Enzyme-Mimetic Manganese Porphyrin/TiO 2 S-Scheme Heterojunctions for Photocatalytic H 2 O 2 Generation Coupled With Polymer Synthesis

Photocatalytic O 2 reduction to H 2 O 2, coupled with selective alcohol oxidation, represents an efficient strategy for utilizing photogenerated electrons and holes. However, the oxidation of alcohols to aldehydes followed by further in situ functionalization into a high economic value polymer in a single photocatalytic system remains unexplored. Herein, we construct an S-scheme heterojunction between biomimetic Mn(III) tetra(4-carboxylphenyl)porphyrin (TCPP(Mn)) and TiO 2 nanoparticles for visible-light-driven photocatalytic production of H 2 O 2 coupled with polymer synthesis. The TCPP(Mn)/TiO 2 heterojunction delivers high production rates of 4563 and 4225 μmol·g −1 ·h −1 for H 2 O 2 and benzaldehyde, respectively. More importantly, the photocatalytic generation of H 2 O 2 coupled with the oxidation of methanol to formaldehyde, followed by in situ condensation with urea to yield urea-formaldehyde resins over TCPP(Mn)/TiO 2 heterojunctions, was further demonstrated. Mechanistic investigations reveal that the TCPP(Mn)/TiO 2 S-scheme heterojunctions possess great merits of fast charge separation, high redox potentials, and enzyme-mimetic active sites, efficiently boosting the photocatalytic generation of value-added H 2 O 2 and urea-formaldehyde resins. This work provides a generalizable strategy for designing advanced heterojunction photocatalysts for H 2 O 2 production coupled with polymer synthesis.