NiMoO₄/Reduced Graphene Oxide Nanocomposites\nfor Thermoelectric Power Generation

Abstract

Nickel molybdate (NMO) and its composite with reduced\ngraphene\noxide (NMO/rGO) were synthesized using an efficient solvothermal process,\nyielding NMO nanorods, and they were distributed on rGO sheets. The\nnanorods were successfully embedded within the rGO matrix. The composition\nof the elements in the synthesized compounds reveals the formation\nof NMO and NMO/rGO. NMO shows an n-type semiconducting property, and\nit shows an increment in electrical conductivity and the Seebeck coefficient\nbetween 483 and 573 K. The incorporation of rGO significantly enhanced\ncarrier mobility facilitated by the low-energy barriers between the\ngrains. NMO/rGO shows p-type transport properties, with an increment\nin the Seebeck coefficient due to the energy filtering effect. The\ncomposite exhibited a notable enhancement in the power factor, driven\nby the increased electrical conductivity and increased Seebeck coefficient\ndue to the synergistic effect. Furthermore, a reduction in thermal\nconductivity was observed, attributed to phonon scattering centers\nat the NMO/rGO interface. The thermoelectric figure of merit of the\nNMO/rGO composite was enhanced by approximately 135 times compared\nto pristine NMO, demonstrating the potential of rGO to enhance the\nthermoelectric power generation efficiency.