| As the two major problems of the energy crisis and environmental pollution become increasingly prominent,finding a new,efficient and clean energy resource is an urgent problem in today’s society.Hydrogen has been considered as the most promising alternative energy due to its pollution-free,high combustion value and combustion cleanliness.Photocatalytic water splitting hydrogen production technology is regarded as an ideal,clean and efficient hydrogen production method.Therefore,to explore and develop efficient and stable photocatalytic materials with visible light response has become the emphasis and difficulty in the field of photocatalysis research.Studies have shown that 2D/2D heterojunction composites can not only facilitate the separation and transmission of photogenerated carriers,but also provide sufficient reactive sites,thereby enhancing the photocatalytic reaction activity.Herein,we have constructed three 2D/2D cocatalyst/CdS heterojunction catalysts and investigated their photocatalytic H2 evolution performance.The main contents are overviewed as follows:1.Firstly,2D ultrathin CdS and Mo S2 nanosheets were prepared via ultrasonic stripping method,and then 2D/2D Mo S2/CdS heterojunction composites were synthesized by calcination in an inert atmosphere.The photocatalytic H2 production performance of the as-synthesized samples were measured under visible light（λ>420 nm）irradiation using lactic acid as a sacrificial reagent.And the results demonstrated that the 7wt%2D/2D Mo S2/CdS revealed the hightest photocatalytic H2 evolution rate of 18.43mmol·h-1·g-1 and the apparent quantum efficiency（AQE）of 34%under 420nm monochromatic light.2.Combining the 2D Ni2P nanosheets obtained by high-temperature phosphating with ultrathin CdS nanosheets exfoliated in liquid phase to construct the 2D/2D Ni2P/CdS heterojunction composites via adsorption-calcination method.The photocatalytic H2 evolution rate of 2D/2D Ni2P/CdS composites were measured under visible light irradiation with lactic acid as a sacrificial reagent.And the highest H2 evolution rate was 17.95mmol·h-1·g-1,while the corresponding apparent quantum efficiency（AQE）was 4.2%（420 nm）.3.2D/2D CoP/CdS heterojunction composites were fabricated via combining the 2D CoP nanosheets obtained by high-temperature phosphating with ultrathin CdS nanosheets.Then the effect of CoP content on photocatalytic performance was compared under visible light irradiation,and the results indicated that the highest H2 production rate of 7wt%2D/2D CoP/CdS reached 92.5 mmol·h-1·g-1with lactic acid as the sacrificial reagent.Meanwhile,the AQE measured under the same conditions was 14.8%（420nm）.In this paper,2D ultrathin CdS is selected as a catalyst,and 2D/2D heterojunction photocatalysts were prepared via compounding with typical 2D cocatalysts to improve the photocatalytic performance.The effects of loading capacity and the type of sacrificial reagent on the photocatalytic performance of composite materials were explored,and finally a possible mechanism was proposed. |
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