Carbon-Doped Carbon Nitride Nanosheets as Visible-Light Driven Photocatalysts for Hydrogen Generation from Water Decomposition

• Main Authors: Po-KaiChuang, 莊博凱
• Other Authors: Hsisheng Teng
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/56180053188241392117

碩士 === 國立成功大學 === 化學工程學系 === 104 === This study details the synthesis of high-activity g-C3N4 catalysts for H2 generation from a triethanolamine aqueous solution under visible light. We anneal a mixture of urea and NH4Cl to obtain g-C3N4 nanosheets, which are subsequently solvated with ethanol molecules and annealed to form aromatic carbon-doped g-C3N4. The results of analyses conducted using X-ray photoelectron, Fourier-transform infrared, and 13carbon-13 nuclear magnetic resonance spectroscopies demonstrated that annealing the ethanol molecules leads to the grafting of aromatic heterocycles on the g-C3N4 nanosheets. The results of photoluminescence and electron paramagnetic resonance measurements reveal that the grafted aromatic heterocycles extend the π-conjugation system in g-C3N4 to reduce the band gap and facilitate the separation of photogenerated charges. The grafted aromatic heterocycles also preserve the crystallinity of g-C3N4 during high-temperature annealing, which facilitates the suppression of the recombination of photogenerated charges at defect sites. The developed aromatic carbon-doped g-C3N4 effectively catalyzes H2 generation from water decomposition, achieving apparent quantum yields of 14% and 2.2% under 420- and 550-nm monochromatic irradiation, respectively, whereas urea-derived g-C3N4 reached only 3.4% and 0.1%. The proposed strategy of extending the π-conjugation system is promising for promoting the activity of carbon-nitride photocatalysts.