Investigation into the Characteristics of Nanoporous Carbon/Silica-Nickel Nanocomposite for high-frequency Applications

The synthesis process involved integrating nickel oxide nanoparticles into a Carbon/Silica host matrix using the sol-gel method, resulting in the formation of a Carbon/Silica-Nickel nanocomposite. This nanocomposite was subjected to pyrolysis at 650 °C for two hours.The XRD diffractogram revealed a broad diffraction peak characteristic of amorphous silica and carbon phases, alongside three distinct peaks attributed to nickel. The XPS analysis identified five prominent peaks corresponding to Si 2p, Si 2s, C 1s, O 1s, and Ni 2p. SEM and TEM images showcased the porous texture and agglomeration of nanoparticles, respectively. FTIR spectroscopy indicated the presence of three major peaks associated with Si-O-Si, C-C, and Ni-O vibrations. Raman spectroscopy showed that electrical conduction is facilitated by the graphite nanoparticles. The direct current electrical conductivity (σ_dc) was exploited using Variable Range Hopping and Nearest Neighbor Hopping conduction models. The alternating current electrical conductivity (σ_ac) suggested the dominance of the Overlapping Large Polaron Tunnelling model. The complex impedance and electrical modulus were studied to determine the equivalent circuit and understand the electric relaxation process. The dielectric properties explained the occurrence of Maxwell-Wagner interfacial polarization.