Structure鈥揂ctivity Relationships in Bulk Polymeric and Sol鈥揋el-Derived Carbon Nitrides during Photocatalytic Hydrogen Production

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• 作者：Dirk Hollmann ; Michael Karnahl ; Stefanie Tschierlei ; Kamalakannan Kailasam ; Matthias Schneider ; J枚rg Radnik ; Kathleen Grabow ; Ursula Bentrup ; Henrik Junge ; Matthias Beller ; Stefan Lochbrunner ; Arne Thomas ; Angelika Br眉ckner
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：February 25, 2014
• 年：2014
• 卷：26
• 期：4
• 页码：1727-1733
• 全文大小：353K
• 年卷期：v.26,no.4(February 25, 2014)
• ISSN：1520-5002

文摘

Photocatalytic hydrogen evolution rates and structural properties as well as charge separation, electron transfer, and stabilization have been analyzed in advanced sol鈥揼el-derived carbon nitrides (SG-CN) pyrolyzed at different temperatures (350鈥?00 掳C) and in bulk polymeric carbon nitride reference samples (CN) by XRD, XPS, FTIR, UV鈥搗is, Raman, and photoluminescence as well as by in situ EPR spectroscopy. SG-CN samples show about 20 times higher H₂ production rates than bulk CN. This is due to their porous structure, partial disorder, and high surface area which favor short travel distances and fast trapping of separated electrons on the surface where they are available for reaction with protons. In contrast, most of the excited electrons in bulk polymeric CN return quickly to the valence band upon undesired emission of light, which is responsible for their low catalytic activity.