Synergistic effect of donor-acceptor structure and built-in electric field in hollow-spherical carbon nitride homojunction towards effective charge transfer and excellent photocatalytic hydrogen evolution performance

Polymeric carbon nitride (PCN) is regarded as a most promising photocatalyst, but the severe recombination of electron-hole pairs restrains its photocatalytic performance. Herein, a carbon nitride gradient homojunction with donor–acceptor (D-A) structure was successfully synthesized. The D-A structure promoted the electron delocalization, while gradient K intercalation helped establish a strong internal electric field from the interior to the surface. They synergistically inhibited the recombination of electron-hole pairs and led to fast charge transfer and much enhanced photocatalytic hydrogen evolution (PHE) performance. This work developed a novel method to promote the charge carrier transfer in carbon nitrides, which could provide a new perspective for the design and development of carbon nitride-based homojunctions in the application of PHE.