Thermal study on release of lattice oxygen from carbon-bearing Ni(II) ferrite

O2-release from carbon-bearing Ni(II) ferrite (CBNF) was studied with TG-MS and DSC. Release of lattice oxygen as O2 was found to take place at 200–300°C and was associated with an endothermic temperature peak. The proposed thermochemical reaction is Olat.(s) = Vö(s) + (12) O2(g), ΔH° = 424.5 kJ/mol, where Olat.(s) and Vö(s) denote the lattice oxygen of CBNF and the oxygen-deficient site on the surface of the CBNF. At a temperature higher than 350°C, lattice oxygen was released as CO2 and was accompanied by a decrease of deposited carbon.