Hierarchical flower-like Co2TiO4 nanosheets with unique structural and compositional advantages to boost peroxymonosulfate activation for degradation of organic pollutants

Abstract

In this study, cobalt titanate spinel (Co₂TiO₄) with an unprecedented hierarchical structure was synthesized via a simple one-pot hydrothermal route and demonstrated to be an effective heterogeneous catalyst in peroxymonosulfate (PMS) activation for degradation of organic pollutants. The as-synthesized Co₂TiO₄ was well assembled by two-dimensional nanosheets, exhibiting a well-defined three-dimensional flower-like architecture with a large surface area (113.6 m² g⁻¹) and highly open porous structure. In particular, the Ti element in Co₂TiO₄ was identified as a promoter that impelled Co sites to provide high affinity, easy electron transfer, and strong bond-weakening ability for PMS, which actually led to a boosted catalytic activity. Benefiting from the unique three-in-one feature (high-level exposure of active sites, favorable mass transfer of guest species, and strong activation ability), the Co₂TiO₄ catalyst manifested an excellent catalytic efficiency in PMS activation, enabling complete removal of the antibiotic ofloxacin in a short period of time, which was significantly superior to various conventional heterogeneous cobalt-based catalysts.