Enhancement of Interfacial Charge Transportation Through Construction of 2D–2D p–n Heterojunctions in Hierarchical 3D CNFs/MoS₂/ZnIn₂S₄ Composites to Enable High‐Efficiency Photocatalytic Hydrogen Evolution

Abstract

Hierarchical three‐dimensional (3D) carbon nanofibers (CNFs)/molybdenum disulfide (MoS 2 )/ZnIn 2 S 4 composites with p–n heterojunctions between the basal planes of two‐dimensional (2D) phases are fabricated, using in situ spinning‐based chemical vapor deposition together with hydrothermal processing. It is found that large and intimately interfaced 2D–2D planes between the n‐type ZnIn 2 S 4 and the CNFs‐supported p‐type MoS 2 enable evident junction rectification effect, which facilitates interfacial charge separation to assist effective suppression of the recombination of photogenerated electrons and holes. In addition, the p‐type MoS 2 nanosheets with high in‐plane conductivity and narrower bandgap are highly effective in providing larger quantities of photoinduced electrons, which can be readily injected into the outer n‐type ZnIn 2 S 4 coating for the reduction of H 2 O into H 2 , whereas the holes are driven into the CNF cores by the junction field to be finally scavenged. The large specific surficial area of the sulfides provides abundant sulfur‐rich sites active for H 2 evolution. Consequently, the optimal CNFs/MoS 2 /ZnIn 2 S 4 composite with 5 mmoL MoS 2 loading exhibits robust H 2 evolution under simulate sunlight irradiation, achieving a remarkably enhanced photocatalytic H 2 production rate over 151.42 mmoL⋅h −1 ⋅g −1 and a high apparent quantum yield of 20.88% at 365 nm, which is 4.65 times higher than that of pristine ZnIn 2 S 4 .