Co₄N Nanowires: Noble-Metal-Free Peroxidase Mimetic with Excellent Salt- and Temperature-Resistant Abilities

Abstract

Compared to natural enzymes, nanomaterial-based artificial enzymes have attracted immense attention because of their high stability and cost-effectiveness. In this study, cobalt nitride (Co₄N) as a noble-metal-free artificial enzyme exhibiting highly intrinsic peroxidase-like activity and good stability was reported. Kinetic studies revealed that the resultant Co₄N nanowires (NWs) exhibited a stronger affinity for 3,3',5,5'-tetramethylbenzidine (TMB) and H₂O₂ than HRP. Compared to Co₃O₄ NWs, Co₄N NWs exhibited highly improved catalytic activities, with H₂O₂ exhibiting an apparent K_m approximately 2 orders of magnitude less than that of Co₃O₄. In particular, the peroxidase-like activity of Co₄N was maintained well over a wide range of temperatures and ionic strength. A Co₄N-based method was further developed for the detection of glucose with good sensitivity and reliability. Because of advantages such as easy storage, cost-effectiveness, high sensitivity, and outstanding stability, Co₄N NWs demonstrate the potential for replacing noble-metal-based peroxidase mimetics in a wide range of promising applications.