Bionic structural design of Pt nanozymes with the nano-confined effect for the precise recognition of copper ion

Geometric architecture with the function of initiating catalysis and determining selectivity in natural enzyme is a fascinating issue. The modulation of the geometric architecture has been demonstrated as an effective approach to improve the catalytic performance of nanozymes. In this work, Pt nanozymes with bionic structure were finely tuned to form substrate channels (1–2 nm) by dealloying Ni in the Ni2Pt nanoparticles. The nano-confined effect can create an apparent potential between substrate channels and the surface of Pt nanozymes, while the concaves on Pt nanozymes can form defects to create unbalance on the CN bond and enhance the migration of ions. The density function theory calculation indicated that Pt nanozymes possessed the higher capacity for the absorption of copper ions, thus copper ions can be spontaneously and specifically absorbed in substrate channels and then reduced at a micro potential of −26 mV. A "sensor in the pocket" was realized for the on-site and point-of-care recognition of copper ions over a range from 0.01 mM to 100 mM. Herein, Pt nanozymes offer a deep insight into the geometric architecture of natural enzyme and provides potential application in miniaturized instruments.