The introduction of L-phenylalanine resulting in a notable optimization of the bandgap structure, the utilization of photocarriers and the generation of ROS of HCPs H₃LP-HCPs, and achieving close to 100 % conversion efficiency and 100 % selectivity toward benzylamine oxidation with a high yield of H₂O₂ (9.2 mmol ⋅ g_cat ⁻¹ ⋅ h⁻¹) under 455 nm LED lamp in air.

Abstract

The simultaneous production of imine and hydrogen peroxide (H₂O₂) via photocatalytic aerobic amine oxidation is a bright way to obtain value added products, however, rapid recombination of photogenerated charge leads to low conversion efficiency and selectivity. Herein, a metal-free amino acid modified hyper-cross-linked polymer (H₃LP-HCPs) photocatalyst was synthesized for photocatalytic amines oxidation by regulating the ratio of L-phenylalanine (L-Phe) and hexaphenylbenzene (Hex). The results showed that the H₃LP-HCPs photocatalyst with 1 : 3 molar ratio of L-Phe and Hex achieves close to 100 % conversion efficiency and 100 % selectivity toward benzylamine oxidation under 455 nm blue LED lamp irradiation. Furthermore, a high yield of H₂O₂ (9.2 mmol ⋅ g_cat ⁻¹ ⋅ h⁻¹) was synchronously obtained in benzylamine oxidation. Experiments and time-dependent density functional theory calculation results revealed that the N-functional groups in H₃LP-HCPs photocatalyst not only remarkably broadens light-response range, but also facilitates electrons transfer from L-Phe to the Hex, thus accelerating photogenerated charge separation efficiency and the formation of reactive oxygen species (ROS).