Single-Atom-Thick Active Layers Realized in Nanolaminated Ti₃(Al_<i>x</i>Cu_1–<i>x</i>)C₂ and Its Artificial Enzyme Behavior

Abstract

A Ti₃(Al_<i>x</i>Cu_1-<i>x</i>)C₂ phase with Cu atoms with a degree of ordering in the A plane is synthesized through the A site replacement reaction in CuCl₂ molten salt. The weakly bonded single-atom-thick Cu layers in a Ti₃(Al_<i>x</i>Cu_1-<i>x</i>)C₂ MAX phase provide actives sites for catalysis chemistry. As-synthesized Ti₃(Al_<i>x</i>Cu_1-<i>x</i>)C₂ presents unusual peroxidase-like catalytic activity similar to that of natural enzymes. A fabricated Ti₃(Al_<i>x</i>Cu_1-<i>x</i>)C₂/chitosan/glassy carbon electrode biosensor prototype also exhibits a low detection limit in the electrochemical sensing of H₂O₂. These results have broad implications for property tailoring in a nanolaminated MAX phase by replacing the A site with late transition elements.