Tuning the polymerization degree of 3-aminophenol-formaldehyde for photocatalytic degradation of methylene blue

The influence of polymerization degree on photocatalytic performance and light utilization efficiency in non-metallic photocatalysis has been comparatively underexplored. In this study, by varying the synthesis duration of 3-aminophenol-formaldehyde particles, we successfully obtained non-metallic photocatalysts with different degrees of polymerization and evaluated their methylene blue degradation efficiency. Results reveal that particles synthesized for 10 minutes exhibit the lowest polymerization degree and a narrower bandgap of 1.81 eV. Compared to those prepared over 30 and 360 minutes, the 10-minute sample enhanced the methylene blue degradation rate by 23.2% and 27.5%, respectively. These low-molecular-weight 3-aminophenol-formaldehyde particles achieved up to 99% degradation efficiency and demonstrated high utilization efficiency of the light source. The degradation process followed the Elovich kinetic model, indicating a heterogeneous, multipath reaction mechanism. In the AF/MB binary system, the opposite surface charges of acid fuchsin (AF) and 3-aminophenol-formaldehyde particles promote methylene blue (MB) adsorption, thereby enhancing MB degradation. This work offers new insights into how polymerization degree influences the light-harvesting ability and organic pollutant degradation efficiency of non-metallic photocatalysts. • The polymerization degree of APF is precisely controlled by reaction time. • The low polymerization degree enhanced the methylene blue degradation rate by 27.5%. • The low polymerization degree exhibits a narrower bandgap of 1.81 eV.