Preparation And Photocatalytic Hydrogen Production By Water Splitting Of Molybdenum Disulfide And Its Composites

More and more attention has been paid to the conversion of solar energy into hydrogen due to its clean, low cost and environmentally friendly features. However, to achieve the application of solar-driven photocatalytic hydrogen production by water splitting, two key issues must be solved. The first one is the development of cost-efficient and stable visible light active photocatalysts, the other is to construct an efficient and stable hydrogen production system. In recent years,molybdenum disulfide(Mo S2) with two-dimensional layer structure has attracted more and more attention due to its unique properties and provides a new way for hydrogen production. In this paper, molybdenum disulfide and its composites have been prepared and their photocatalytic hydrogen production performances were investigated in details.(1) Molybdenum disulfide with high hydrogen-evolving activity was successfully synthesized by using Na2 Mo O4·2H2O as molybdenum source, KSCN as sulfur source and reducing agent, DMF as solvent and its composition, morphology and microstructure were characterized in details. A maximum hydrogen production rate of 876 μmol·h-1 was achieved by using Eosin Y(EY2-) as sensitizer, triethanolamine(TEOA) as electron donor under the optimal conditions. Moreover, the H2-evolving activity of Mo S2 was nearly unchanged after four cycles.(2) 4-MBA@Mo S2 composites were synthesized by a refluxing method and the results show that the the loading of 4-MBA not only enhanced the absorption ability of Mo S2 in the visible region, but also increased its hydrogen production performance. When the loading amount of 4-MBA was 1.5 wt%, the rate of hydrogen production reached 1849.6 μmol·h-1, about 2.1 times higher than that of Mo S2(876 μmol·h-1).(3) Mo S2/Ti O2 nanocomposites were synthesized by one-step solvothermal method and an efficient and noble-mental-free photocatalytic hydrogen production system was constructed with Mo S2 as cocatalyst, EY2- as sensitizer and TEOA as electron donor. The factors affecting its H2-evolving performance were investigated in details and a hydrogen production rate of 141.1 μmol·h-1 was achieved under the optimal conditions, which is about 21 times higher than that of pure Ti O2 under the same conditions. A cycle experiment was done to study the stability of the Mo S2/Ti O2 nanocomposite and the hydrogen production system,and the deactivation reasons were investigated primarily.