Photocatalytic nanomaterials have a great potential in such applications as reduction of carbon dioxide and degradation of various pollutants. They are equally important in the production and storage of energy, e.g. in the conversion of solar energy to electricity, and the production of hydrogen in photoelectrochemical cells. Research on synthesis, characterization and specific applications is reported for titanium oxide and a number of other promising catalysts, such as silver phosphate, cerium oxide, zinc oxide and zinc sulfide.