Peroxidase-like activity of hollow sphere-like FeS2/SC boosted by synergistic action of defects and S–C bonding

• Published in: Dalton transactions : an international journal of inorganic chemistry 2023-03, Vol.52 (12), p.3821-3834
• Main Authors: Tan, Hao, Zhaodong Nan
• Format: Article
• Language: English
• Subjects: Bonding; Carbon; Defects; Electron transfer; Peroxidase; Pyrite; Response surface methodology; Room temperature
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d3dt00044c

Pyrite FeS2 has been applied as a peroxidase due to its easy preparation and low cost. However, the low peroxidase-like (POD) activity limited its wide application. A hollow sphere-like composite (FeS2/SC-5.3%) composed of pyrite FeS2 and sulfur-doped hollow sphere-shaped carbon was synthesized by a facile solvothermal method, where the S-doped carbon was in situ formed during FeS2 formation. The synergistic action such as the defects at the carbon surface and the formation of S–C bonding improved the nanozyme activity. The S–C bonding was a bridge between the carbon and the Fe atom in FeS2, which enhanced the electron transfer between the Fe atom and the carbon and accelerated the conversion from Fe3+ to Fe2+. The optimum experimental conditions were obtained by the response surface methodology (RSM). The POD-like activity of FeS2/SC-5.3% was significantly improved compared to that of FeS2. The Michaelis–Menten constant (Km) of FeS2/SC-5.3% is 80 times lower than that of horseradish peroxidase (HRP, natural enzyme). FeS2/SC-5.3% can be used to detect cysteine (Cys) with a limit of detection (LOD) as small as 0.061 μM at room temperature in only 1 min.