▎ 摘　　要

Exploring peroxidase-like nanozymes with high catalytic activity is an urgent task to construct a fast, convenient, and selective colorimetric sensing platform. In this work, a nanozyme, 5,10,15,20-tetrakis(4-carboxyl phenyl)porphyrin-functionalized NiS2 nanoparticles, anchored on the surface of graphene (Por-NiS2/GO) was designed. Compared with NiS2 nanoparticles anchored on the surface of graphene (NiS2/GO), Por-NiS2/GO had a higher peroxidase-like activity due to the introduction of porphyrin. The size of NiS2 nanoparticles was about 110-250 nm. The peroxidase-like behaviors of PorNiS(2)/GO were evaluated using the chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) with a fast-blue color change in less than 1 min. Electron spin resonance (ESR) data revealed that the excellent performance of Por-NiS2/GO was due to the active oxygen species produced, including hydroxyl radical (OH) and superoxide radical (center dot O-2(-)), during the catalytic reaction, owing to the synergetic effect among different components including porphyrin, NiS2, and GO. Thus, based on the enhanced peroxidase-like activity of Por-NiS2/GO, a fast, sensitive, and selective colorimetric sensing platform of H2O2 has been constructed, and furthermore, a sensing platform for cholesterol was also developed coupled with cholesterol oxidase (ChOx). The colorimetric sensing platform was validated by detecting cholesterol in serum samples.