Porous Phenazine-bridged Tetraoxa[8]Circulenes for Selective Gold Recovery and Heterogeneous Catalysis

Area of Science:

• Materials Science
• Green Chemistry
• Catalysis

Background:

• Sustainable recovery of precious metals is crucial for resource security and environmental protection.
• Selective gold recovery from electronic waste is a significant challenge.
• Developing advanced materials for efficient metal capture and catalysis is essential.

Purpose of the Study:

• To synthesize a novel phenazine-based porous material, PpTOC, for efficient gold capture.
• To investigate the catalytic activity and selectivity of the recovered gold species.
• To explore solvent-induced divergent selectivity in catalysis using the same heterogeneous material.

Main Methods:

• Synthesis of phenazine-based porous tetraoxa[8]circulene (PpTOC).
• Gold capture experiments from electronic waste simulants and real waste.
• Characterization of the gold-loaded material.
• Evaluation of the material as a heterogeneous catalyst in alkylation-annulation reactions with varying solvents.

Main Results:

• PpTOC exhibits a high surface area (>1200 m²/g) and efficient gold uptake capacity (up to 860 mg/g).
• The material selectively recovers gold from electronic waste, even with high copper concentrations.
• The recovered gold species act as a heterogeneous catalyst, demonstrating solvent-dependent selectivity (alkylation in toluene, annulation in ethanol).

Conclusions:

• Phenazine-based porous tetraoxa[8]circulene (PpTOC) is a highly effective material for selective gold recovery from electronic waste.
• The gold-loaded PpTOC serves as a versatile heterogeneous catalyst with tunable selectivity based on solvent choice.
• This work offers a sustainable approach for precious metal recovery and advanced catalytic applications.