Engineering S-scheme mCN@mPDIP molecular heterojunction with highly efficient interface charge transfer for photocatalytic aerobic oxidation synthesis.

[Display omitted] • A mCN@mPDIP molecular heterojunction is designed for facilitating intimate interface contact and promoting highly efficient interfacial charge transfer. • The S-scheme photogenerated charge transfer mechanism was revealed by in situ irradiated X-ray photoelectron spectroscopy. • The charge separation efficiency of the molecular heterojunction surpasses that of both bulk and nano heterojunctions. • The mCN@mPDIP achieves efficient aerobic oxidation of methyl phenyl sulfide into sulfoxide with a complete conversion of 99.3 % and selectivity of 99.2 %. The construction of S-scheme heterojunctions, which offers a promising approach for spatially separating photogenerated charge carriers with high redox potentials and multimolecular activation, represents a viable modification strategy in photocatalytic applications. However, the prevalent insufficient contact areas between two components result in low interface charge transfer efficiency, thereby impeding the photocatalytic performance of such heterostructures. Herein, we address this limitation by introducing a unique mCN@mPDIP molecular heterojunction through a pH-triggered molecule self-assembly eutectoid technique, enabling intimate interface contact and promoting highly efficient interfacial charge transfer following an S-scheme mechanism. Consequently, the mCN@mPDIP molecular heterojunction achieves significantly improved charge separation efficiency and higher concentration of active carriers compared to typical bCN-bPDIP bulk heterojunction and nCN/nPDIP nano heterojunction. Combined with the effective sulfide activation on mPDIP sites and O 2 activation on mCN sites, the resulting mCN@mPDIP demonstrates outstanding activity in the photocatalytic aerobic oxidation of sulfides into sulfoxides without any redox mediators. [ABSTRACT FROM AUTHOR]