High-Efficiency Visible Light Responsive Sulfide KSb5S8 Photocatalyst with a Layered Crystal Structure

Abstract

The development of efficient photocatalysts for degrading environmental pollutants in wastewater has drawn considerable attention due to their great potential in industrial applications. Herein, we used a solvothermal method to prepare KSb5S8 with a layered crystal structure. The crystal structure of the as-synthesized samples was characterized by powder X-ray diffraction and transmission electron microscope imaging. Our UV-vis diffuse reflectance spectroscopy results indicated that KSb5S8 could absorb visible light, and its optical band gap was 1.62 eV. The photocatalytic activity of KSb5S8 was evaluated in the degradation of methyl orange. A degradation of 73% within 180 min was achieved under visible light irradiation, which was considerably higher than that of commercial P25 and g-C3N4. Theoretical calculations demonstrated that KSb5S8 was an indirect band gap semiconductor. The estimated effective mass of holes ( m h * ) was approximately two times greater than that of electrons ( m e * ) . The large ratio of m h * / m e * might promote separation of photo-induced carriers during the photocatalytic process. On the basis of the layered crystal structure and large m h * / m e * value, KSb5S8 was a high-performance photocatalyst capable of harvesting visible light. This study provides valuable insight that will aid the design of improved sulfide photocatalytic materials with layered crystal structures.

One-Step Microwave-Assisted Synthesis and Visible-Light Photocatalytic Activity Enhancement of BiOBr/RGO Nanocomposites for Degradation of Methylene Blue

“…The excitation of the electrons (e − ) of the VB into the CB under visible light irradiation leads to the generation of electron–hole pairs. The E CB and E VB of BiOBr were evaluated using the equation below [ 67 ]: E VB = χ − E e + 0.5E g E CB = E V − E g …”

One step to stabilize calcium sodium phosphate crystals acting as photocatalysts embedded in a glass matrix

“…The energy-band potentials of the conduction band and valence band of the CaNaPO 4 glass ceramic are essential to determine the redox ability of the photogenerated species. The band potential of the CaNaPO 4 glass ceramic can be calculated by Equations ( 2)-( 3) [32].…”

Environmental Applications of Photocatalytic Processes

“…The six following publications are focused on the synthesis of new photocatalytic materials. A solvothermal method was used to prepare KSb 5 S 8 with a layered crystal structure and its photocatalytic activity was evaluated in the degradation of methyl orange [3]. The degradation efficiency under visible light irradiation was considerably higher than those obtained with TiO 2 -P25 and g-C 3 N 4 materials, and the promising results will be useful to design improved sulfide photocatalytic materials with layered crystal structures.…”