The photocatalytic behaviour of TiO2 has been thoroughly investigated the past years using UV light to photoactivate TiO2. As this method introduces complications making it difficult to do it economically viable, new pathways to activate TiO2 have been sought. In the present work, reactive oxygen species (ROS) were obtained in a suspension of hydrogen peroxide (H2O2) and titanium dioxide (TiO2) in darkness, offering an alternative method to initiate oxidative behaviour of TiO2. Methylene blue (MB) degradation was chosen as an indicator for measuring the catalytic effect, allowing for a comparison of the reaction kinetics with other methods to create ROS with TiO2. The effects of TiO2 particle effective surface area and concentration of H2O2 were also studied. EPR studies were made to determine the presence of free radicals in the mixture of TiO2/H2O2 in darkness. Under the given lighting conditions, the results demonstrate the relevance of the TiO2 effective surface area and concentration of H2O2 and TiO2 as parameters influencing the chemical catalysis of MB due to the action of hydroxyl (OH) and/or hydroperoxide radicals (HO2). © 2013 Elsevier B.V.