Polymeric Carbon Nitride/Reduced Graphene Oxide/Fe₂O₃: All‐Solid‐State Z‐Scheme System for Photocatalytic Overall Water Splitting

Abstract

The charge transfer between hydrogen evolution photocatalysts (HEPs) and oxygen evolution photocatalysts (OEPs) is the rate‐determining step that controls the overall performance of a Z‐scheme water‐splitting system. Here, we carefully design reduced graphene oxide (RGO) nanosheets for use as solid‐state mediators to accelerate the charge carrier transfer between HEPs (e.g., polymeric carbon nitride (PCN)) and OEPs (e.g., Fe2O3), thus achieving efficient overall water splitting. The important role of RGO could also be further proven in other PCN‐based Z‐systems (BiVO4/RGO/PCN and WO3/RGO/PCN), illustrating the universality of this strategy.

Photocatalyst Z-scheme system composed of a linear conjugated polymer and BiVO4 for overall water splitting under visible light

“…[21][22][23][24] Most photocatalysts so far have been inorganic materials, but organic photocatalysts have attracted growing attention 25 because they can be prepared from earth-abundant elements and their properties-and in particular their light absorption spectrum-can be tuned easily and continuously by co-polymerisation. [26][27][28][29][30][31][32][33][34] However, most polymer studies have been conned to the sacricial half-reaction that produces hydrogen only, and few organic photocatalysts have been developed for overall water splitting. Carbon nitrides have been coupled with WO 3 , which acts as an O 2 evolution photocatalyst in a Z-scheme system for overall water splitting, 26,27,35 but the efficiencies were limited by the commonly observed back reaction.…”

Bilayer MoSe2/HfS2 Nanocomposite as a Potential Visible-Light-Driven Z-Scheme Photocatalyst

“…In particular, great expectations have been placed on the Z-scheme photocatalytic mechanism-which includes two-step excitation and is illuminated by natural photosynthesis in plants [16]-for improving the utilization efficiency of sunlight [17][18][19][20][21][22][23][24]. Generally speaking, the Z-scheme photocatalytic system is made up of three parts: Catalysts for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and the redox mediator for carrier migration [25].…”

Anion-Exchange-Mediated Internal Electric Field: Boosting Photogenerated Carrier Separation and Utilization

“…The average luminescence lifetimes are 3.68 ns for BOH, 3.17 ns for BOH-Cl, 2.63 ns for BOH-Br and 1.96 ns for BOH-I. A shorter PL lifetime indicates that the photo-excitons are more prone to separate rather than to recombine [36][37][38][39] .…”