An Interface Optimization Strategy for g-C₃N₄-Based S-Scheme Heterojunction Photocatalysts

Abstract

Graphitic carbon nitride (CN) has attracted much attention in photocatalytic fields due to its unique electronic band structure. However, the rapid recombination of photogenerated carriers severely inhibits its catalytic activity. The heterojunction structure has been widely confirmed to significantly improve the photocatalytic activity of CN through the formed interface structure. However, researchers often give attention to the band matching and conductivity of the cocatalyst, while the importance of the interface as a migration channel for photogenerated carriers is often overlooked. In this work, we adopt the strategy of morphology engineering to regulate the morphology of the CN photoactive component so as to achieve the interface optimization of the traditional heterojunction structure. The photocatalytic degradation experiment of rhodamine B shows that compared with the traditional CeO2@CN heterojunction structure, the photocatalytic activity of the interface-optimized CeO2/CN is increased by more than 20%. The following points could be used to explain the improvement of photocatalytic activity: (I) the formed S-scheme heterojunction structure, which inhibits the recombination of useful electrons and holes but expedites the recombination of relatively useless electrons and holes, (II) the increased interface area, which provides more carrier migration channels, and (III) the reduced interface contact resistance, which facilitates the separation and migration of photogenerated carriers. Furthermore, the interface optimization of the traditional Al2O3@CN and Fe2O3@CN heterojunction structures also achieved consistent results. This shows that the strategy in this work is a universal method for interface optimization, which provides potential alternative for further improving the catalytic activity of other heterojunction composites.

Acceleration of Photocatalytic CO2 Reduction at Intimate Interface in AgBr/BiOBr Heterojunctions via a Co-anion Strategy

“…Nitrogen (N 2 ) physisorption desorption tests were performed on pure BiOBr and 1.0 AgBr/BiOBr, as shown in Figure d. Both of them have type IV hysteresis loops, indicating the presence of mesoporous structures . An abundant pore structure is conducive to the refraction of light during the photocatalytic process.…”

2D material based heterostructures for solar light driven photocatalytic H2production

“…Moreover, the interfacial contact can also be moderated to reduce interface contact resistance and facilitate charge migration and separation. 154 3.2.4 Other heterostructures. When n-type CN is in contact with a p-type semiconductor, the electrons will transfer from CN to the p-type semiconductor, resulting in an upward band bending of CN and a downward band bending of the p-type counterpart.…”

“…Moreover, the interfacial contact can also be moderated to reduce interface contact resistance and facilitate charge migration and separation. 154…”

Enhancing Green Product Generation of Photocatalytic NO Oxidation: A Case of WO3 Nanoplate/g-C3N4 S-Scheme Heterojunction

“…Thanks to the above interesting properties, the WO 3 /g-C 3 N 4 heterostructure was used as a direct solid-state Z-scheme heterojunction that is coupled by two suitable semiconductors to decompose sulfamethoxazole, methylene blue, and 4-chlorophenol in wastewater under visible light. , Recently, Fu et al reported that the coupling of WO 3 /g-C 3 N 4 created an efficient step-scheme (S-scheme) structure photocatalyst favorable for visible-light-driven hydrogen production . The S-scheme has more advantages compared to the Z-scheme, which directs the transfer of charge carriers at the heterojunctions of the two-component semiconductors via the internal electric field direction, the bending band edge, and the Coulomb force interaction. − Literature studies indicate that the energy band structure of WO 3 is suitable to establish a Z-scheme photocatalyst with g-C 3 N 4 . , This heterojunction will inhibit the electron–hole recombination rate, leading to the formation of active radicals to prevent the conversion of NO to NO 2 for the WO 3 /g-C 3 N 4 system.…”