Controllable synthesis of boron-doped Zn–N–C single-atom nanozymes for the ultrasensitive colorimetric detection of p-phenylenediamine

Single-atom catalysts with atomically dispersed M-Nx active sites have been widely used as nanozymes for colorimetric sensing due to their similar structure to natural enzymes , but they are still limited by their biological activity. Herein, controllable synthesis of B-doped Zn–N–C (ZnBNC) single-atom nanozymes (SAzymes) was designed and realized for the first time as a potent peroxidase mimetic. Based on the peroxidase-like activity of ZnBNC SAzymes, a novel colorimetric method was developed for the highly sensitive and selective detection of p-phenylenediamine (PPD) with a wide response range (0.3–10 μM) and a low detection limit (0.1 μM), which can be used as an alternative method for the detection of PPD in hair dyes and dyed hair samples.