Designing Catalysts for Tomorrow’s Environmentally Benign Processes

Abstract

After first recalling some of the key challenges involved in meeting the demands for energy and chemicals by 2050, brief accounts are given of (a) the present scene in water oxidation photocatalysis with particular reference to TiO2 and other oxides possessing the appropriate band gap and (b) of band structure engineering of semiconductors for enhanced photoelectrochemical water splitting. The photochemical possibilities of metal–organic frameworks are then briefly outlined as are (c) some of the solids (mainly TiO2) for the destruction of pollutants and other substances that are environmentally aggressive. Solar-cavity receivers for the catalytic (thermochemical) conversion of CO2 to CO and H2O to H2 are then considered. The principal feature of this article is an analysis, with specific examples, of some existing catalysts that are likely to prove difficult to replace. Biorefineries for producing transportation fuels and bulk chemicals are then considered. The article concludes with the prospects for the design of new catalysts and, in particular, with the fertility of the concept of single-site heterogeneous catalysts in both thermal and photochemical contexts.