Spatial separation of redox centers for boosting cooperative photocatalytic hydrogen evolution with oxidation coupling of benzylamine over Pt@UiO-66-NH2@ZnIn2S4

Abstract

The construction of an overall photocatalytic redox system through the combination of photocatalytic hydrogen evolution (PHE) with the oxidative coupling of benzylamine into imines is highly desirable. Herein, a yolk–shell heterojunction Pt@UiO-66-NH₂@ZnIn₂S₄ (Pt@UiO-66-NH₂@ZIS) is synthesized and successfully utilized as a dual-functional photocatalyst for C–N coupling reaction of benzylamine and proton reduction half-reaction. In this dual-catalytic system, the hole collector ZnIn₂S₄ can trap and release the holes of UiO-66-NH₂ to accelerate the C–N coupling reaction, while the electron collector Pt acts as an electron collector and an active site for the reduction of protons to H₂. As expected, Pt@UiO-66-NH₂@ZIS shows 4 and 16 times higher catalytic activities than that of individual ZnIn₂S₄ and UiO-66-NH₂, respectively. Consequently, the optimal photocatalyst simultaneously promotes C–N coupling reaction (78%) and H₂ evolution (850 μmol g⁻¹ h⁻¹). This unique design offers great prospects for other highly efficient synergistic dual-functional photocatalytic systems.