Nanoscale p–n junction integration via the synergetic hybridization of facet-controlled Cu₂O and defect-modulated g-C₃N_4-x atomic layers for enhanced photocatalytic water splitting

Tailoring multidimensional heterostructure interface in nanoscale with robust electronic configuration and regulated charge steering is of great significance for photocatalysis. In this contribution, an effective p–n heterojunction nanocomposites were formulated by hybridizing N-deficient g-C₃N₄ atomic layers (g-C₃N_4-x) and rhombic dodecahedral Cu₂O with controlled facets. The concomitant outcomes from the p–n junction induce a built-in electric field that propel the atomic-level directional charge transfer and accommodate electrons and holes at separated locations of n-type g-C₃N_4-x and p-type Cu₂O, respectively. This substantially enhances the electron–hole pairs separation and prolongs the lifetime of charge carriers. As a result, the best performing 3 wt% Cu₂O/g-C₃N_4-x sample demonstrated an exceptional photocatalytic H₂ evolution rate of 420.3 μmol/g/h under visible light irradiation, which is 1.8-fold augmentation in contrast to the individual counterpart (g-C₃N_4-x). In brief, this work presents a powerful strategy to modulate the interaction of heterointerface in achieving highly efficient photocatalytic application.