Titanium dioxide is a well-studied and popular photocatalyst, but a number of factors still prevent its widespread use in a number of commercial applications. In this thesis we explored the synthesis of titanium dioxide nanoparticles via the sol-gel method, with the goal of creating a viable catalyst for the visible-light degradation of wastewater dyes. A number of different synthetic pathways were explored and developed, and the products categorised with respect to nanoparticle size, shape and crystallinity as well as electronic and photocatalytic properties.