Dynamic oxygen vacancy engineering on CuO via refreshable catalytic surface for high-efficient water decontamination.

Area of Science:

• Environmental Chemistry
• Materials Science
• Catalysis

Background:

• Oxygen vacancies (O_v) on metal oxides are crucial for peroxymonosulfate (PMS) activation in wastewater treatment.
• In-situ regeneration of these O_v is essential for sustained catalytic activity but remains challenging.

Purpose of the Study:

• To develop a method for in-situ real-time regeneration of O_v on CuO surfaces.
• To investigate the synergistic effects of surface hydroxyl groups and O_v on catalytic activity.
• To enhance the degradation of sulfamethoxazole (SMX) using the regenerated catalyst system.

Main Methods:

• Alkali etching of CuO to introduce surface hydroxyl groups.
• In-situ regeneration of O_v during the catalytic process.
• Density functional theory (DFT) calculations to understand reaction mechanisms.
• Experimental degradation studies using sulfamethoxazole (SMX) as a model pollutant.

Main Results:

• Alkali treatment significantly reduced O_v formation energy on CuO from 1.60 eV to 0.38 eV.
• Synergy between hydroxyl groups and O_v enhanced electron transfer to PMS, increasing SMX degradation by 42 times.
• Sulfate and hydroxyl radicals were identified as the primary reactive oxygen species.
• The OH^-/CuO/PMS system demonstrated over 300 hours of stability in a real water matrix.

Conclusions:

• A simple and effective method for in-situ O_v regeneration on CuO was established.
• The synergistic effect of hydroxyl groups and O_v is key to enhanced catalytic performance.
• This approach offers a promising strategy for sustainable wastewater treatment via catalyst regeneration.