Dual-engineered Jahn-Teller/confinement synergy in asymmetric chlorinated Janus graphene for ultra-selective gold recovery from E-waste

The development of selective adsorbents with precise ion recognition capability remains crucial for sustainable gold recovery from electronic waste. We systematically studied the hydration process of gold, silver, and copper ions, confirming the unique stable planar hydration structure specific to gold ions. Based on the microscopic inverse design theory, we propose an asymmetric chlorination strategy to construct Janus bilayer graphene with a dual selection mechanism (confinement effect and high gold affinity). Among them, C₁₂Cl₅ exhibits exceptional thermal stability, a high theoretical adsorption capacity (1225 mg g⁻¹, surpassing recently reported adsorbents in gold adsorption performance), optimal application conditions at 40 °C and pH = 1, and excellent selectivity in mixed pollutant solutions. These advantages originate from the low diffusion barrier for water-soluble cations entering the interlayer and the high crystal field stabilization energy of weak-field ligands coordinating with gold. This dual-mechanism design paradigm establishes chlorinated graphene as a next-generation gold extraction platform, providing both theoretical foundations for hydration structure-adsorption correlations and practical guidelines for industrial wastewater treatment processes.