Collaborative enhancement of photon harvesting and charge carrier dynamics in carbon nitride photoelectrode

Target-oriented photoelectrochemical (PEC) performance can be enabled by regulating the physicochemical properties of graphitic carbon nitride (CN)-based photoanodes in the PEC process. Herein, we introduced boron heteroatoms into CN films (BCN) and explored the influence of the B heteroatom on the PEC performance experimentally and theoretically. B atoms favor substitution of carbon atoms at bay sites in BCN films and reduce the bandgap by raising the valence band edge as well as constructing optimal electronic structures for PEC hydrogen production. The as-prepared BCN films exhibit nearly 4 times higher photocurrent density than that of pristine CN films. We demonstrate that such enhancement originates from the spatially complementary orbital distribution over the BCN films, thus expediting the charge carrier separation. This work proposes ideal empirical routines for multiple functionalization of CN films for diverse PEC activities via component tailored strategies.