Photoelectrochemical Properties Of Carbon Nitride Modified Metal Oxide Nanowire Arrays

Photoelectrochemical?PEC?cells decompose water is an important way to use solar energy efficientcy.The efficiency and stability of photoanodes are the key factors for PEC cells to decompose water.Metal oxide nanowire arrays are considered as ideal photoanode materials for PEC cells due to their good chemical stability and high photohydrogen efficiency.Most metal oxides have large band gap energy,which results in limited light absorption in the visible light region,which fundamentally limits the efficiency of photohydrogen production.Carbon nitride?C₃N₄?has good absorption in the visible light region,high catalytic activity and good chemical stability.I believe that C₃N₄ modification is an effective way to improve the absorption of metal oxides in the visible region.C₃N₄,zinc oxide?ZnO?nanowire arrays and titanium dioxide?TiO₂?nanowire arrays were synthesized.Metal oxide nanowire arrays were modified with C₃N₄ to make photoanode devices,and photoanode materials with well photoelectrochemical properties were obtained.The research work are as follows:1.Graphite carbon nitride?g-C₃N₄?and amorphous carbon nitride?a-C₃N₄?were synthesized by using dicyandiamine as precursor.Structural characterization and visible light absorption range of the two samples were experimented.The results showed that the structures of two samples were the same,a-C₃N₄ had a wider light absorption range in the visible region than g-C₃N₄.2.ZnO nanowire arrays were synthesized by hydrothermal method.The ZnO nanowire arrays were modified with g-C₃N₄ and a-C₃N₄.The morphology and structure of g-C₃N₄/ZnO and a-C₃N₄/ZnO were characterized.The results showed that the modification of g-C₃N₄ and g-C₃N₄ will not change the structure of nanowire array.A-C₃N₄/ZnO has a wider light absorption range in the visible region than g-C₃N₄/ZnO.Photoelectrochemical experiments showed that a-C₃N₄/ZnO has better photoelectrochemical performance than g-C₃N₄/ZnO.3.TiO₂ nanowire arrays were synthesized by hydrothermal method.The g-C₃N₄and a-C₃N₄ modified TiO₂ nanowire arrays were used to characterize the morphology and structure of g-C₃N₄/TiO₂ and a-C₃N₄/TiO₂.The results showed that the modification of g-C₃N₄ and a-C₃N₄ will not change the structure of the nanowire array.A-C₃N₄/TiO₂ has a wider light absorption range in the visible region than g-C₃N₄/TiO₂.Photoelectrochemical experiments shoed that a-C₃N₄/TiO₂ has better photoelectrochemical performance than g-C₃N₄/TiO₂.