The development of high-efficiency peroxidase mimetics is highly desirable in view of high cost and low stability of natural enzymes.From the perspective of mimicking active site microenvironment at low cost,we herein report a novel histidine-functionalized graphene quantum dot (His-GQD)/hemin complex,which exhibits the highest catalytic rate for the peroxidase-based chromogenic reaction among the hemin-containing mimetics reported so far.Also,our peroxidase mimetic shows excellent tolerance to strongly acidic conditions and can function in a wide temperature range.Lineweaver-Burk plots and comprehensive electron paramagnetic resonance analysis reveal a ping-pong type catalytic mechanism for this mimetic.In addition,His-GQD/hemin demonstrates high efficiency and accuracy in detecting H2O2 and blood glucose.Our work provides an effective design of artificial enzymes for practical applications.