Multi-shelled CeO2 hollow microspheres as superior photocatalysts for water oxidation

Abstract

A general self-templating method is introduced to construct triple-shelled CeO2 hollow microspheres, which are composed of tiny CeO2 nanoparticles. When the triple-shelled CeO2 hollow microspheres are used as photocatalysts for direct water oxidation with AgNO3 as the electron scavenger, excellent activity and enhanced stability for O2 evolution are achieved, in contrast with commercial CeO2 nanoparticles, single-shelled CeO2 hollow microspheres and double-shelled CeO2 hollow microspheres. Such an outstanding performance is attributed to the unique properties of the triple-shelled CeO2 hollow microspheres including more efficient multiple reflections of the incident light by the inner shells, the larger surface area and more active sites for improving separation of electron–hole pairs, and the more curved surfaces unfavorable for deposition of in situ generated Ag nanoparticles.