The decoration of TiO2/reduced graphene oxide by Pd and Pt nanoparticles for hydrogen gas sensing
The decoration of TiO2/reduced graphene oxide by Pd and Pt nanoparticles for hydrogen gas sensing
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DOI：
10.1016/j.ijhydene.2012.08.011
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发表时间：
2012-10-01
影响因子：
7.2
通讯作者：
Gholami, M. R.
中科院分区：
文献类型：
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作者：
Esfandiar, A.;Ghasemi, S.;Gholami, M. R.
以还原氧化石墨烯（RGO）为原料，通过简便的制备工艺提高了Pd和pt修饰TiO2纳米粒子的感氢性能。采用溶胶-凝胶法制备了二氧化钛纳米粒子，并通过光还原过程偶联在氧化石墨烯薄片上。通过化学还原将Pd或Pt纳米粒子修饰在TiO2/RGO杂化结构上。x射线光电子能谱分析表明，TiO2纳米粒子对氧化石墨烯进行了还原，并在TiO2和氧化石墨烯薄片之间形成了Ti-C键。在不同温度下，对不同浓度的氢（从100 ppm到10,000 ppm）进行了气体传感研究。在较低温度（180℃）下，对TiO2/RGO样品进行低浓度Pd修饰（2 wt.%），在500 ppm氢气条件下，观察到高灵敏度（92%）和快速响应时间（小于20 s）。RGO薄片通过在这些混合结构中发挥支架作用，为气体扩散提供了新的途径和电流的优先通道。基于上述机理，Pd/TiO2/RGO样品比Pt/TiO2/RGO样品具有更好的传感性能。更大的溢出效应和氢分子在Pd上的解离被认为是Pd/TiO2/RGO中灵敏度增强的可能原因。版权所有(C) 2012，氢能源出版有限责任公司由爱思唯尔有限公司出版版权所有。
Reduced graphene oxide (RGO) was used to improve the hydrogen sensing properties of Pd and Pt-decorated TiO2 nanoparticles by facile production routes. The TiO2 nanoparticles were synthesized by sol-gel method and coupled on GO sheets via a photoreduction process. The Pd or Pt nanoparticles were decorated on the TiO2/RGO hybrid structures by chemical reduction. X-ray photoelectron spectroscopy demonstrated that GO reduction is done by the TiO2 nanoparticles and Ti-C bonds are formed between the TiO2 and the RGO sheets as well. Gas sensing was studied with different concentrations of hydrogen ranging from 100 to 10,000 ppm at various temperatures. High sensitivity (92%) and fast response time (less than 20 s) at 500 ppm of hydrogen were observed for the sample with low concentration of Pd (2 wt.%) decorated on the TiO2/RGO sample at a relatively low temperature (180 degrees C). The RGO sheets, by playing scaffold role in these hybrid structures, provide new pathways for gas diffusion and preferential channels for electrical current. Based on the proposed mechanisms, Pd/TiO2/RGO sample indicated better sensing performance compared to the Pt/TiO2/RGO. Greater rate of spill-over effect and dissociation of hydrogen molecules on Pd are considered as possible causes of the enhanced sensitivity in Pd/TiO2/RGO. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.