On the use of microwaves during combustion/calcination of N-doped TiO2 precursor: An EMW absorption study combined with TGA-DSC-FTIR results

[Display omitted] •First in-situ measure of dielectric properties and EMW absorption of N-TiO2 precursor.•Complex combustion synthesis of N-doped TiO2 precursor via simultaneous DSC/TGA/EGA.•MW calcination of N-doped TiO2 nanoparticles via hybrid heating.•MW output optimization with combination of thermal and dielectric measurements.•Accurate definition of weight loss, volume change and nature of evolved gas in CS. For the first time, dielectric properties and electromagnetic wave (EMW) absorbing performance of a precursor for N-doped TiO2 nanoparticles undergoing combustion synthesis are reported. The precursor contains titania, NH4Cl as source of N atoms for TiO2 nanoparticles doping, and organics. Thermogravimetric analysis (TGA) reveals that the 180–450 °C temperature range accounts for the overall weight loss of the process. High-temperature gas evolution analysis confirms combustion of the organic component. Aiming to optimize output power and time schedule of the material’s microwave (MW) calcination, in situ high temperature dielectric properties measurements were recorded during MW irradiation in a dedicated cavity. Results revealed that after a first stage of non-combustive decomposition, in a second stage the EMW absorption decreases, so MW power is no longer necessary and hybrid heating is suggested to reach the desired calcination temperature (375–400 °C).