Influence of hydrogenation conditions on the structural, optical, and magnetic properties of degenerated Ni/Al co-doped anatase nanocomposite

Abstract

In the present work, pristine and Ni2+/Al3+- codoped anatase (TiO2) nanocomposite powders were synthesized by the thermal co-precipitation method. The samples were characterized by several techniques. The X‐Ray diffraction (XRD) was used for structural characterization and the optical absorption spectroscopy was used for the optical characterization. The structural/optical studies proved the formation of a substitutional solid solution (SSS). The magnetization measurements were performed to investigate the magnetic properties of the synthesized samples. In the present work, nickel (Ni2+) dopant ions were used to introduce stable ferromagnetic (FM) properties into the synthesized anatase, while Al3+ dopant ions were utilized to supply itinerant electrons necessary to support and boost the created FM properties. The roadmap of the present work was to establish the hydrogenation conditions necessary to create ferromagnetic (FM) properties in the host codoped samples and study the effect of hydrogenation temperature on the parameters of the created FM properties, especially the magnetic energy (Umag) and saturation magnetization (Msat). It was found that the created FM properties in Ni/Al-doped TiO2 nanocomposite powder by using the hydrogenation effect could be enhanced and controlled via the temperature of the hydrogenation (TH). The experimental results revealed that Umag of TiO2:Ni:Al system increased by ~241% and the saturation magnetization by ~140% with increasing of TH by 100 oC (from 400 oC to 500oC). The obtained saturation magnetization (Msat) of 1.09 emu/g and magnetic energy (Umag) of 42.6 erg/g were higher than the previously obtained values for created Ni-doped TiO2 by ~50 times. Such great novel results were obtained due to dealing with two factors; the Al3+ ions as co-dopant, which can supply an excess of itinerant electrons that boost the S.S Heisenberg interactions in addition to choosing a suitable temperature of hydrogenation.