Functional Groups‐Dependent Tp‐Based COF/MgIn₂S₄ S‐Scheme Heterojunction for Photocatalytic Hydrogen Evolution

Abstract An effective technique for improving the photocatalytic activity is the functional‐group‐oriented approach of covalent organic frameworks (COFs). However, the creation of the functional groups‐dependent COF‐based S‐scheme heterojunction has seldom been reported. In this study, two distinct Tp‐based COFs with different functional groups using a solvothermal technique, TpPa‐1 with −H and TpPa‐2 with −Me (methyl), respectively, is synthesized. Moreover, functional groups‐dependent Tp‐based COF/MgIn₂S₄ (MIS) S‐scheme heterojunctions (i.e., TpPa‐1/MIS and TpPa‐2/MIS) are created to clarify the dynamics of photoinduced charges and boost the photocatalytic H₂ evolution. Notably, the photocatalytic H₂ evolution of the optimum TpPa‐1/MIS‐5% (13.16 mmol g⁻¹ h⁻¹) is 4.3 times greater than that of TpPa‐2/MIS‐5% (3.05 mmol g⁻¹ h⁻¹), which is attributed to the −Me functional groups in TpPa‐2 that could slow down the interfacial photogenerated electron‐transfer and make its surface less hydrophilic, resulting in the lower photocatalytic activity for H₂ evolution over TpPa‐2/MIS‐5%. On the contrary, the remarkable activity for H₂ evolution in TpPa‐1/MIS‐5% is associated with its fast interfacial photogenerated electron transfer from MIS to TpPa‐1 due to the hydrophilic −H functional groups in TpPa‐1, which induced to a stronger internal electric field motivated by the construction of S‐scheme heterojunction.