Impact of Ni Ion-Doping on Structural, Optoelectronic and Redox Properties of CeO2 Nanoparticles

We have investigated the influence of Ni doping on the physicochemical properties of CeO2 synthesized by a co-precipitation process. As-prepared nanoparticles were characterized by x-ray diffraction pattern (XRD), transmission electron microscopy (TEM), energy dispersive x-ray analysis, thermal analysis, Fourier transform infrared spectra, optical absorption and temperature program reduction techniques. The observed results clearly demonstrate the impact of Ni ion concentration on the crystallinity, optoelectronic and reducibility of CeO2 nanoparticles. XRD results show that the particle size was decreased after increasing the Ni ion-doping concentrations. TEM micrographs exhibited high aggregation in high Ni ion-doping concentration causing the smallest grain size of the materials. The band gap energies increased with decreasing particle size because of the higher oxygen-releasing capacity and stronger interaction between nickel and the CeO2 matrix. The 7% mol Ni-doped CeO2 exhibits low-temperature reduction. Because of excellent optoelectronic and redox properties, magnetically active Ni ion-doped CeO2 nanoparticles can be used for electrochemical biosensors and solid oxide fuel cell catalysts can be potentially extended to other applications.