Hydrothermal synthesis of a two‐dimensional g‐C₃N₄/MoS₂/MnOOH composite material and its potential application as photocatalyst

Abstract

BACKGROUND: Environmental pollution and energy crisis are nowadays considered among the most important problems facing humanity. Several strategies have been proposed to solve them, being photocatalysis a very promising one because of its ease of application and low cost. In the search for active photocatalysts, those based on graphite-like carbon nitride (g-C 3 N 4 ) are becoming good alternatives for various reactions. In this work, the properties of g-C 3 N 4 /MoS 2 /MnOOH composite material and its photocatalytic behavior for the production of hydrogen (H 2 ) under UV radiation were investigated. RESULTS:The composite material was synthesized by applying a combination of thermal condensation and hydrothermal methods. According to the results of X-ray diffraction (XRD), ultraviolet diffuse reflectance spectroscopy (UV-DRS), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM), good dispersion of the phases and the formation of a heterojunction were observed. The band gap value of the composite material, calculated by the Kubelka-Munk equation using the values obtained from UV-DRS analysis, was lower than those of the individual components, while it also had a much longer electron-hole recombination time, according to photoluminescence analysis. As a consequence of a synergistic effect, the activity of the proposed composite photocatalyst was superior in the reaction of water splitting, with a kinetic constant of 466 mol h −1 and a production rate of 1750 mol H 2 g −1 cat h −1 (50 and 21% higher than those obtained with MoS 2 and g-C 3 N 4 , respectively). CONCLUSION: Because of its high activity and stability, g-C 3 N 4 /MoS 2 /MnOOH composite photocatalyst is an excellent alternative for H 2 production by the water splitting reaction. REFERENCES1 Sun H and Wang S, Research advances in the synthesis of nanocarbon-based photocatalysts and their applications for photocatalytic conversion of carbon dioxide to hydrocarbon fuels. Energy Fuels 28:22-36 (2014).

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