TiO2 is the most popular and promising high-activity photocatalyst and has many applications. Recently, photocatalysis in microreactors has attracted attention due to its effective light irradiation and short diffusion distance. This article introduces our study on the fabrication of TiO2/Ti bilayer plates and their application in a photocatalytic microreactor. First, TiO2 layers with controlled nanostructures were fabricated via the direct oxidation of Ti plates. A network-like and flake-like nanostructure of TiO2 was formed on the surface of Ti plates by alkaline treatment. TiO2 nanotube arrays were formed by anodization of the Ti plate. These TiO2/Ti plates exhibited high photocatalytic performance in the microreactor, which was enhanced by developing the nanostructure. Second, we developed a new photocatalytic microreactor with stacked channels for oxidation and reduction employing the charge separation effect of the TiO2/Ti plate. The UV irradiation of the TiO2-side channel generates pairs of holes and electrons, which are separated by the TiO2/Ti plate and contribute to oxidation and reduction in the different channels. We confirmed the feasibility of this microreactor and demonstrated that the pH difference in the two channels was the important factor enhancing the reduction induced by transferred electrons. (C) 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.