Eco-friendly immobilization of metal-doped ZIF-8 onto bamboo cellulose scaffolds as recyclable carbonic anhydrase mimics.

Zeolitic imidazolate framework-8 (ZIF-8) developed as carbonic anhydrase mimics for CO2 capture currently suffers from insufficient catalytic activity, stability and recyclability. In this work, metal-doped ZIF-8 with Co2+ or Ni2+ was immobilized on delignified bamboo cellulose scaffolds (DBS) via in situ mineralization to create recyclable efficient biomimetic catalysts. The successful synthesis of DBS-supported ZIF-8 was confirmed through scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and infrared spectroscopy, with metal doping ratios optimized to Co2+/Zn2+ (3:2) and Ni2+/Zn2+ (1:1) for maximum activity. Ni/ZIF 8@DBS composite exhibited superior activity and CO2 hydration rates, surpassing free Ni/ZIF-8 and Co/ZIF-8@DBS. In addition, DBS immobilization enhanced stability, retaining ∼60 % activity under alkaline conditions after 12 h and ∼50 % under continuous flow for 24 h. Overall, Ni2+/Co2+ doping and DBS immobilization improved ZIF-8 catalytic efficiency, stability and recyclability, demonstrating promising potential for industrial CO2 capture through catalytic hydration.