Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14854, USA.
Chem Soc Rev. 2014 Feb 21;43(4):1107-17. doi: 10.1039/c3cs60215j.
This review discusses the latest advances in using single-molecule microscopy of fluorogenic reactions to examine and understand the spatiotemporal catalytic behaviors of single metal nanoparticles of various shapes including pseudospheres, nanorods, and nanoplates. Real-time single-turnover kinetics reveal size-, catalysis-, and metal-dependent temporal activity fluctuations of single pseudospherical nanoparticles (<20 nm in diameter). These temporal catalytic dynamics can be related to nanoparticles' dynamic surface restructuring whose timescales and energetics can be quantified. Single-molecule super-resolution catalysis imaging further enables the direct quantification of catalytic activities at different surface sites (i.e., ends vs. sides, or corner, edge vs. facet regions) on single pseudo 1-D and 2-D nanocrystals, and uncovers linear and radial activity gradients within the same surface facets. These spatial activity patterns within single nanocrystals can be attributed to the inhomogeneous distributions of low-coordination surface sites, including corner, edge, and defect sites, among which the distribution of defect sites is correlated with the nanocrystals' morphology and growth mechanisms. A brief discussion is given on the extension of the single-molecule imaging approach to catalysis that does not involve fluorescent molecules.
这篇综述讨论了使用荧光反应的单分子显微镜来检查和理解各种形状的单金属纳米粒子（包括伪球、纳米棒和纳米板）的时空催化行为的最新进展。实时单轮动力学揭示了单伪球形纳米粒子（直径<20nm）的尺寸、催化和金属依赖性的时间活性波动。这些时间催化动力学可以与纳米粒子的动态表面重构相关联，其时间尺度和能量可以被量化。单分子超分辨催化成像进一步能够直接量化单伪 1-D 和 2-D 纳米晶体不同表面位点（即，端 vs. 侧，或角、边缘 vs. 面区）的催化活性，并揭示了同一表面面区内的线性和径向活性梯度。这些单纳米晶体内部的空间活性模式可以归因于低配位表面位点（包括角、边缘和缺陷位点）的不均匀分布，其中缺陷位点的分布与纳米晶体的形态和生长机制相关。简要讨论了将单分子成像方法扩展到不涉及荧光分子的催化领域。
