Ultra‐Efficient Bamboo Microfiber Adsorbents for Formaldehyde Purification: Fabricated via In‐Situ Growth of Dual Metal‐Organic Frameworks

An innovative strategy of heterointerface-driven formaldehyde capture was developed by dual metal organic framework (MOF) nanoarchitectures in-situ grown on bamboo microfibers (BMFs). The hierarchical BMF/MOF adsorbents were fabricated using steam-exploded BMFs as cores, followed by the sequential growth of indium-based MOF (MIL-68) on zeolitic imidazolate framework-8 (ZIF-8). This triggered a clear transition in adsorption behavior from physical adsorption to a chemisorption-dominated process, achieving ultra-efficient adsorption capacity of 268.15 mg g^-1 with 19.72 times enhancements over commercial activated carbon (AC). The enhanced mechanism was the synergistic effects on the increase of the specific surface area, the formation of hierarchical pores, the introduction of the pyrrolic N and pyridinic N groups, and the formation of zinc oxide-indium oxide (ZnO-In₂O₃) heterojunction that changed the surface polarity and local electron density of the samples. The strategic hybridization of In₂O₃ and ZnO facilitates their electrostatic interactions with formaldehyde molecules, resulting in a significant increase in adsorption energies, varying from -7.91 kcal mol^-1 (pristine BMF) to -24.28, -18.94, and -34.76 kcal mol^-1 for single ZIF-8, MIL-68, and dual MOF-functionalized systems, respectively, representing remarkable enhancements of 206.95%, 139.43%, and 339.44%. The resultant BMF@MIL-68@ZIF-8-800 adsorbent shows the excellent formaldehyde remediation ability in real indoor scenario.