Synergistic Effect of the Surface Vacancy Defects for Promoting Photocatalytic Stability and Activity of ZnS Nanoparticles

Abstract

High activity, high stability, and low cost have always been the pursuit of photocatalyst design and development. Herein, a simple method is used to integrate abundant anion vacancies (VS) and cation vacancies (VZn) on the surface of ZnS (M–ZnS), deriving VS and VZn pairs (vacancy pairs), isolated Zn atoms (Zniso), and isolated S atoms (Siso). Abundant surface vacancy defects fully expose and activate the surface atoms, regulate the band structure, and significantly improve the separation of photogenerated carriers. M–ZnS is endowed with high activity, and the average hydrogen production rate of the optimal sample increases to 576.07 μmol·g–1·h–1 (λ > 400 nm). Theoretical simulations indicate that the activated Zn atoms are the dominant active sites via the formation of a Zn–OH bond with H2O. Especially, the strong interactions of electrons in atomic orbitals at vacancy pairs and the introduction of VZn are conducive to high stability. The optimal sample maintains an average hydrogen production rate of 6.59 mmol·g–1·h–1 (300 W Xe lamp) after nine cycles. Hence, this work deepens the understanding of vacancy defects and provides an idea for the design of a stable photocatalyst.

Amorphous WP‐Modified Hierarchical ZnIn2S4 Nanoflowers with Boosting Interfacial Charge Separation for Photocatalytic H2 Evolution

“…[28] The EPR spectra were carried out to further investigate the existence of Zn and S vacancies. [67] The ZnIn 2 S 4 sample shows the sharply increased EPR signal at a g-factor of 2.009, confirming the abundant S-vacancies in ZnIn 2 S 4 (Figure 9c). In addition, it is also can observed that the EPR intensity of Zn vacancies exhibits a slightly increased signal.…”

Cu Vacancy Induced Product Switching from Formate to CO for CO2 Reduction on Copper Sulfide

“…As for SNC@Cu 2 S, the HR-TEM image shows an interplanar spacing of 0.19 nm (Figure S3c), which is ascribed to the (220) crystal planes of Cu 2 S. Another interesting feature from the HR-TEM image of SNC@Cu 1.96 S is the lattice defect marked with a red square (Figure c), and the amplified image is shown in Figure S4. Compared with SNC@Cu 2 S, SNC@Cu 1.96 S have more obscure and discontinuous lattice fringes, implying the existence of abundant defects. − Such remarkable lattice defects are prevalent in the Cu 1.96 S shell as shown in Figure S5.…”

Metal Sulfides for Photocatalytic Hydrogen Production: Current Development and Future Challenges

“…With only a small amount of Ni single atoms (0.0013 wt%), the photocatalytic hydrogen evolution of Ni-NG/CdS composites was obviously improved. [90] Copyright 2021, American Chemical Society.…”

“…Recently, it has been found that vacancy clusters formed in some metal sulfides. [90][91][92] For example, vacancy pairs (sulfur and zinc vacancy) were successfully integrated on the surface of ZnS by a simple "occlusional coprecipitation" method. [90] Atomic structure characterizations suggested that sulfur and zinc vacancy pairs were clearly observed on the surface of ZnS, as shown in Figure 6a.…”

“…[90][91][92] For example, vacancy pairs (sulfur and zinc vacancy) were successfully integrated on the surface of ZnS by a simple "occlusional coprecipitation" method. [90] Atomic structure characterizations suggested that sulfur and zinc vacancy pairs were clearly observed on the surface of ZnS, as shown in Figure 6a. The vacancy clusters in ZnS not only induced defect energy levels to enable visible light absorption but also captured electrons to improve the charge separation.…”