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 (MoS2)/ZnIn2S4 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 ZnIn2S4 and the CNFs‐supported p‐type MoS2 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 MoS2 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 ZnIn2S4 coating for the reduction of H2O into H2, 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 H2 evolution. Consequently, the optimal CNFs/MoS2/ZnIn2S4 composite with 5 mmoL MoS2 loading exhibits robust H2 evolution under simulate sunlight irradiation, achieving a remarkably enhanced photocatalytic H2 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 ZnIn2S4.

Few‐Layered MoxW1−xS2‐Modified CdS Photocatalyst: One‐Step Synthesis with Bifunctional Precursors and Improved H2‐Evolution Activity

“…For the past few years, molybdenum disulfide, a typical layered transition‐metal dichalcogenides (TMDs) with lower cost and higher availability, has been considered as a competitive H 2 ‐evolution cocatalyst with great potential to substitute the precious‐metal cocatalysts. [ 31–33 ] Furthermore, in theory, molybdenum disulfide possesses an outstanding H 2 ‐evolution performance due to its favorable hydrogen‐adsorption Gibbs free energy (Δ G H ) which is comparable with Pt cocatalyst. [ 34–36 ] However, in practice, on account of the insufficient density of edge S active sites and the poor intrinsic electrical conductivity, MoS 2 cocatalyst generally exhibits an unsatisfactory H 2 ‐evolution performance.…”

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

“…The reason is that the BE shift is closely relevant to the chemical valence, chemical circumstances and charge distribution of the elements and the increased BE value resulted from the decrease of electron density. [35][36][37][38][39] Through electron paramagnetic resonance (EPR) tests, the origin of the interaction between the Cd 0.5 Zn 0.5 S and NiS was investigated. 40 Pure Cd 0.5 Zn 0.5 S had a strong signal peak, indicating that there were a lot of S defects on the Cd 0.5 Zn 0.5 S at this time, as shown in Fig.…”

Investigation of the Kinetics and Reaction Mechanism for Photodegradation Tetracycline Antibiotics over Sulfur-Doped Bi2WO6-x/ZnIn2S4 Direct Z-Scheme Heterojunction

“…The flat band potential of negative 0.1 V was considered to be the conduction band edge (E CB ) of n -type semiconductors [ 30 ]. Therefore, the CB potentials of T−ZIS and Sov−BWO were calculated to be −0.81 and −0.51 V (versus Ag/AgCl, PH = 7), which were equal to −0.61 and −0.31 V (versus NHE, PH = 7), respectively [ 43 ]. Meanwhile, the valence band edge (E VB ) of T−ZIS and Sov−BWO were estimated to be 1.80 and 2.51 V versus NHE according to the formula: EVB = ECB + Eg.…”