Hemin-functionalized MoS2 nanosheets: enhanced peroxidase-like catalytic activity with a steady state in aqueous solution

Abstract

Hemin-functionalized MoS₂ nanosheets (hemin/MoS₂-NSs) are first obtained via van der Waals interactions between few-layered MoS₂ nanosheets (MoS₂-NSs) and hemin molecules. It is demonstrated that a portion of MoS₂-NSs undergoes a phase transition from semiconducting to metallic phase under the influence of hemin, which shows the coexistence of semiconducting and metallic phases in the crystal structure of hemin/MoS₂-NSs. MoS₂-NSs prepared from sonication-induced exfoliation of bulk MoS₂ crystals in aqueous surfactant solution exhibit intrinsic peroxidase-like activity for the oxidation of 3,3,5,5-tetramethylbenzidine in the presence of H₂O₂, which is further improved by the functionalization of hemin. Significantly, MoS₂-NSs are presented as a new support of hemin, and when compared to MoS₂-NSs, hemin/MoS₂-NSs exhibit better dispersity in aqueous solution, which is used in the development of H₂O₂ sensor based on the enhanced peroxidase-like activity.