IrO2 and IrRuOx(Ir:Ru 60:40 at%),supported by 50 wt%onto titania nanotubes(TNTs)and(3 at%Nb)Nb-doped titania nanotubes(Nb-TNTs),as electrocatalysts for the oxygen evolution reaction(OER),were synthesized and character...IrO2 and IrRuOx(Ir:Ru 60:40 at%),supported by 50 wt%onto titania nanotubes(TNTs)and(3 at%Nb)Nb-doped titania nanotubes(Nb-TNTs),as electrocatalysts for the oxygen evolution reaction(OER),were synthesized and characterized by means of structural,surface analytical and electrochemical techniques.Nb doping of titania significantly increased the surface area of the support from 145(TNTs)to 260 m2g-1(Nb-TNTs),which was significantly higher than those of the Nb-doped titania supports previously reported in the literature.The surface analytical techniques showed good dispersion of the catalysts onto the supports.The X-ray photoelectron spectroscopy analyses showed that Nb was mainly in the form of Nb(IV)species,the suitable form to behave as a donor introducing free electrons to the conduction band of titania.The redox transitions of the cyclic voltammograms,in agreement with the XPS results,were found to be reversible.Despite the supported materials presented bigger crystallite sizes than the unsupported ones,the total number of active sites of the former was also higher due to their better catalyst dispersion.Considering the outer and the total charges of the cyclic voltammograms in the range 0.1–1.4 V,stability and electrode potentials at given current densities,the preferred catalyst was Ir O2 supported on the Nb-TNTs.The electrode potentials corresponding to given current densities were between the smallest ones given in the literature despite the small oxide loading used in this work and its Nb doping,thus making the Nb-TNTs-supported IrO2 catalyst a promising candidate for the OER.The good dispersion of IrO2,high specific surface area of the Nb-doped supports,accessibility of the electroactive centers,increased stability due to Nb doping and electron donor properties of the Nb(IV)oxide species were considered the main reasons for its good performance.展开更多
采用溶剂蒸发自组装法(EISA)制备较高比表面积的钒掺杂介孔TiO2,并利用亚当斯熔融法(Adams Fusion Method),在不同掺杂程度的[Ti100-x V x]1O2(x=0,1,5)载体的表面上合成IrO2纳米颗粒。XRD与TEM实验结果显示,[Ti100-x V x]1O2载体在负载...采用溶剂蒸发自组装法(EISA)制备较高比表面积的钒掺杂介孔TiO2,并利用亚当斯熔融法(Adams Fusion Method),在不同掺杂程度的[Ti100-x V x]1O2(x=0,1,5)载体的表面上合成IrO2纳米颗粒。XRD与TEM实验结果显示,[Ti100-x V x]1O2载体在负载IrO2后发生了锐钛矿到金红石的相转变,新相晶粒有所长大,但随着V掺杂量的增多晶粒生长受到抑制。N2吸脱附测试结果表明:在负载IrO2后整体比表面积有所降低,未掺V的样品降低程度较大;在0.1mol/L HClO4溶液及N2气氛下对40wt%担载量的IrO2/[Ti100-x V x]1O2(x=0,1,5)和纯IrO2进行循环伏安测试,电流密度随V掺杂量的提高而显著提高,证明V掺杂手段可显著提高复合催化剂的导电性以及催化活性,有望通过进一步改进使V掺杂TiO2成为新型的SPE阳极载体材料。展开更多
文摘IrO2 and IrRuOx(Ir:Ru 60:40 at%),supported by 50 wt%onto titania nanotubes(TNTs)and(3 at%Nb)Nb-doped titania nanotubes(Nb-TNTs),as electrocatalysts for the oxygen evolution reaction(OER),were synthesized and characterized by means of structural,surface analytical and electrochemical techniques.Nb doping of titania significantly increased the surface area of the support from 145(TNTs)to 260 m2g-1(Nb-TNTs),which was significantly higher than those of the Nb-doped titania supports previously reported in the literature.The surface analytical techniques showed good dispersion of the catalysts onto the supports.The X-ray photoelectron spectroscopy analyses showed that Nb was mainly in the form of Nb(IV)species,the suitable form to behave as a donor introducing free electrons to the conduction band of titania.The redox transitions of the cyclic voltammograms,in agreement with the XPS results,were found to be reversible.Despite the supported materials presented bigger crystallite sizes than the unsupported ones,the total number of active sites of the former was also higher due to their better catalyst dispersion.Considering the outer and the total charges of the cyclic voltammograms in the range 0.1–1.4 V,stability and electrode potentials at given current densities,the preferred catalyst was Ir O2 supported on the Nb-TNTs.The electrode potentials corresponding to given current densities were between the smallest ones given in the literature despite the small oxide loading used in this work and its Nb doping,thus making the Nb-TNTs-supported IrO2 catalyst a promising candidate for the OER.The good dispersion of IrO2,high specific surface area of the Nb-doped supports,accessibility of the electroactive centers,increased stability due to Nb doping and electron donor properties of the Nb(IV)oxide species were considered the main reasons for its good performance.
文摘采用溶剂蒸发自组装法(EISA)制备较高比表面积的钒掺杂介孔TiO2,并利用亚当斯熔融法(Adams Fusion Method),在不同掺杂程度的[Ti100-x V x]1O2(x=0,1,5)载体的表面上合成IrO2纳米颗粒。XRD与TEM实验结果显示,[Ti100-x V x]1O2载体在负载IrO2后发生了锐钛矿到金红石的相转变,新相晶粒有所长大,但随着V掺杂量的增多晶粒生长受到抑制。N2吸脱附测试结果表明:在负载IrO2后整体比表面积有所降低,未掺V的样品降低程度较大;在0.1mol/L HClO4溶液及N2气氛下对40wt%担载量的IrO2/[Ti100-x V x]1O2(x=0,1,5)和纯IrO2进行循环伏安测试,电流密度随V掺杂量的提高而显著提高,证明V掺杂手段可显著提高复合催化剂的导电性以及催化活性,有望通过进一步改进使V掺杂TiO2成为新型的SPE阳极载体材料。
