Investigation Of Low-cost Molybdenum Sulfide Catalyst For Hydrogen Production Via Solar Water Splitting

Highly catalytic,cost-effective,well process-compatible,and highly stable hydrogen evolving catalysts are increasingly becoming the key in realizing monolithic electrochemical solar-water-splitting devices.However,typical noble metallic catalysts seriously restrict the industrialization of electrochemical solar-water-splitting devices on account of their poor storage.Low-cost,high-catalytic and non-metallic catalysts pave the promising way for the industrialization process.Molybdenum sulfides have emerged as a type of potential catalyst with high-activity and stability for the hydrogen evolving reaction?HER?in the acidic conditions,nowadays gradually becoming a research hotspot in solar-water-splitting.The process preparation of high-efficient molybdenum sulfide catalysts is consequently extremely important for updating the solar-to-hydrogen efficiency.In thesis,we successfully synthesized amorphous molybdenum trisulfide catalysts at room temperature for hydrogen evolving reaction,followed by extensive studies on the effect of the mass loading of catalysts and molybdenum?Mo?metal supporters on the catalytic activities and the solar-to-hydrogen performance of series solar-water-splitting devices.Firstly,we investigated the material structure and composition of the room-temperature synthesized molybdenum sulfide catalysts.The experimental results illustrated that the molybdenum sulfide synthesized by wet chemical method is amorphous and mainly exists in form of MoS₃.Secondly,we studied the effect of the mass loading of MoS₃ catalysts on material structure and electrical properties and concluded that amorphous molybdenum trisulfide catalysts can achieve the optimized catalytic capacity when the mass loading is 0.5 mg·cm^-2.The overpotential is 260 mV vs.RHE at 10 mA·cm^-22 and Tafel slope is 68 mV·dec^-1,resulting from the rough surface and porous architecture of a-MoS3,which enlarge the electrochemically active area to accelerate the hydrogen evolving reaction.Finally,by dropping the MoS₃ catalysts on sputtered Mo metal supporters to improve the catalytic activities of MoS₃ catalysts,we studied the influence of the thicknesses of Mo supporters.The amorphous molybdenum trisulfide catalysts with a Mo thickness of 500 nm can achieve an optimized catalytic capacity.The overpotential is 210 mV vs.RHE at 10 mA·cm^-22 and Tafel slope is 44.22 mV·dec^-1.concluded that HER catalytic activity can be efficiently enhanced with proposed a-MoS3 catalysts supported by highly conductive Mo supporters,which can enlarge the electrochemically active area and accelerate the charge transfer at catalysts/electrolyte interfaces.