Hydrothermally prepared nanosized and mesoporous Ce0.4Zr0.6O2 solid solutions with shape dependence in photocatalysis for the degradation of methylene blue

Abstract

Mesoporous Ce_0.4Zr_0.6O₂ solid solutions with four different shapes, including mixed nanorod and nanoparticle (RP, cubic), nanopolyhedron (PH, tetragonal), nanosphere (SP, cubic) and nanoegg (EG, tetragonal), were hydrothermally fabricated. Various physical and chemical techniques were used to reveal shape-dependent structural, optical, electronic and surface properties, providing a powerful insight into the morphological dependence of photocatalytic activity towards methylene blue (MB) degradation. Among these samples, RP, consisting of a cubic Ce-rich phase (Ce_0.6Zr_0.4O₂ nanorods) and a tetragonal Zr-rich phase (Ce_0.2Zr_0.8O₂ nanoparticles), affords the optimal functionality, with a top degradation rate (D = 70.5%) and a peak rate constant (k = 0.0102 min⁻¹). This occurrence results mainly from the prompt separation of excitons and suitable textural properties for MB absorption and activation. A brief introduction to the reaction path when using RP is proposed.