“…Due to the high catalytic activity, low cost, easy storage, and high stability, nanoenzymes have attracted attention after the discovery of Fe 3 O 4 with similar activity to that of horseradish peroxidase (HRP). [1][2][3] Transition metal sulfides (TMSs) have been studied as nanozymes ( peroxidase) due to their easy preparation and low cost. [4][5][6][7][8] However, the low peroxidase-like (POD) activity induced a high concentration of H 2 O 2 to oxidize 3,3′,5,5′-tetramethylbenzidine (TMB, colorless) to oxTMB (blue).…”