A Facile synthesis of superparamagnetic Fe3O4 nanofibers with superior peroxidase-like catalytic activity for sensitive colorimetric detection of l-cysteine

•A facile strategy has been successfully developed to prepare superparamagnetic Fe3O4 nanofibers.•The as-prepared Fe3O4 nanofibers showed a better peroxidase-like catalytic activity than commercial Fe3O4 nanoparticles.•An effective sensing platform for the detection of l-cysteine with a high sensitivity and selectivity has been demonstrated.