Porous CoO nanoplates with pH-switchable peroxidase- and catalase-like activity.

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.