Carbon Nitride-Aromatic Diimide-Graphene Nanohybrids: Metal-Free Photocatalysts for Solar-to-Hydrogen Peroxide Energy Conversion with 0.2% Efficiency
Carbon Nitride-Aromatic Diimide-Graphene Nanohybrids: Metal-Free Photocatalysts for Solar-to-Hydrogen Peroxide Energy Conversion with 0.2% Efficiency
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DOI：
10.1021/jacs.6b05806
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发表时间：
2016-08-10
影响因子：
15
通讯作者：
Hirai, Takayuki
中科院分区：
文献类型：
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作者：
Kofuji, Yusuke;Isobe, Yuki;Hirai, Takayuki
太阳能-化学能转换是可再生能源储存的一个具有挑战性的课题。在过去的40年里，人们对半导体光催化将整体水分解为H2和O2进行了广泛的研究;然而，它们需要贵金属并极其小心，以避免混合气体爆炸。在这里，我们报道了有机半导体光催化剂从水和O-2中产生过氧化氢（H2 O2），可以为无金属和爆炸风险的清洁能源储存提供新的基础。我们发现通过简单的水热煅烧过程制备的氮化碳芳香二酰亚胺石墨烯纳米杂化物在可见光（λ> 420 nm）下由纯水和O-2产生H2 O2。半导体氮化碳芳族二酰亚胺部分的光激发将其导带电子转移到石墨烯并增强电荷分离。半导体部分上的价带空穴氧化水，而石墨烯部分上的电子促进O-2的选择性双电子还原。这种不含金属的系统产生的H2 O2的太阳能-化学能转换效率为0.20%，与粉末状水分解光催化剂所达到的最高水平相当。
Solar-to-chemical energy conversion is a challenging subject for renewable energy storage. In the past 40 years, overall water splitting into H-2 and O-2 by semiconductor photocatalysis has been studied extensively; however, they need noble metals and extreme care to avoid explosion of the mixed gases. Here we report that generating hydrogen peroxide (H2O2) from water and O-2 by organic semiconductor photocatalysts could provide a new basis for clean energy storage without metal and explosion risk. We found that carbon nitride aromatic diimide graphene nanohybrids prepared by simple hydrothermal calcination procedure produce H2O2 from pure water and O-2 under visible light (lambda > 420 nm). Photoexcitation of the semiconducting carbon nitride aromatic diimide moiety transfers their conduction band electrons to graphene and enhances charge separation. The valence band holes on the semiconducting moiety oxidize water, while the electrons on the graphene moiety promote selective two-electron reduction of O-2. This metal-free system produces H2O2 with solar-to-chemical energy conversion efficiency 0.20%, comparable to the highest levels achieved by powdered water-splitting photocatalysts.