10 - Pyrochlores: Prospects as a photocatalyst for environmental and energy applications

Abstract

The appropriate design of stable photoactive oxides is a key step toward harnessing energy from the solar spectrum for environmental and energy applications. Pyrochlores, a group of ternary oxides commonly having stoichiometry as A2B2O7, where A and B are cations suitable to form eight and six coordinated polyhedra with O2− ions, are being explored in recent years for a wide range of applications. The high chemical stability and low photocorrosion are the unique features of pyrochlores that have made them promising candidates for photoactive catalysts for environmental and energy applications. The compositional flexibility of pyrochlore-type materials allows easy tunability of electron/hole mobility by introducing different metal ions in the lattice. This chapter is focused on the photocatalytic application of pyrochlores, either standing alone or as part of composites in energy and environmental remediation. The chapter covers a brief introduction to photocatalysis and pyrochlore structures and compositions. The scope of the pyrochlore-type materials for tunable bandgaps is also discussed. Subsequently, several examples of photocatalytic reactions with pyrochlore-type materials are examined.