Hollow and Porous Fe3C-NC Nanoballoons Nanozymes for Cancer Cell H2O2 Detection

•The hollow and porous Fe3C-NC nanoballoons (Fe3C-NC-NBs) are obtained by a novel template-induced strategy.•The Fe3C-NC-NBs has unique structure of a large specific surface area, rich porous structures, a high N and Fe content.•The Fe3C-NC-NBs nanozymes possess intrinsic and excellent peroxidase-like activity including large linear range and low detection limit, good reproducibility and selectivity for detection of H2O2 both in HAc-NaAc buffer solution and released from HeLa cells via a fluorescence assay.