Boosting photocatalytic hydrogen peroxide evolution through aerobic oxidative dehydrogenation of benzyl alcohol over amino acid hyper-cross-linked polymer in two-phase system

Abstract

The fusion of photocatalytic hydrogen peroxide (H2O2) production with the generation of high-value organic compounds carries the potential to optimize the utilization of solar energy. The efficient generation and separation of products constitute indispensable elements in constructing a proficient reaction system. Herein, the photocatalytic production of H2O2 via the aerobic oxidative dehydrogenation of benzyl alcohol (BA) was realized through the application of an amino acid hyper-cross-linked polymer (H6P-HCPs) in two-phase system. The outcomes unveiled that the H6P-HCPs with 1:6 M ratio of L-phenylalanine (L-Phe) and hexaphenylbenzene (HPB) achieves the highest generation rate of H2O2 (29.26 mmol∙gcat-1∙h-1), stoichiometric amount of benzyl alcohol oxidation products were obtained as 96% benzaldehyde (23.94 mmol∙gcat-1∙h-1) and 4% benzoic acid (5.56 mmol∙gcat-1∙h-1). Time-dependent density functional theory (TDDFT) calculations illuminated that the presence of L-Phe monomers of H6P-HCPs not only facilitated electron transfer from L-Phe to HPB, capitalizing on electronegativity differentials, but also instigated the formation of O2•- while concurrently adjusting its hydrophobic nature. These factors, in concert, were instrumental in the accomplishment of this highly efficient photocatalytic process.