Sustainable hydrogen production systems are of great importance to the future of mankind, and photocatalysis represents one of the technologies currently showing promise as a method for hydrogen production. Understanding how such catalysis proceeds is important, and here we report some of our work on the anaerobic photocatalytic reforming of methanol at ambient temperatures. This utilises a metal-titania catalyst, but only a very limited range of metals are suitable, the best being Pd, Pt and Au. The reaction requires both surface titania and metal to be present, and shows a very strong dependence on the loading of the metal. A model for the reaction is presented. (c) 2007 Elsevier B.V. All rights reserved.