Influence of MoS₂ on Activity and Stability of Carbon Nitride in Photocatalytic Hydrogen Production

• Main Authors: Ramesh P. Sivasankaran, Nils Rockstroh, Carsten R. Kreyenschulte, Stephan Bartling, Henrik Lund, Amitava Acharjya, Henrik Junge, Arne Thomas, Angelika Brückner
• Format: Article
• Language: English
• Published: MDPI AG 2019-08-01
• Series: Catalysts
• Subjects: MoS₂; C₃N₄; composite catalysts; photocatalytic hydrogen production; charge separation and transfer
• Online Access: https://www.mdpi.com/2073-4344/9/8/695

MoS₂/C₃N₄ (MS-CN) composite photocatalysts have been synthesized by three different methods, i.e., in situ-photodeposition, sonochemical, and thermal decomposition. The crystal structure, optical properties, chemical composition, microstructure, and electron transfer properties were investigated by X-ray diffraction, UV-vis diffuse reflectance spectroyscopy, X-ray photoelectron spectroscopy, electron microscopy, photoluminescence, and in situ electron paramagnetic resonance spectroscopy. During photodeposition, the 2H MoS₂ phase was formed upon reduction of [MoS₄]^2− by photogenerated conduction band electrons and then deposited on the surface of CN. A thin crystalline layer of 2H MoS₂ formed an intimate interfacial contact with CN that favors charge separation and enhances the photocatalytic activity. The 2H MS-CN phase showed the highest photocatalytic H₂ evolution rate (2342 μmol h^−1 g^−1, 25 mg catalyst/reaction) under UV-vis light irradiation in the presence of lactic acid as sacrificial reagent and Pt as cocatalyst.