Book excerpt: This book discusses recent advances in the photocatalytic and electrophotocatalytic applications of titanium dioxide nanocomposites containing polymers and other components. These materials possess photocatalytic, virucidal and antimicrobial efficacy and water and air cleaning abilities against eco-toxicants, and allow water splitting for the generation of chemical fuels. The book considers the ability of nanocomposites’ components to reinforce titania functionality in photocatalysis and photoelectrocatalysis, and presents an overview of their occurrence in nature, their thermodynamic properties, and their toxicity. The volume will be of interest to chemists and material science specialists and practitioners, as well as any reader interested in the recent scientific achievements for green and sustainable development.