Axially Coordinated Gold Nanoclusters Tailoring Fe–N–C Nanozymes for Enhanced Oxidase-Like Specificity and Activity

Abstract

Metal–organic frameworks (MOF) derived nitrogen-doped carbon-supported monodisperse Fe (Fe–N–C) catalysts are intensively studied, but great challenges remain in understanding the relationship between the coordination structure and the performance of Fe–N–C nanozymes. Herein, a novel nanocluster ligand-bridging strategy is proposed for constructing Fe-S₁N₄ structures with axially coordinated S and Au nanoclusters on ZIF-8 derived Fe–N–C (labeled Au_x/Fe-S₁N₄-C). The axial Au nanoclusters facilitate electron transfer to Fe active sites, utilizing the bridging ligand S as a medium, thereby enhancing the oxygen adsorption capacity of composite nanozymes. Compared to Fe-N-C, Au_x/Fe-S₁N₄-C exhibits high oxidase-like specificity and activity, and holds great potential for detecting acetylcholinesterase activity with a detection limit of 5.1 µU mL⁻¹, surpassing most reported nanozymes.