Enhanced Fenton-catalytic efficiency by highly accessible active sites on dandelion-like copper–aluminum–silica nanospheres for water purification

Abstract

A novel Fenton catalyst consisting of dandelion-like copper–aluminum–silica nanospheres (DCAS Ns) was successfully prepared via a hydrothermal process for the first time. This catalyst exhibited exceptionally high activity and stability for the degradation and mineralization of various refractory pollutants, as demonstrated with phenol, pharmaceuticals, pesticides, dyes and endocrine disrupting chemicals at neutral pH. The reaction rate was 5.2–13.4 times higher than that of the conventional Fenton catalysts. Moreover, the utilization efficiency of H₂O₂ was as high as 86.7%. According to the characterization, DCAS Ns possessed a unique fibrous structure arranged in three dimensions to form nanospheres, just like dandelion flowers. Cu and Al were co-incorporated into the framework of the fibrous silica nanospheres with Si–O–Cu and Al–O–Cu, resulting in great exposure, significant accessibility and high stability of the surface Cu, which were responsible for the outstanding Fenton catalytic performance of DCAS Ns. In addition, the formation of Cu²⁺–O–AP complexes inhibited the generation of HO₂˙/O₂˙⁻ and O₂ and promoted the generation of ˙OH during the Fenton reaction, resulting in the high utilization efficiency of H₂O₂ in the DCAS Ns Fenton system. These findings thus provide a new insight into the design and application of high-efficiency Fenton catalysts for water purification.