Mitigating polymer-induced self-inhibition with microenvironment-decoupled Sn(II) single-atom catalysts for pollutant...

Area of Science:

• Environmental Chemistry
• Materials Science
• Catalysis

Background:

• Selective oxidation for pollutant removal faces challenges due to competitive adsorption and disrupted redox balance.
• Existing catalysts often exhibit premature termination in pollutant polymerization processes.
• Need for advanced catalytic systems for efficient contaminant removal and resource recovery.

Purpose of the Study:

• To develop a microenvironment-decoupled strategy for precise oxidation regulation in pollutant polymerization.
• To enhance simultaneous contaminant removal and carbon recovery using a novel catalyst.
• To investigate the mechanism of selective pollutant oxidation and polymerization.

Main Methods:

• Anchoring atomically dispersed tin (Sn) on amino-functionalized carbon nanotubes (CNT-NH2).
• Utilizing peroxydisulfate (PDS) as the oxidant.
• Employing in situ spectroscopy and density functional theory (DFT) for mechanistic studies.
• Testing catalyst performance in phenol removal and total organic carbon (TOC) reduction.
• Demonstrating feasibility in a decoupled reactor for continuous water purification.

Main Results:

• The Sn(II)-N4 species selectively activates PDS via a bidentate Sn-PDS complex, favoring an electron-transfer pathway.
• The carbon surface facilitates enrichment of phenolic substrates and their polymerization.
• The SnPc/CNT-NH2/PDS system achieved >95% phenol removal over five cycles and ~82% TOC removal.
• Compared to CNT alone, which showed significantly lower removal efficiencies.
• A decoupled reactor confirmed the system's practical feasibility for continuous water purification.

Conclusions:

• The microenvironment-decoupled strategy effectively regulates oxidation, enabling sustainable pollutant polymerization.
• Atomically dispersed Sn on CNT-NH2 provides a highly selective and stable catalytic system.
• This approach offers a promising paradigm for advanced water purification technologies.