Photocatalytic Hydrogen Production Performance Of AgNWs-Based Composites Enhanced By Surface Plasmon Resonance

With increasing energy demand and decreasing non-renewable energy sources due to industrialization,the conversion of solar energy into hydrogen energy using semi-conductor photocatalysts is considered to be a feasible way to meet the global demand for clean and sustainable energy.In order to solve the problems of low light utilization efficiency and low carrier separation efficiency of semiconductor photocatalysts,it has been proposed to combine metal nanoparticles and semiconductors to construct surface plasmon photocatalysts.The LSPR effect of metal nanoparticles can generate a local electric field in the adjacent interface with the semiconductor,which can improve the separation efficiency of semiconductor electrons and holes,thereby improving the photocatalytic activity of the semiconductor.Changing the surface curvature of metal particles can adjust the local electric field strength（tip effect）.People have synthesized metal particles with different curvatures（such as spherical,cubic or triangular,etc.）and carried out preliminary research in the field of photocatalysis.However,the above studies cannot evaluate the degree of influence of factors such as crystallinity and composition of nanoparticles on the performance.Few reports have given direct experimental evidence on the effect of surface electric field strength on photocatalytic activity.This paper proposes that directly modifying the surface structure of metal ions can effectively exclude the effects of crystallinity and composition.This paper is the first to apply silver nanowire-based composites with different surface curvature structures in the field of photocatalysis.Through experimental verification and calculation simulation,it is directly proved that the tip effect improves the performance of photocatalytic hydrogen production.First,silver nanowires with smooth and rough surfaces were constructed by selective etching,and then AgNWs@Zn_0.5Cd_0.5S and AgNWs@Ti O₂composites were synthesized by sol-gel and solvothermal methods,and the composition was system-atically studied content,surface curvature and other factors affecting the photocatalytic hydrogen production performance,the mechanism of the improvement of photocatalytic hydrogen production performance was studied in detail by means of theory and experiment,the specific content is as follows:（1）In view of the problems of low photogenerated carrier separation efficiency and low spectrum utilization range in the process of photocatalytic water splitting hydrogen production in traditional single semiconductors,this paper proposes to introduce an etched AgNWs cocatalyst with a high curvature surface,using a AgNWs@Zn_0.5Cd_0.5S photocatalyst for hydrogen production was synthesized by a sol-gel method.In this work,etched AgNWs with high curvature on the surface were obtained by etching AgNWs to roughen the surface without destroying the structure and composition of AgNWs.These results show that etching AgNWs@Zn_0.5Cd_0.5S enhances the local electric-field strength in its LSPR effect due to the tip effect,thereby helping itself to separate and transfer hot electrons and helping Zn_0.5Cd_0.5S to excite electron-hole separation,enhancing the Pho-tocatalysis can improve the photocatalytic hydrogen evolution activity of Zn_0.5Cd_0.5S.（2）In order to verify that etched AgNWs with high curvature can also help other semiconductors to improve the photocatalytic hydrogen production performance,Ti O₂se-miconductor photocatalyst and AgNWs were selected in this experiment,and a series of AgNWs@Ti O₂were prepared by solvothermal method.The experimental results show that the introduction of two kinds of AgNWs makes Ti O₂obtain better photocatalytic activity.Among them,the main role of the local electric field of AgNWs is to help Ti O₂generate more electrons,while the thermal electron injection mechanism only plays a small role,which more effectively helps the photocatalytic hydrogen evolution performance of Ti O₂.Moreover,the results show that the enhanced local electric field of AgNWs with high curvature surface can better assist the photocatalytic hydrogen production from TiO₂.