Synthesis and characterization of carbon aerogels doped with the anatase form of titanium oxide

TiO₂-doped carbon aerogels (CAs) were synthesized by sol–gel polymerization of a mixture of resorcinol, formaldehyde and tetrabutyl orthotitanate, followed by gelation and supercritical drying and carbonization in N₂ gas atmosphere. The morphology of these TiO₂-doped CAs was characterized by transmission electron microscopy. X-ray diffraction and Brunauer–Emmett–Teller methods were employed to determine the microstructure and surface characteristics of samples. It was found that the doped TiO₂ had no significant effect on the surface area of the samples, whereas the pore and mesopore volumes were increased by the addition of TiO₂. The TiO₂ particles were kept still as anatase in samples carbonized at 900 °C, and did not transform into rutile on heating. Electrochemical performance of the samples as electrode materials was studied by cyclic voltammetry, electrochemical impedance spectroscopy, and constant current charge/discharge measurements. The results showed that the specific capacitance of CA electrodes had been improved by TiO₂ doping, and the samples with wider pore diameters have higher capacitance values.