Modified Si nanowire/graphite-like carbon nitride core-shell photoanodes for solar water splitting

Si nanowires (SiNWs) and graphite-like carbon nitride (g-C3N4) are highly promising materials for solar water splitting. In this work, n-type SiNWs (n-SiNWs) are obtained via metal-catalyzed electroless etching. To improve the photoelectrochemical performance of the n-SiNWs, g-C3N4 is deposited on their surface as a coating layer (n-SiNW/g-C3N4). Furthermore, to increase the density of active sites in g-C3N4, barbituric acid (BA) is introduced into precursors before the layer deposition. The n-SiNW/g-C3N4 photoanode shows a negative shift of the onset potential as compared to the bare n-SiNWs. Moreover, a 50% enhancement in the photocurrent density at 1.6 V vs. RHE is achieved on the BA-modified n-SiNW/g-C3N4 as compared to the pristine n-SiNW/g-C3N4.