eng Science and Education Publishing World Journal of Chemical Education 2375-1657 2023-08-22 11 3 54 59 10.12691/wjce-11-3-6 WJCE20231136 article Edwin Bogdan 1 Christoph Weidmann 1 Thomas Waitz twaitz@gwdg.de 1 Department of Chemistry Education, Georg-August-University, G?ttingen, Germany We present a gas sensor using nanoporous titanium dioxide which is fabricated by anodic oxidation of a titanium foil. The process is easy to handle, can be carried out at low cost and the sensor response to reducing gases can be measured using a cheap digital multimeter. In contrast to the most gas sensors, no commercially available sensor substrate is required. The band model for semiconductors and a model of ionosorption provides an explanation for the working principle of the gas sensor on particle level. Several experimental approaches for upper-secondary chemistry class are presented. http://pubs.sciepub.com/wjce/11/3/6/wjce-11-3-6.pdf gas sensor titanium dioxide band model