The cracking of water into hydrogen using solar energy under the action of semiconductor photocatalyst is a green and sustainable technology,which is beneficial to solving the energy crisis and environmental problems.Among various photocatalysts,zinc indium sulfide(ZnIn2S4)has received wide attention from researchers due to its suitable band gap,versatile morphology,and stable performance.However,the defects such as low photogenerated carrier migration efficiency,poor adsorption,and few active centers also limit its application in photocatalysis.To effectively solve these problems,this thesis investigates the modification of two-dimensional ZnIn2S4-based photocatalytic materials from the following two aspects,and provides an in-depth analysis of the nature of their enhanced performance as follows:(1)Two-dimensional ultrathin Ti3C2/Svac-ZnIn2S4 photocatalysts with abundant sulfur vacancies were synthesized by a one-step hydrothermal method.The synergistic effect of sulfur vacancies and Ti3C2 MXene in the Ti3C2/Svac-ZnIn2S4 system greatly improves the light absorption,carrier separation,and adsorption and activation of water molecules,which leads to a significant improvement of the photocatalytic hydrogen production performance.Among them,the hydrogen production rate of Ti3C2/Svac-ZnIn2S4 is 1.44mmol·g-1·h-1,9.5 times and 6.3 times higher than that of ZnIn2S4(151.85μmol·h-1·g-1)and Svac-ZnIn2S4(229.16μmol·h-1·g-1),respectively.The formation of two-dimensional ultrathin Ti3C2/Svac-ZnIn2S4 is confirmed by SEM,TEM,AFM,and other structural characterization.The photoelectrochemical properties characterization confirmed the excellent carrier separation efficiency and enhanced optical absorption properties of Ti3C2/Svac-ZnIn2S4.In addition,theoretical calculations partially demonstrated that the introduction of Ti3C2 MXene and S vacancies synergistically improved the adsorption and activation of water molecules and promoted the catalytic reaction.(2)RuS2 quantum dots(RuS2 QDs)were synthesized by a simple bottom-up method and loaded on the surface of two-dimensional Ti3C2/ZnIn2S4 nanosheets to form RuS2QDs/Ti3C2/ZnIn2S4 ternary composites.Due to the strong conductivity of Ti3C2 and the platinum-like properties of RuS2,the carrier utilization of the ternary system RuS2QDs/Ti3C2/ZnIn2S4 is greatly enhanced and its photocatalytic hydrogen production performance is further enhanced.We also prepared RuS2 QDs/ZnIn2S4 and Ti3C2/ZnIn2S4nanosheets using the same experimental method.The results showed that RuS2QDs/Ti3C2/ZnIn2S4 had the strongest activity of photocatalytic hydrogen production(1.91mmol·h-1·g-1),which was 9.8 times of that of ZnIn2S4(195.51μmol·h-1·g-1).The hydrogen production rate of RuS2 QDs/ZnIn2S4(1.03 mmol·h-1·g-1)and Ti3C2/ZnIn2S4(1.44 mmol·h-1·g-1)was 5.3 times and 7.3 times than that of ZnIn2S4,respectively.Therefore,the synergistic effect of RuS2 QDs and Ti3C2 MXene makes ZnIn2S4 produce more electron-hole pairs and accelerate the transfer to the catalyst surface for the reduction reaction,thus improving the photocatalytic hydrogen production performance of ZnIn2S4. |