Photo-Assisted Hydrogen Evolution in Aqueous Solution of Formic Acid with Silicon which is Supported with Noble Metals
Photo-Assisted Hydrogen Evolution in Aqueous Solution of Formic Acid with Silicon which is Supported with Noble Metals
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DOI：
10.1007/s12633-014-9201-7
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发表时间：
2014
期刊：
影响因子：
3.4
通讯作者：
K. Tsutsumi;Nao Kashimura;K. Tabata
中科院分区：
文献类型：
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作者：
K. Tsutsumi;Nao Kashimura;K. Tabata
硅是用途最广泛的半导体之一，在可见光照射下也显示出光催化活性。我们表明，从10%的甲酸溶液与硅颗粒的析氢是由硅表面上的贵金属的支持增强。最合适的负载金属和相应的试剂，如金属盐或金属纳米颗粒，用于析氢检查。由于观察到二氧化碳的析出作为副产物，并且在存在和不存在可见光照射的情况下，通过所有反应，二氧化碳的量几乎与析出的氢相同，因此我们认为所有析出的氢都是由甲酸的分解产生的。可见光照射下的H2和CO2释放量均大于未照射时的释放量。半导体吸收超带隙光子以分别在导带（CB）和价带（VB）中产生光激发电子（e）和空穴（h+）对。因此，所产生的空穴在甲酸的氧化中被有效地消耗。通过对催化剂的SEM和XPS分析，讨论了光反应过程中放出H2的来源。
Silicon is one of the most versatile semiconductors and also displays photocatalytic activity under visible light irradiation. We show that hydrogen evolution from 10% formic acid solution with silicon particles is enhanced by the support of noble metals on the surface of silicon. The most suitable loading metals and corresponding reagents, such as metal salts or metal nanoparticles, are examined for hydrogen evolution. Because carbon dioxide evolution is observed as a by-product and the amount of carbon dioxide is almost the same as evolved hydrogen through all reactions in the presence and absence of irradiation by visible light, we suggest that all evolved hydrogen is produced by the decomposition of formic acid. Furthermore, both the amounts of evolved H2and CO2in the presence of visible light irradiation are larger than those without irradiation. Semiconductors absorb supra band gap photons to generate photoexcited electron (e) and hole (h+) pairs in the conduction band (CB) and valence band (VB), respectively. Thus, the generated holes are consumed effectively in the oxidation of formic acid. The origin of evolved H2is also discussed from the consideration of SEM and XPS measurements of the catalysts through the photoreactions.