Graphene supported plasmonic photocatalyst for hydrogen evolution in photocatalytic water splitting
Graphene supported plasmonic photocatalyst for hydrogen evolution in photocatalytic water splitting
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DOI：
10.1088/0957-4484/25/26/265701
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发表时间：
2014-07-04
期刊：
影响因子：
3.5
通讯作者：
Sorensen, C. M.
中科院分区：
文献类型：
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作者：
Singh, G. P.;Shrestha, K. M.;Sorensen, C. M.
众所周知，贵金属纳米颗粒在可见光区表现出活性吸收，这是因为存在被称为表面等离子体共振（SPR）的独特特征。在这里，我们报告的等离子体激元Au纳米粒子的增强可再生氢（H-2）的演变，通过光催化水裂解的效果。采用水热法制备了石墨烯/TiO 2纳米复合材料，然后通过光沉积法负载Au，制备了等离子体Au/graphene/TiO 2光催化剂。等离子体激元Au和作为助催化剂的石墨烯有效地延长了光生电荷的复合。这种等离子体光催化剂表现出增强的光催化H-2的演变为水裂解在甲醇作为牺牲试剂的存在下。从Au/石墨烯助催化剂的H-2析出速率比纯石墨烯催化剂的H-2析出速率高约9倍。发现最佳石墨烯含量为1.0重量%，产生1.34 mmol的H-2释放（即，26 μ molh（-1）），超过了0.56 mmol（i.例如，112 molh（-1））。这种高的光催化H-2析出活性是由于在石墨烯片上沉积了TiO 2，石墨烯片充当电子受体以有效地分离光生电荷载流子。然而，Au负载显著地增强了H-2的释放，并且达到了12 mmol（i.例如，2.4 mmolh（-1）），石墨烯/TiO 2复合材料上的最佳负载量为2.0 wt% Au。Au的存在下，H-2的释放的增强的结果从SPR效应引起的可见光照射，这提高了被捕获的电子的能量强度以及光催化活性的活性位点。
It is well known that the noble metal nanoparticles show active absorption in the visible region because of the existence of the unique feature known as surface plasmon resonance (SPR). Here we report the effect of plasmonic Au nanoparticles on the enhancement of the renewable hydrogen (H-2) evolution through photocatalytic water splitting. The plasmonic Au/graphene/TiO2 photocatalyst was synthesized in two steps: first the graphene/TiO2 nanocomposites were developed by the hydrothermal decomposition process; then the Au was loaded by photodeposition. The plasmonic Au and the graphene as co-catalyst effectively prolong the recombination of the photogenerated charges. This plasmonic photocatalyst displayed enhanced photocatalytic H-2 evolution for water splitting in the presence of methanol as a sacrificial reagent. The H-2 evolution rate from the Au/graphene co-catalyst was about 9 times higher than that of a pure graphene catalyst. The optimal graphene content was found to be 1.0 wt %, giving a H-2 evolution of 1.34 mmol (i.e., 26 mu molh(-1)), which exceeded the value of 0.56 mmol (i. e., 112 molh(-1)) observed in pure TiO2. This high photocatalytic H-2 evolution activity results from the deposition of TiO2 on graphene sheets, which act as an electron acceptors to efficiently separate the photogenerated charge carriers. However, the Au loading enhanced the H-2 evolution dramatically and achieved a maximum value of 12 mmol (i. e., 2.4 mmolh(-1)) with optimal loading of 2.0 wt% Au on graphene/TiO2 composites. The enhancement of H-2 evolution in the presence of Au results from the SPR effect induced by visible light irradiation, which boosts the energy intensity of the trapped electron as well as active sites for photocatalytic activity.