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