Investigating Local Structure of Ion-Implanted (Ni<sup>2+</sup>) and Thermally Annealed Rock Salt CoO Film by EXAFS Simulation Using Evolutionary Algorithm
Latif Ullah Khan, Naila Jabeen, Isma Jabbar, Sadaf Jamil, Afia Kanwal, Zareen Akhter, Muhammad Usman, Muhammad Zeeshan Abid, Messaoud Harfouche
Abstract
The CoO film deposited on the surface of F-doped SnO2 (FTO) conductive glass was prepared via drop casting technique. The effects of Ni2+-ion implantation at 700 keV energy and postannealing in vacuum at 450 °C temperature on the local structure of the CoO film was systematically explored. The XAFS study revealed the substitution of octahedral Co2+ by Ni2+ ion (Co1–xNixO) as a result of ion implantation. The existence of defects in local structure around the octahedral Co for the Co1–xNixO film after thermal annealing in vacuum was demonstrated by the theoretical EXAFS [χ(k)] simulation via evolutionary algorithm implemented in reverse Monte Carlo method in rationale with EXAFS fitting. Nevertheless, the cubic rock salt structure for the Co1–xNixO was conserved, corroborated through XRD patterns, suggesting a remarkable candidate for application as an electrocatalyst in fuel cells.