Cu2+-modified hollow carbon nanospheres: an unusual nanozyme with enhanced peroxidase-like activity.

Abstract

ACu2+-modified carboxylated hollow carbon nanospheres (Cu2+-HCNSs-COOH) was designedwith enhanced peroxidase-like activity for the detection of hydrogen peroxide (H2O2) and degradation of methylene blue (MB). Hollow polymer nanospheres were fabricated from aniline, pyrrole, Triton-100, and ammonium persulfate via confined interfacial copolymerization reaction, which can be pyrolyzed to create HCNSs with the hollow gap diameter of about 20nm under high temperature. Combining the synergistic effect of coordination and electrostatic interaction, Cu2+-HCNSs-COOH was constructed by anchoring Cu2+ on the surface of HCNSs-COOH. Furthermore, Cu2+-HCNSs-COOH has higher affinity for 3,3',5,5'-tetramethylbenzidine and H2O2 of 0.20mM and 0.88mM, respectively. Based on the rapid response of Cu2+-HCNSs-COOH to H2O2, we constructed acolorimetric sensing platform by detecting the absorbance of the3,3',5,5'-tetramethylbenzidine-H2O2 system at 652nm for quantifying H2O2, which holds good linear relationship between 1 and 150μM and has adetection limit of 0.61μM. We alsoinvestigated the degradation of MB in the presence of Cu2+-HCNSs-COOH and H2O2, which can degrade 80.7% pollutants within 30min. This research developed an unusual nanozyme for bioassays and water pollution treatment, which broadened the way for the rapid development of clinical diagnostics and water pollution treatment.