Zeolite-13X loaded strong stable CoO single-atom catalysts for efficient peroxomonosulfate activation: Role of magnesium silicate and SiOH bonding

Abstract

Cobalt-based catalysts exhibit high activity in the removal of water pollutants. However, their practical application is significantly impeded by potential biotoxicity and stability issues. How to simply stabilize cobalt atoms at the carrier interface remains a challenge. Here, we loaded cobalt into zeolite-13X and coated thin nanosheets of magnesium silicate with 3D floral morphology on the Co/13X surface through hydrothermal treatment. Temperature-controlled calcination successfully stabilized the Co atoms by utilizing Si-OH groups on the surface of zeolite-13X, resulting in the formation of an efficient and stable CoO single-atom catalyst (600CoMg/13X). Characterization analyses including FT-IR, XPS, and XAFS confirmed that magnesium silicate played a crucial role in this process. Characterization analyses using BET, SEM and TEM revealed that 600CoMg/13X possesses a highly developed porous structure with a Brunauer-Emmett-Teller (BET) specific surface area of 364.903 m²/g. During peroxymonosulfate (PMS) activation for tetracycline (TC) degradation, the 13X stretcher-loaded CoO single atom catalyst exhibited excellent catalytic performance and stability. A TC removal rate exceeding 98 % was achieved within 10 min while maintaining a TC removal rate of 95.5 % after eight cycles of degradation. Furthermore, under real aqueous environmental conditions, the 600CoMg/13X catalyst demonstrated stable degradation performance and low biotoxicity. This work provides valuable insights into establishing stable bonding at metal-zeolite interfaces and offers a feasible methodology for developing efficient and environmentally friendly cobalt-based catalysts.