Molecularly imprinted methylene dianiline polymer/n-TiO2-P25 hybrid for selective visible-light photocatalytic oxidation of benzyl alcohol

Abstract

This study presents the design and fabrication of a molecularly imprinted polymer–semiconductor hybrid photocatalyst, utilizing self-cross-linked 4,4^′-methylenedianiline (MDA) integrated with n-TiO₂-P25 nanoparticles, for visible-light-driven oxidation of benzyl alcohol. Both molecularly imprinted (MIPPMDA/n-TiO₂-P25) and non-imprinted (NIPPMDA/n-TiO₂-P25) composites were synthesized and systematically characterized using FT-IR, XRD, FE-SEM, BET, diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) analyses. These analyses confirmed the formation of hybrid structures with favorable optical and surface properties. DRS and PL results suggest that incorporation of 4,4^′-methylenedianiline (PMDA) into the n-TiO₂-P25 system extends the visible-light response and may reduce charge-carrier recombination. Furthermore, molecular imprinting introduced preferential recognition sites, which may enhance the adsorption affinity and photocatalytic selectivity toward benzyl alcohol compared with the non-imprinted counterpart. Under blue LED irradiation and natural sunlight, the MIP composite demonstrated superior photocatalytic performance for benzyl alcohol oxidation, achieving up to 91% conversion within 15 min under blue LED irradiation. The improved performance may be associated with the combined effects of preferential molecular recognition and favorable charge-transfer behavior within the polymer–n-TiO₂-P25 hybrid system. Overall, these findings underscore molecular imprinting as a promising approach for developing visible-light-responsive and selective polymer–inorganic hybrid photocatalysts for targeted organic oxidation reactions.

Graphical abstract