Integration of 2D layered CdS/WO3 S-scheme heterojunctions and metallic Ti3C2 MXene-based Ohmic junctions for effective photocatalytic H2 generation

H2-production and electron-transfer mechanism of a noble-metal-free WO3@ZnIn2S4 S-scheme heterojunction photocatalyst

“…It also features low cost, chemical stability and visible light response. [42][43][44][45] In general, oxide photocatalysts have a higher work function than sulde photocatalysts. [46][47][48] Owing to the work function difference, there would be electron transfer between ZnIn 2 S 4 and WO 3 , thus creating an IEF at their interfaces upon contact.…”

α-NiS–β-NiS growth on Cd0.5Zn0.5S formed Schottky heterojunctions for enhanced photocatalytic hydrogen production

“…8c). 56,57 This result suggests that the E f of NiS is lower than that of Cd 0.5 Zn 0.5 S, inferring that a Schottky junction can be formed after the close contact between Cd 0.5 Zn 0.5 S and NiS. 58 The significant difference between W s (NiS) and W m (Cd 0.5 Zn 0.5 S) reveals the electrons transformation from Cd 0.5 Zn 0.5 S to NiS until setting up an equilibrium state between the E f (NiS) and E f (Cd 0.5 Zn 0.5 S) in NiS/Cd 0.5 Zn 0.5 S. Obviously, the electrons are mainly gathered at the NiS side of the interface, which is accompanied by the loss of electrons at the Cd 0.5 Zn 0.5 S side, further evidencing the redistribution of the electrons at the interface of the heterojunction with the metallic NiS acting as electron acceptors upon contact with Cd 0.5 Zn 0.5 S. 59 The schematic illustration of the overall photocatalytic reaction over NiS is shown in Fig.…”

“…8c). 56,57 This result suggests that the E f of NiS is lower than that of Cd 0.5 Zn 0.5 S, inferring that a Schottky junction can be formed after the close contact between Cd 0.5 Zn 0.5 S and NiS. 58 The significant difference between W s (NiS) and W m (Cd 0.5 Zn 0.5 S) reveals the electrons transformation from Cd 0.5 Zn 0.5 S to NiS until setting up an equilibrium state between the E f (NiS) and E f (Cd 0.5 Zn 0.5 S) in NiS/Cd 0.5 Zn 0.5 S.…”

Solid-state Z-scheme assisted hydrated tungsten trioxide/ZnIn2S4 photocatalyst for efficient photocatalytic H2 production

“…Among them, Z-scheme heterojunction nanocomposites are of particular importance due to their ability to promote not only the charge separation, but also the redox capacity. In a typical Z-scheme heterojunction nanocomposite, due to the well matched band structure of the components, photo-generated electrons and holes with weak redox capacity recombine with each other, leaving the electrons at the more negative conduction band (CB) and the holes at the more positive valence band (VB) separated, which results in long-lived charge separation and improved redox capacity [22][23][24][25][26][27]. Compared with the Z-scheme systems with a shuttle redox mediator, the allsolid-state Z-scheme photocatalytic systems with two semiconductors in direct contact are much more attractive for efficient promotion of the charge separation since they can shorten the electron transfer path and avoid the undesired backward reactions caused by the redox couples [28][29][30][31][32][33].…”