Composition-Controlled CdS/ZnS Heterostructure Nanocomposites for Efficient Visible Light Photocatalytic Hydrogen Generation

Abstract

To overcome the increasing energy demand worldwide, semiconductor-based photocatalytic H2 production by water splitting has gained much recognition as an alternative approach. However, the main drawbacks are lower visible light absorption and rapid recombination of photogenerated electrons–hole pairs in the semiconductor-based photocatalysts. This work reports the synthesis of CdS/ZnS heterostructures with varied compositions of each component via a single-step solvothermal method and calcination under vacuum. An optimized (CdS)0.4/(ZnS)0.6 composite exhibits the highest photocatalytic H2 generation rate of 830.95 μmol g–1 h–1, which is significantly higher than those of CdS nanorods (254.17 μmol g–1 h–1) and ZnS nanoplates (9.59 μmol g–1 h–1). The higher rate for H2 generation corresponds to better light absorption as well as efficient charge separation in the CdS/ZnS heterostructure. The photoelectrochemical study also confirms the effective charge separation in the CdS/ZnS heterostructure. Based on these results, a probable mechanism is suggested for photocatalytic H2 generation from the CdS/ZnS heterostructure.

Bimetallic MOF-Derived Sulfides with Heterojunction Interfaces Synthesized for Photocatalytic Hydrogen Evolution

“…Similarly, a more positive valence band leads to stronger oxidation ability. Thus, measuring the band position of the photocatalyst is beneficial to the subsequent mechanism analysis and can judge whether the reaction can be theoretically carried out or not Figure S11 shows the XPS valence band spectrum of CdS@NiS, where the inserted subfigure on the upper right indicates a valence band of 1.12 eV.…”

Facile and robust construction of a 3D-hierarchical NaNbO3-nanorod/ZnIn2S4 heterojunction towards ultra-high photocatalytic H2 production

“…6a and b, the pristine NaNbO 3 and ZnIn 2 S 4 both exhibited lower photocatalytic H 2 evolution activity with values of 272.25 μmol h −1 g −1 and 2828.38 μmol h −1 g −1 , respectively, which is attributed to the rapid recombination of photo-generated electron-hole pairs. 57 Nonetheless, all the binary NaNbO 3 / ZnIn 2 S 4 composites with different NaNbO 3 contents displayed visibly superior photocatalytic activity under the same conditions. According to the activity and sacrificial screening, the best NaNbO 3 content in the composites was determined.…”

CdS Nanorods with an Optimized ZnS Coating as Composite Photocatalysts for Enhanced Water Splitting under Solar Light Irradiation

“…21,22 Mixing ZnS with CdS nanoparticles (in a proper ratio) can form a CdS/ZnS heterostructure to degrade methylene blue and enhance the photocatalytic H 2 generation rate. 23,24 ZnS is much more chemically stable than CdS when used in a large pH range. 25 Moreover, due to its wider bandgap (about 3.7 eV), ZnS only suffers from photocorrosion (such as the oxidative degradation) under UV irradiation.…”