Experimental comparison of the effect of temperature on the vibrationaland morphological properties of NixCo3-xO4 nanostructures

Leydi Julieta Cardenas Flechas, Elena Xuriguera Martín, Jose Antonio Padilla Sanchez, Josep M. Chimenos Ribera, Miryam Rincón Joya.

https://doi.org/10.1016/j.matlet.2021.130477

This work presents the experimental comparison of the effect of temperature and nickel addition on the synthesis of Ni_xCo₃-xO₄ nanostructures x = 0.01, 0.04, 0.1, 0.16, using the sol–gel technique with final heat treatment at 600 ºC and 800 ºC. X-ray diffraction (XRD) analysis indicates the formation of pure Co₃O₄ at 600 ºC and the appearance of an additional residual NiO phase at 800 ºC.

The presence of this phase evidences a deviation in the peaks of the diffraction angle to lower ones generated by the difference in ionic radii, which is related to the insertion of larger ions (Ni²⁺) doped in the matrix of Co₃O₄. Scanning electron microscope (SEM) analysis indicates that there is a densification of the grains at higher temperatures, possibly associated with the thermal effect that generates greater interdiffusion. Fourier-transform infrared spectroscopy (FTIR) spectra show two main absorption bands with vibrations Co²⁺¬O, Co³⁺¬O and Ni¬O in 456 cm^-1. The effect of doping generates adisplacement in the bands that are evident in the Raman analysis, where the vibrational mode A1g at 600 ºC is translated 28.07 cm^-1. The values of SBET specific surface area indicate that as temperature increases, the surface area and volume of micropores decreases.

Funding

This research was funded by Fundación Carolina–SEGIB.

Research category: Metallurgy