Constructing creatinine-derived moiety as donor block for carbon nitride photocatalyst with extended absorption and spatial charge separation.

[Display omitted] • The chemical structure of the intermediates from urea and creatinine was confirmed by the MALDI-TOF-MS spectra. • The theoretical study revealed that the formation of the donor block results in an extended optical absorption and spatial charge separation. • The AQE for photocatalytic hydrogen production reaches 4.57% at 500 nm, which remains over 50% AQE (8.41%) at 420 nm. • The donor block for carbon nitride allows the electron transfer to the g-C 3 N 4 that keeps the H 2 production site unaltered. Building a donor-acceptor (D–A) type polymeric carbon nitride is a promising way for synthesizing high-performance photocatalysts. Compared with introducing an acceptor unit, incorporating donor blocks can effectively extend the absorption range without altering H 2 production sites. Herein, we report a facile method to construct a d -A structure by introducing the creatinine-derived moiety (CDM) into melem networks via copolymerization of creatinine and urea. CDM units arouse a new absorption band at 500 nm and result in the LUMO and HOMO distribute at melem and CDM unit, which promotes the charge spatial separation. The optimal photocatalytic activity of 9454 μmolg−1 h−1 can be achieved. That does not only improve the apparent quantum yield (AQE) at 420 nm from 3.80 % to 8.41 % but also raises the AQE at 500 nm from 0.71 % to 4.57 %. This strategy provides the potential to extend the further visible light response with a decent performance. [ABSTRACT FROM AUTHOR]