Different titanium oxide nanoparticles were formed through pulsed discharge of Ti wires in distilled water and H2O2 solution. The recovered samples were characterized by various techniques, such as XRD, SEM and TEM. The results confirm the presence of various titanium oxide nanoparticles including TiO2 phases (anatase and rutile) and various nonstoichiometric TiO2-x in recovered samples owing to the oxygen deficient circumstance through pulsed discharge. The titanium oxide nanoparticles exhibit a spherical shape with a size of 10-300 nm. The results show that the energy input adjusted by charging voltage is one major factor to control the phases of titanium oxide and the overall oxygen content of recovered samples. In addition, the H2O2 content in distilled water also affects the oxygen content of recovered samples. The sample recovered from 10% H2O2 solution is pure TiO2 consisting of anatase and rutile without nonstoichiometric TiO2-x. Moreover, the UV-Vis absorption spectra of recovered samples show their intensive visible light absorption and the correlation between the visible light absorption and the experimental conditions (charging voltage and H2O2 content). (C) 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.