Trimethylphosphine-Assisted Surface Fingerprinting of Metal Oxide Nanoparticle by 31P Solid-State NMR: A Zinc Oxide Case Study
Trimethylphosphine-Assisted Surface Fingerprinting of Metal Oxide Nanoparticle by 31P Solid-State NMR: A Zinc Oxide Case Study
复制标题
DOI：
10.1021/jacs.5b12080
复制
发表时间：
2016-02-24
影响因子：
15
通讯作者：
Tsang, Shik Chi Edman
中科院分区：
文献类型：
--
作者：
Peng, Yung-Kang;Ye, Lin;Tsang, Shik Chi Edman
纳米金属氧化物正广泛应用于工业、商业和个人产品（半导体、光学、太阳能电池、催化剂、油漆、化妆品、防晒霜等）。然而，由于缺乏一种简单的表征技术，表面特征（暴露平面、缺陷和化学功能）与理化性质的关系并没有得到很好的研究。在本研究中，在三甲基膦（TMP）作为化学探针的帮助下，使用固态P-31 MAS NMR在各种ZnO样品上绘制表面。类似于XRD给出晶体的结构信息，这种新的表面指纹技术不仅提供定性（化学位移），而且还提供定量（峰强度）的浓度和分布的阳离子和阴离子，氧空位和羟基的各个方面的信息从单个解卷积的P-31 NMR谱。在此基础上，揭示了直接表面氧化光催化中心点OH自由基生成的新机制，这对个人护理产品中使用纳米氧化物的安全性具有重要意义。
Nano metal oxides are becoming widely used in industrial, commercial and personal products (semiconductors, optics, solar cells, catalysts, paints, cosmetics, sun-cream lotions, etc.). However, the relationship of surface features (exposed planes, defects and chemical functionalities) with physiochemical properties is not well studied primarily due to lack of a simple technique for their characterization. In this study, solid state P-31 MAS NMR is used to map surfaces on various ZnO samples with the assistance of trimethylphosphine (TMP) as a chemical probe. As similar to XRD giving structural information on a crystal, it is demonstrated that this new surface-fingerprint technique not only provides qualitative (chemical shift) but also quantitative (peak intensity) information on the concentration and distribution of cations and anions, oxygen vacancies and hydroxyl groups on various facets from a single deconvoluted P-31 NMR spectrum. On the basis of this technique, a new mechanism for photocatalytic center dot OH radical generation from direct surface--OH oxidation is revealed, which has important implications regarding the safety of using nano oxides in personal care products.