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首页> 外文期刊>Chemistry: A European journal >Enhanced Photocatalytic Hydrogen-Production Performance of Graphene–Zn_xCd_(1-x)S Composites by Using an Organic S Source
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Enhanced Photocatalytic Hydrogen-Production Performance of Graphene–Zn_xCd_(1-x)S Composites by Using an Organic S Source

机译：有机S源增强石墨烯–Zn_xCd_（1-x）S复合材料的光催化产氢性能

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In response to the increasing concerns over energy and environmental sustainability, photocatalytic water-splitting technology has attracted broad attention for its application in directly converting solar energy to valuable hydrogen (H_2) energy. In this study, high-efficiency visiblelight- driven photocatalytic H_2 production without the assistance of precious-metal cocatalysts was achieved on graphene– Zn_xCd_(1-x)S composites with controlled compositions. The graphene-Zn_xCd_(1-x)S composites were for the first time fabricated by a one-step hydrothermal method with thiourea as an organic S source. It was found that thiourea facilitates heterogeneous nucleation of Zn_xCd_(1-x)S and in situ growth of Zn_xCd_(1-x)S nanoparticles on graphene nanosheets. Such a scenario results in abundant and intimate interfacial contact between graphene and Zn_xCd_(1-x)S nanoparticles, efficient transfer of the photogenerated charge carriers, and enhanced photocatalytic activity for H_2 production. The highest H_2-production rate of 1.06 mmolh~(-1)g~(-1) was achieved on a graphene–Zn_(0.5)Cd_(0.5)S composite photocatalyst with a graphene content of 0.5 wt%, and the apparent quantum efficiency was 19.8% at 420 nm. In comparison, the graphene–Zn_xCd_(1-x)S composite photocatalyst prepared by using an inorganic S source such as Na_2S exhibited much lower activity for photocatalytic H_2 production. In this case, homogeneous nucleation of Zn_xCd_(1-x)S becomes predominant and results in insufficient and loose contact with the graphene backbone through weak van der Waals forces and a large particle size. This study highlights the significance of the choice of S source in the design and fabrication of advanced graphene-based sulfide photocatalytic materials with enhanced activity for photocatalytic H_2 production.
机译：为了响应对能量和环境可持续性的日益关注，光催化水分解技术因其在将太阳能直接转化为有价值的氢（H_2）能源方面的应用而受到广泛关注。在这项研究中，在具有可控成分的石墨烯-Zn_xCd_（1-x）S复合材料上，无需借助贵金属助催化剂就可以高效地利用可见光驱动光催化H_2的生产。石墨烯-Zn_xCd_（1-x）S复合材料是通过一步一步水热法以硫脲为有机S源制备的。发现硫脲促进了Zn_xCd_（1-x）S的异质成核和Zn_xCd_（1-x）S纳米粒子在石墨烯纳米片上的原位生长。这种情况导致石墨烯与Zn_xCd_（1-x）S纳米粒子之间充分而紧密的界面接触，光生电荷载体的有效转移以及增强的H_2生产光催化活性。在石墨烯含量为0.5 wt％的石墨烯-Zn_（0.5）Cd_（0.5）S复合光催化剂上，H_2的最高产率为1.06 mmolh〜（-1）g〜（-1） 420 nm处的效率为19.8％。相比之下，使用诸如Na_2S之类的无机S来源制备的石墨烯-Zn_xCd_（1-x）S复合光催化剂表现出低得多的生产H_2的活性。在这种情况下，Zn_xCd_（1-x）S的均匀成核变得占优势，并由于弱的范德华力和大粒径而导致与石墨烯骨架的接触不充分和疏松。这项研究突出了选择S源在设计和制造具有增强的光催化H_2生产活性的先进石墨烯基硫化物光催化材料中的重要性。

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