Study of carbon/copper nanocomposite synthesized by sol–gel method

Organic–inorganic nanocomposite was obtained after the incorporation of cupric oxide (CuO) nanoparticles in a host matrix based on pyrogallol and formaldehyde (PF) using sol–gel method. The material was subjected to heat treatment under inert atmosphere at 650 °C during 2 h to obtained PF/Cu-650 nanocomposite. The X-ray diffraction analysis exhibited the presence of two phases: metallic copper Cu and graphite C. The voltage–current V(I) characteristics present a negative differential resistance at room temperature. The evolution of the conductivity as a function of measurement temperature indicates the dominance of the three dimensions Godet-variable range hopping transport model. The alternative current conductance was investigated using admittance spectroscopy; the obtained curves show the presence of hopping conduction mechanism. The Nyquist diagrams were used to identify an equivalent circuit and the fundamental parameters of the circuit are determined with the aim to study the contributions of the grains and grain boundaries to the conductivity.