CoNi Bimetal Cocatalyst Modifying a Hierarchical ZnIn₂S₄ Nanosheet-Based Microsphere Noble-Metal-Free Photocatalyst for Efficient Visible-Light-Driven Photocatalytic Hydrogen Production

Abstract

Investigating noble-metal-free and earth-abundant cocatalysts has emerged as a promising and challenging issue for improving the photocatalytic hydrogen production efficiency. In this work, a novel CoNi-ZnIn2S4 (CoNi-ZIS) photocatalyst composed of ZnIn2S4 (ZIS) nanosheets (2D) and CoNi bimetal nanosheets (2D) has been designed and fabricated via a simple hydrothermal and chemical reduction process. The detailed characterization results suggest that the introduction of CoNi bimetal is the major driving factor for the improved photocatalytic performance of CoNi-ZIS photocatalyst, which can accelerate the charge migration and inhibit the photoinduced charge carrier (electrons and holes) recombination. The photocatalytic hydrogen production rate of CoNi-ZIS prepared under the optimized condition reaches 100.1 μmol·h–1 irradiated by visible light (λ > 420 nm) in the 0.1 M ascorbic acid (AA), which is approximately 4.3 times higher than that of ZIS. In addition, the potential mechanism over boosted photocatalytic activity was presented according to the characterization results. This study not only develops a specific photocatalyst with an outstanding H2 production property but also provides a favorable inspiration for designing efficient ZnIn2S4-based photocatalyst systems.

Interfacial chemical bond and internal electric field modulated Z-scheme Sv-ZnIn2S4/MoSe2 photocatalyst for efficient hydrogen evolution

“…In the past few years, metal chalcogenide semiconductor photocatalyst, such as ZnS, CdS, PbS, ZnIn 2 S 4 , have absorbed extensively attention due to the favorable visible-light response ability [6][7][8] . ZnIn 2 S 4 is a typical ternary layered metal chalcogenide semiconductor with adjustable band gap of 2.06~2.85 eV, besides, the conduction band is about −1.21 eV, suggesting the intense reducing capacity of the photogenerated electrons 9 . In addition to the suitable band structure, ZnIn 2 S 4 also possess the prominent photo-stability, environmental and human friendliness in comparison to CdS and PbS 10 .…”

A Review and Recent Developments in Full‐Spectrum Photocatalysis using ZnIn2S4‐Based Photocatalysts

“…For instance, Li et al reported a hierarchical ZIS nanosheet‐based microsphere modified by CoNi bimetal cocatalyst. [ 74 ] The flower‐like ZIS microspheres with a size of ≈2 μm are assembled from countless intersecting nanosheets. The results showed that the photocatalytic hydrogen production rate of CoNi–ZIS photocatalyst could reach 100.1 μmol h −1 under visible light irradiation.…”

Interfacial Chemical Bond and Internal Electric Field Modulated Z-Scheme Vs-ZnIn2S4/MoSe2 Photocatalyst for Efficient Hydrogen Evolution

“…Nevertheless, the suitable band structure is insu cient for Z-scheme charge transfer. For example, it is reported that the conduction band potential of MoSe 2 (about -0.45 eV 20 ) is lower than the conduction band of ZnIn 2 S 4 , but very close to its valence band (0.99 eV 21 ), which suggests that the photogenerated electrons on the conduction band of MoSe 2 are likely to recombine with the photogenerated holes on the valence band of ZnIn 2 S 4 following Z-scheme pathway. However, as known from the current literatures, MoSe 2 can only play the role of cocatalyst in ZnIn 2 S 4 /MoSe 2 instead of realizing Z-scheme charge transfer 22,23 .…”

“…S6 shows the wavelength dependent hydrogen evolution e ciency of Vs-ZIS/MoSe 2 , and the corresponding test results and the light power of different monochromatic light are displaying in TableS5. The apparent quantum yield (AQY) of photocatalytic H 2 evolution can be calculated (the detailed calculation process is shown in the The improved light absorption is in favor of the generation of photocarriers, and bene cial for the enhancement of photocatalytic performance21 . Fig.5bis the PL spectroscopy.…”

“…in which C SC represents space charge capacitance, represents the dielectric constant, 0 represents the permittivity of vacuum, e represents the single electron charge, N D represents the charge carrier density, E fb represents the at band potential, k B represents the Boltzmann constant, and T represents the temperature, E represents the electrode potential21 . As displayed in Fig.6b-d, the E fb of ZIS, Vs-ZIS and photoexcited carriers migration between Vs-ZIS and MoSe 2 , thus signi cantly accelerating the Z-scheme charge transfer.…”