Synthesis And Photocatalytic Properties Of Carbon-Mediated ZnO Nanorod Arrays

Semiconductor photocatalysis is regarded as an ideal green technology capable of converting solar energy to chemical energy through water splitting,CO₂ reduction and pollutant degradation.As a kind of direct wide bandgap semiconductor material,zinc oxide has many advantages,such as excellent performance,low cost,easy preparation and non-toxicity.Therefore,zinc oxide has been widely studied as an important semiconductor photocatalyst.However,the instability caused by photocorrosion greatly limits the practical application of zinc oxide.How to improve the stability of zinc oxide upon photocatalytic reaction remains a challenge.In this thesis,we report on synthesis of carbon-mediated ZnO nanorod arrays and their photocatalytic properties for CO₂ reduction.ZnO nanorod arrays were prepared by hydrothermal method,through which the bimodal of carbon coating and carbon doping was realized.Different masses of glucose?0.05 g,0.1 g,0.2 g,0.3 g?was used as carbon source.The morphology,structure and optical properties of as-synthesized materials were characterized by TEM,SEM,UV-Vis,Raman,PL,and EIS etc.It was found that the stability of ZnO nanorod arrays mediated by carbon could be greatly enhanced,preventing the photo-corrosion upon photocatalytic reaction.At the same time,the separation and migration of photo-generated electrons and holes were also improved due to the modification of carbon materials.Owing to the synergetic effects mentioned above,the photocatalytic activity of carbon-mediated ZnO nanorod arrays for CO₂ reduction was significantly promoted in comparison with only the ZnO nanorod arrays. Photoelectrochemical result showed that the photocurrent of carbon-mediated ZnO nanorod arrays was 4.4 times higher than that of ZnO nanorod arrays only.It has been confirmed that carbon mediation is a viable method for enhancing the photocatalytic stability and activity.Related mechanism was proposed accordingly.