人久久爱视频| 国产精品国产三级国产av玫瑰| 免费大片黄手机在线观看| 韩国av在线不卡| 国产成人精品婷婷| 亚洲成人av在线免费| 欧美 日韩 精品 国产| 久久ye,这里只有精品| 身体一侧抽搐|