Design of Photocatalytic Composite Coatings for Formaldehyde Removal Based on the Visual Effects of Wood Furniture

Constructing photocatalytic composite coatings to remove indoor formaldehyde (HCHO) is an important approach to ensuring a healthy indoor environment. However, most current research focuses primarily on the design of photocatalysts and coatings, while overlooking the impact of applying these coatings to wood surfaces on the visual appearance of furniture. Here, a waterborne polyurethane (WPU) photocatalytic composite coating was developed using four fundamental photocatalyst color systems and applied to four types of wood to examine its influence on color difference and visual appearance. The catalyst's ability and mechanism for efficiently degrading indoor HCHO were verified through material characterization and HCHO degradation experiments. By adjusting the ratios of photocatalysts to construct coatings, both HCHO degradation performance and essential mechanical properties were shown to meet basic requirements. Color-difference analysis and eye-tracking data were used to assess how different photocatalytic composite coatings affect the visual perception of various wood types. Intelligent design processes were developed using an XGBoost classifier based on gradient‑boosted decision trees and a Bayesian‑optimized inverse design framework. This system proposes an intelligent design framework for photocatalytic composite coatings for wooden furniture, aiming to provide more methodological references.