亚洲免费av电影一区二区三区,日韩爱爱视频,51精品视频一区二区三区,91视频爱爱,日韩欧美在线播放视频,中文字幕少妇AV,亚洲电影中文字幕,久久久久亚洲av成人网址,久久综合视频网站,国产在线不卡免费播放

        ?

        Probing the Controlled Oxidative Etching of Palladium Nanorods by Liquid Cell Transmission Electron Microscopy

        2019-01-23 08:21:48DONGGanxingJINChuanhong
        物理化學(xué)學(xué)報(bào) 2019年1期

        DONG Ganxing, JIN Chuanhong

        State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027,P. R. China.

        Abstract: Herein, we report an in situ study of a microscopic process of oxidative etching of palladium nanorods using liquid cell transmission electron microscopy. Oxidative etching is a universal corrosion phenomenon in the natural environment, and has become an effective tool in the fields of materials and nano-science to precisely tailor product sizes. For some noble metal nanocrystals with shape and chemical anisotropy, oxidative etching selectively occurs on specific sites or facets of the nanoparticles and could change the anisotropy. To study the behavior of anisotropic noble metal nanocrystals, it is easier to directly observe the dynamic etching of nanocrystals in solution. Liquid cell electron microscopy is a rapidly developing and powerful technique, and it allows the study of dynamic events occurring in the liquid phase with sub-nanometer resolution and can be used to track the dynamics of reactions in real-time. By recording the changes in morphology and quantitatively analyzing variations in dimensions could allow us to clarify the mechanism involved in the oxidative etching of palladium nanorods. By changing the solution properties, the oxidative etching behaviors of the palladium nanorods could be effectively controlled. Because of the higher chemical reactivity of the apex of the palladium nanorods, oxidative etching preferentially proceeded along the longitudinal direction, showing strong anisotropic behavior. The decrease in the length of the nanorods was more rapid than the decrease in their diameter, and the aspect ratiodecreased continuously throughout the etching process. An isotropic-like etching was observed when the reaction was performed in an ultrathin solution, where the diffusion of reactants and dissolved agents were inhibited due to the confinement effect. In this case,the palladium nanorods kept their rod shape and aspect ratio before being completely dissolved during the etching process.Furthermore, we demonstrate that the tip-deposition of gold can effectively protect the tips of the palladium nanorods from oxidative etching. Contrary to the previous experiment without gold deposition, oxidative etching selectively took place on the lateral sides. The palladium nanorods became progressively thinner and the aspect ratio continuously increased during the etching process. Previous studies on the oxidative etching of nanocrystals by liquid cell electron microscopy focused on the dissolution kinetics of metal nanocrystals with symmetrical structure. The results presented here show successful in situ monitoring of the controlled oxidative etching process of anisotropic noble metal nanocrystals. The presented results should be important for the precise structural tuning of noble metal nanocrystals for various practical applications.

        Key Words: Palladium nanorod; Oxidative etching; In situliquid cell electron microscopy; Anisotropy;Limited-diffusion; Tip protection

        国产精品久久国产精品99 gif| 精品黄色av一区二区三区| 日本加勒比一道本东京热| 日韩一区在线精品视频| 亚洲中文字幕在线第二页 | 丁香婷婷激情综合俺也去 | 国产精品公开免费视频| 天堂女人av一区二区| 国产精品国产三级久久| 大屁股人妻女教师撅着屁股| 日本精品一区二区三区在线视频| 激情综合网缴情五月天| 手机久草视频福利在线观看 | 天天看片视频免费观看| 国内精品久久久久久久久蜜桃| 国产影院一区二区在线| 成人免费看aa片| 波多野结衣免费一区视频| 免费在线观看蜜桃视频| 日本免费一区二区三区影院| 午夜福利理论片高清在线观看| 日韩精品久久久一区 | 亚洲人成77777在线播放网站 | 亚洲色AV性色在线观看| 亚洲一区二区岛国高清| 天天爽夜夜爽夜夜爽精品视频| 无码人妻少妇色欲av一区二区| 色婷婷丁香综合激情| 日本一区二区在线免费看| 亚洲av无码一区二区三区人| 五月激情婷婷丁香| 色老板在线免费观看视频日麻批| 久久99精品久久久久麻豆| 亚洲精品综合欧美一区二区三区| 国产精品久久无码免费看| 加勒比日韩视频在线观看| 精品国产拍国产天天人| 国产精品三级一区二区按摩| 久久夜色精品国产三级| 无码中文字幕日韩专区| 风流少妇又紧又爽又丰满|