Cerium oxide is an earth-abundant,highly researched multifunctional oxide with great technological importance and wide applications area.Trivalent rare earth(RE^(3+))dopants modify the defects concentration,create ple...Cerium oxide is an earth-abundant,highly researched multifunctional oxide with great technological importance and wide applications area.Trivalent rare earth(RE^(3+))dopants modify the defects concentration,create plenty of Ce^(3+)■Ce^(4+)redox centres and generate numerous oxygen vacancies than the pure ceria.In the present work,CeO_(2)(CE),10 mol%Gd doped ceria(Ce_(0.9)Gd_(0.1)O_(2-δ);CGO),and 10 mol%Sm doped ceria(Ce_(0.9)Sm_(0.1)O_(2-δ);CSO)were synthesized by sol-gel auto-combustion method.The phase formation,particle morphology,and elemental distribution of the synthesized powder samples were studied by X-ray diffraction,Fourier transform infrared spectroscopy,field emission scanning electron microscopy,and energy dispersive X-ray analysis.UV-diffuse reflectance spectroscopy was used to study the optical properties of the material.The band gaps of the CE,CSO and CGO were calculated to be2.81,2.71 and 2.60 eV,respectively.Electrochemical impedance spectroscopy(EIS)at room temperature(RT)investigated the materials'electrical properties.The improved electrical conductivity was registered for the doped variants.CGO reaches the highest one(0.4×10^(-7)S/cm)at RT.Cyclic voltammetry(CV)was performed to study the oxidation-reduction behavior and reversibility of the ion intercalation-deintercalation process of the materials in an electrolyte solution.For the doped ceria,a threefold improved current density is observed for the cathodic part,while a small improvement is reflected in the anodic part.Specific capacitance(C_(sp))was calculated at the Faradaic and non-Faradaic region of the voltammograms.C_(sp)of the materials increases in the order of CE<<CSO<CGO.The highest Csp 345.16 F/g at a scan rate of 5 mV/s is obtained for the CGO.Lastly,a correlation is drawn by analysing cyclic voltammograms to conclude the applicability of the doped ceria material for roomtemperature water-electrolysis in the alkaline medium.展开更多
文摘Cerium oxide is an earth-abundant,highly researched multifunctional oxide with great technological importance and wide applications area.Trivalent rare earth(RE^(3+))dopants modify the defects concentration,create plenty of Ce^(3+)■Ce^(4+)redox centres and generate numerous oxygen vacancies than the pure ceria.In the present work,CeO_(2)(CE),10 mol%Gd doped ceria(Ce_(0.9)Gd_(0.1)O_(2-δ);CGO),and 10 mol%Sm doped ceria(Ce_(0.9)Sm_(0.1)O_(2-δ);CSO)were synthesized by sol-gel auto-combustion method.The phase formation,particle morphology,and elemental distribution of the synthesized powder samples were studied by X-ray diffraction,Fourier transform infrared spectroscopy,field emission scanning electron microscopy,and energy dispersive X-ray analysis.UV-diffuse reflectance spectroscopy was used to study the optical properties of the material.The band gaps of the CE,CSO and CGO were calculated to be2.81,2.71 and 2.60 eV,respectively.Electrochemical impedance spectroscopy(EIS)at room temperature(RT)investigated the materials'electrical properties.The improved electrical conductivity was registered for the doped variants.CGO reaches the highest one(0.4×10^(-7)S/cm)at RT.Cyclic voltammetry(CV)was performed to study the oxidation-reduction behavior and reversibility of the ion intercalation-deintercalation process of the materials in an electrolyte solution.For the doped ceria,a threefold improved current density is observed for the cathodic part,while a small improvement is reflected in the anodic part.Specific capacitance(C_(sp))was calculated at the Faradaic and non-Faradaic region of the voltammograms.C_(sp)of the materials increases in the order of CE<<CSO<CGO.The highest Csp 345.16 F/g at a scan rate of 5 mV/s is obtained for the CGO.Lastly,a correlation is drawn by analysing cyclic voltammograms to conclude the applicability of the doped ceria material for roomtemperature water-electrolysis in the alkaline medium.
