Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, School of Materials Science & Engineering , Hubei University , Wuhan 430062 , China.
State Center for International Cooperation on Designer Low-carbon & Environmental Materials , Zhengzhou University , 100 Kexue Avenue , Zhengzhou 450001 , China.
ACS Appl Mater Interfaces. 2018 Aug 22;10(33):28199-28209. doi: 10.1021/acsami.8b07816. Epub 2018 Aug 14.
An oriented TiO thin film-based hydrogen sensor has been demonstrated to have excellent sensing properties at room temperature. The exposed high energy surface offers a low energy barrier for H adsorption and dissociation. In this work, rutile TiO with {101} and {002} facets exposed was controllably synthesized by adjusting the ethanol content of the hydrothermal solvent. The crystalline structure, morphologies, and H sensing performance of the samples varied with the relative ratios of {002} and {101} facets. By increasing the ethanol content, the (002) orientation growth was enhanced and the (101) orientation growth was restrained, the size of the nanorods composing the thin film was reduced and the density of the film was increased. All of the prepared TiO nanorod array film-based hydrogen sensors performed very well at room temperature. The TiO hydrogen sensor with both {110} and {002} facets exposed gave a faster response, as well as better repeatability and stability than those with only {002} facets. Density functional theory simulations have been adopted to reveal the surface interaction of H and the TiO surface. The results suggested that H tended to be adsorbed and dissociated on the (002) and (101) surface. There is a very small active barrier for atomic H to recombine into H molecules on the (110) surface. Thin films with lower density, where more (110) surface is exposed, offered more space for H regeneration, leading to shorter response and recovery times as well as higher sensitivity. The (002), (101), and (110) surfaces of rutile TiO synergistically cooperated to complete the whole H sensing process.
一种定向 TiO 薄膜基氢气传感器在室温下表现出优异的传感性能。暴露的高能表面为 H 吸附和离解提供了低能势垒。在这项工作中，通过调整水热溶剂中的乙醇含量，可控合成了具有{101}和{002}面暴露的锐钛矿 TiO。样品的晶体结构、形貌和 H 传感性能随{002}和{101}面的相对比例而变化。通过增加乙醇含量，（002）取向生长得到增强，（101）取向生长受到抑制，组成薄膜的纳米棒的尺寸减小，薄膜的密度增加。所有制备的 TiO 纳米棒阵列薄膜基氢气传感器在室温下表现出非常好的性能。与仅具有{002}面暴露的传感器相比，具有{110}和{002}面暴露的 TiO 氢气传感器具有更快的响应速度以及更好的重复性和稳定性。采用密度泛函理论模拟揭示了 H 与 TiO 表面的表面相互作用。结果表明，H 倾向于在（002）和（101）表面吸附和离解。在（110）表面，原子 H 重新结合成 H 分子的活性势垒非常小。密度较低的薄膜，暴露的（110）表面更多，为 H 再生提供了更多空间，从而导致响应和恢复时间更短，灵敏度更高。锐钛矿 TiO 的（002）、（101）和（110）表面协同合作完成整个 H 传感过程。
