Heterogeneous activation of peroxymonosulfate by hierarchically porous cobalt/iron bimetallic oxide nanosheets for degradation of phenol solutions

Abstract

Bimetallic oxide nanomaterials have received much attention owing to their competing performances in heterogeneous catalysis. Herein, hierarchically porous cobalt-iron oxide nanosheets were successfully prepared using NaBH₄ as a reductant and high concentration cetyl trimethylammonium bromide (CTAB) as a surfactant. Characterization results showed that the CTAB would induce the form of a bilayer structure while NaBH₄ would promote the generation of enriched oxygen vacancies. As a result, the as-prepared Co₁Fe₁-300 exhibited high activity for activating peroxymonosulfate and achieved 100% phenol degradation within 30 min. This excellent catalytic activity can be attributed to its hierarchically porous structure, more active sites and oxygen vacancies. Co leaching test indicated that the Co₁Fe₁-300 exhibited excellent catalytic stability. Mechanistic studies suggested that two main degradation pathways were involved during phenol oxidation process, in which SO₄^•- played a significant role. This work may offer a novel strategy for the synthesis of high activity catalysts and a promising system for the remediation of environmental pollutant.

Keywords: Cobalt iron oxides; Hierarchically porous structure; Oxygen vacancies; Peroxymonosulfate; Sulfate radicals.