Porous Co3O4 nanoplates with pH-switchable peroxidase- and catalase-like activity

Abstract

Porous Co₃O₄ nanoplates were synthesized via a soft template method. By using amphiphilic block copolymer F127 colloids as the pore producer, porous Co(OH)₂ nanoplates were prepared. After the annealing procedure, the obtained Co₃O₄ reserved the hexagonal shape and a similar size to the Co(OH)₂ precursor. The as-prepared porous Co₃O₄ nanoplates named Co₃O₄-F simultaneously possessed peroxidase and catalase mimetic activities. Interestingly, these two kinds of mimetic enzyme activities could be switched by pH. Meanwhile, temperature and the concentrations of Co₃O₄-F had a significant effect on the switch pH and the dual-enzyme mimetic catalytic ability. Moreover, Co₃O₄-F exhibited good peroxidase-like catalytic activity even in the neutral pH system, providing a new strategy for one-step analysis of glucose. A novel one-step colorimetric glucose biosensor was fabricated based on the Co₃O₄-F nanozyme, making the operation of detection simpler and easier.