Ti3C2 MXenes with intrinsic peroxidase-like activity for label-free and colorimetric sensing of proteins

•Ti3C2 NSs were synthesized using intercalated micromolecule method.•Ti3C2 NSs were found to possess intrinsic peroxidase-like activity.•ssDNA adsorbed on the Ti3C2 NSs can boost the catalytic activity.•The colorimetric method for protein was constructed based on Ti3C2@ssDNA.•The method is easy to prepare and cost efficient.