Amorphous Engineering Driving d-Orbital High Spin Configuration for Almost 100% ¹O₂-Mediated Fenton-Like Reactions

Area of Science:

• Materials Science
• Catalysis
• Environmental Chemistry

Background:

• Amorphous materials possess atomic disorder, creating unsaturated sites ideal for single-atom catalyst anchoring.
• Single-atom catalysts (SACs) offer high efficiency and selectivity in chemical reactions.

Purpose of the Study:

• To engineer the electronic structure of isolated cobalt atoms on amorphous carbon nitride (Co-ACN) via substrate amorphization.
• To investigate the catalytic performance of Co-ACN for pazufloxacin (PZF) degradation using peroxymonosulfate (PMS) activation.
• To elucidate the mechanism behind the enhanced catalytic activity and selectivity.

Main Methods:

• Substrate amorphization engineering to create Co-ACN.
• Experimental characterization of Co-ACN electronic structure and coordination environment.
• Kinetic studies for PZF degradation and theoretical calculations (DFT) to understand electronic transitions and reaction mechanisms.

Main Results:

• Co-ACN exhibits a higher coordination environment (Co-N3) compared to crystalline Co-CCN (Co-N2).
• Amorphization engineering induced a transition of cobalt from a low-spin to a high-spin state, optimizing the d-band center.
• Co-ACN achieved near 100% selective singlet oxygen (1O2) generation for rapid PZF removal (k1 = 3.504 min-1) within 1 minute, unlike Co-CCN which produced mixed reactive oxygen species (ROS).

Conclusions:

• Substrate amorphization is an effective strategy to tune the electronic structure of single-atom catalysts.
• The high-spin state of Co atoms on amorphous carbon nitride enhances catalytic activity and selectivity for PZF degradation.
• This work presents a new approach for designing advanced single-atom catalysts by controlling atomic-level electronic properties.