Facile fabrication of α-Fe₂O₃/Ag₂S heterojunction with enhanced photoelectrochemical water splitting property

The α-Fe₂O₃/Ag₂S p-n heterojunction has been prepared via a facile room temperature successive ionic layer adsorption and reaction (SILAR) method. The heterojunction exhibits higher photoelectrochemical property compared to bare α-Fe₂O₃. The amount of Ag₂S has a significant effect on the PEC performance, which could be controlled by varying the number of SILAR cycles. The α-Fe₂O₃/Ag₂S p-n heterojunction prepared via 6 cycles of SILAR processes displays the best photoelectrochemical performance, which exhibits 1.8 times enhancement of photocurrent density and 70 mV cathodic shift of onset potential compared to bare α-Fe₂O₃. The improved PEC performance could be attributed to the formation of p-n junction between Ag₂S and α-Fe₂O₃, which not only enhanced the optical absorption ability, but also facilitated the separation efficiency of photogenerated charge carriers and passivized the surface state.