Research on the synergistic doped effects and the catalysis properties of Cu2+ and Zn2+ co-doped CeO2 solid solutions

The Cu 2+ and Zn 2+ co-doped CeO 2 -based solid solutions were synthesized via hydrothermal method . The microstructure and the spectra features of the solid solutions were characterized systematically. The XRD results showed that the dopants were incorporated into the CeO 2 lattice to form Ce 1-x Cu 0.5x Zn 0.5x O 2 solid solutions when x was lower than 0.14. The cell parameters and the crystalline size decreased linearly, and the lattice strain gradually increased with increasing the doping level. The TEM patterns showed that the particle size in the solid solution was lower than 10 nm which is in accordance with the XRD results. The ICP analysis indicated that the real doped content in the solid solution was close to the nominal proportion. XPS proved that the Ce 3+ component was increased by doping. The Raman and PL spectra indicated that the lattice distortion and the oxygen vacancies also increased following the same trend. At the same time, the synergistic effects of two ions co-doped solid solutions were studied by comparing them with that of single ions doped samples. The catalysis effects of Cu 2+ and Zn 2+ co-doped CeO 2 -based solid solutions on the hydrogen storage electrochemical and kinetic properties of Mg 2 Ni alloys were detected. The electrochemistry properties of the Mg 2 Ni-Ni-5 wt% Ce 1-x Cu 0.5x Zn 0.5x O 2 composites indicated that the doped catalysts could provide better optimizations to improve the maximum discharge capacities and the discharge potentials. On the other hand, the charge transfer abilities on the surface and diffusion rate of H atoms in the bulk of alloys also got improved. The DSC measurements showed that the hydrogen desorption activation of the hydrogenated composites with Ce 0.88 Cu 0.06 Zn 0.06 O 2 solid solutions decreased to 77.03 kJ mol −1 , while that of the composites with pure CeO 2 was 97.62 kJ mol −1 . The catalysis effect was enhanced by the doped content increase that means that the catalysis mechanism had close links to the oxygen vacancy concentration and the lattice defects in the solid solutions. On the other hand, the doped Cu 2+ and Zn 2+ ions could also play an important role in the catalytic process.