Smart manufacturing of ZIF-8 photonic crystals: Catalytic formaldehyde degradation and colorful eco-friendly coatings

Formaldehyde and other harmful gases cause environmental pollution and threaten human health. Environment-friendly coatings is an effective strategy to address these environmental and health concerns. In this study, a large-scale amorphous photonic crystals (APC) based on modified ZIF-8 (H_xh-ZIF-8) with photocatalytic degradation of formaldehyde and tunable structural color were designed for eco-friendly coatings by programmable smart manufacturing. As APC unit, H_xh-ZIF-8 nanoparticles with controllable diameters were synthesized utilizing solvothermal method and the −N = C = O group was introduced with thermal oxidation. The results of photocatalytic degradation revealed that H_5h-ZIF-8, through thermal oxidation, exhibited a formaldehyde degradation rate 9.8 times than that of ZIF-8. The main reactive components in photocatalysis were holes (h⁺) and superoxide radicals (^·O₂^–), showcasing both stability and reproducibility. The color and brightness of the APC were adjusted by tuning the H_xh-ZIF-8 diameter. The angle-independent APC ranging from red to purple were fabricated with 177, 165 and 235 nm H_xh-ZIF-8 nanoparticles in various proportions with programmable smart manufacturing. In this study, a large-scale ZIF-8-based APC was designed with programmable smart manufacturing for environment-friendly coating, which combined environmental protection technology with structural color, and paved a new strategy for the development of multifunctional materials in air quality management.