Environmental and clean energy concerns were responsible for another impetus on the search for new sol-gel materials. For example, recent results with doped sol-gels of long-lasting photobioreactors and biofuel cells, which can advantageously exploit solar radiation to convert polluting carbon dioxide into useful biofuels and electricity,18 constitute a significant advance toward the practical chemical exploitation of solar energy. First, there is a need for a perspective and unified view on the actual development of the science and technology behind these advanced materials, especially in light of the fast growth in scientific publications addressing disparate new applications in fields as diverse as catalysis for fine chemicals and healthcare. Second, there is a strong contemporary research interest in clean energy and environmental issues.