Non-precious Metal Phosphide Modified The Ternary Chalcogenide And The Study On Photocatalytic Performance Of Hydrogen Production

The consumption of non-renewable resources such as coal,oil and natural gas leads to more and more serious environment pollution problems.Thus the development of clean and renewable energy becomes more imminent.Photocatalytic hydrogen evolution has been considered to be one of the effective ways that utilize solar energy to solve fossil energy shortage and environmental pollution problems.However,the photocatalytic hydrogen evolution reaction is complicated,the photocatalyst and co-catalyst are two key factor affecting the photocatalytic efficiency.The introduction of co-catalyst can effectively promote the hydrogen evolution rate during the photocatalytic process,thus,the development of cheap and efficient co-catalyst has become one of the research focus.In this paper,In this paper,combining with the photocatalytic hydrogen evolution reaction mechanism,several mian host photocatalysts and co-catalysts in the photocatalytic systems are introduced.The types and research contents of co-catalysts on photocatalytic hydrogen evolution reaction are summarized.The characteristics and mechanism of several types of photocatalysts and co-catalyst are also analyzed.In the research part,we first prepared the higher stability of the ternary sulfide CaIn₂S₄,the analogous metal Ni₂P as the cocatalyst,and prepared the Ni₂P/CaIn₂S₄ composite.The result shows that Ni₂P can effectively increase the photocatalytic hydrogen production activity of CaIn₂S₄.When the loading reaches 10%,Ni₂P has the best hydrogen production activity and its activity is even higher than that of Pt modified CaIn₂S₄.Characterization results show that Ni₂P has a certain kind of metallicity,and its modification of CaIn₂S₄ can form metalloid-semiconductor heterojunction.In the photocatalytic hydrogen production,because of the analogous metallic nature of Ni₂P,the photogenerated electron transfer on the surface of CaIn₂S₄ is promoted,and the good reduction ability of Ni₂P promotes the photo-induced electron consumption.Therefore,the photocatalytic hydrogen performance of Ni₂P/CaIn₂S₄ composite has been significantly improved.The morphology and surface state of co-catalyst will directly affect its electrocatalytic hydrogen production over-potential.It is similar to the photocatalytic process,co-catalyst morphology,structure,surface state will also affect its photo-generated carrier separation and transmission.Therefore,Ni₂P nanomaterials with different morphologies were prepared in this paper,and the effect of the morphology of the materials on the electrocatalytic hydrogen evolution performance in acidic solution was studied.The results show that Ni₂P nanomaterials with ultrathin sheet-like structure exhibit higher catalytic activity with excellent stability.Based on the above research,in the last part of the dissertation,Ni₂P with ultrathin sheet-like structure was selected as co-catalyst,ZnIn₂S₄ with the same ultra-thin sheet structure was also chosen as the host photocatalyst.As a result,Ni₂P/ZnIn₂S₄ composite was prepared and the effect of Ni₂P morphology on the photocatalytic hydrogen evolution activity was studied.The results show that the 2D-2D Ni₂P/ZnIn₂S₄ composite has higher photocarrier separation efficiency and hydrogen production efficiency than the 0D-2D Ni₂P/ZnIn₂S₄ composite.Among them,the quantum efficiency of 10%2D-2D Ni₂P/ZnIn₂S₄composite photocatalyst reached as high as 7.7%at 420±20 nm.This is mainly due to the modification of the two-dimensional cocatalyst which can effectively increase the electron transport area of the photocatalyst and the cocatalyst,so that the photocatalytic activity of the composite material is more effectively enhanced.