Graphitic C₆N₆-Supported Dual Cu/Zn Single-Atom Nanozyme Mimicking Allosteric Regulation for Intelligent Switching...

Area of Science:

• Catalysis
• Materials Science
• Nanotechnology

Background:

• Developing self-adaptive artificial devices requires catalysts with switchable functions.
• Existing catalysts often face limitations due to fixed valence states of active centers.
• Reversible catalytic activity is crucial for advanced applications like chemical noses.

Purpose of the Study:

• To engineer a graphitic C6N6-supported dual Cu/Zn single-atom nanozyme (Cu/Zn-C6N6) with light-switchable catalytic functions.
• To investigate the mechanism behind the switchable superoxide dismutase (SOD)-like and peroxidase-like (POD) activities.
• To demonstrate the potential of this nanozyme in a reversible biosensing application.

Main Methods:

• Synthesis of graphitic C6N6-supported dual Cu/Zn single-atom nanozyme.
• Characterization of catalytic activities under dark and light irradiation.
• Experimental analysis and Time-Dependent Density Functional Theory (TD-DFT) calculations.
• Fabrication of a microfluidic chip for biosensing application.

Main Results:

• Cu/Zn-C6N6 demonstrated highly efficient and distinct SOD-like activity in the dark and POD-like activity under light.
• The switch between SOD and POD activities was reversible with over 90% efficiency upon alternating light and dark conditions.
• Light irradiation and Cu/Zn doping ratio were found to modulate the reduction potential and frontier orbital energies, controlling activity.
• Distinct SOD and POD activities originated from the same Cu-Nx active center with different valence states induced by photoreduction.

Conclusions:

• The developed Cu/Zn-C6N6 nanozyme offers a promising platform for catalysts with reversibly switchable functions.
• Photoreduction is a viable mechanism to tune the valence state of single-atom active sites for distinct catalytic activities.
• The nanozyme's application in a microfluidic chip demonstrates its potential for intelligent, reversible biosensing of analytes like xanthine and glucose.