Atomic origins of the high catalytic activity of nanoporous gold
Atomic origins of the high catalytic activity of nanoporous gold
复制标题
DOI：
10.1038/nmat3391
复制
发表时间：
2012-09-01
期刊：
影响因子：
41.2
通讯作者：
Chen, Mingwei
中科院分区：
文献类型：
--
作者：
Fujita, Takeshi;Guan, Pengfei;Chen, Mingwei
与惰性块状金不同，纳米颗粒金已被发现对氧化反应具有显着的催化活性。纳米颗粒金的催化性能强烈地依赖于尺寸和载体，并且在特征尺寸大于5 nm时通常不能观察到催化活性。有趣的是，显着的催化活性可以保留在脱合金纳米多孔金（NPG），即使当其特征长度大于30 nm。在这里，我们报告的NPG催化，其特征在于球面像差校正的透射电子显微镜（TEM）和环境TEM原子的见解。在NPG的弯曲表面上观察到高密度的原子台阶和扭结，与3-5 nm的纳米颗粒相当，其由双曲面状金韧带稳定。原位TEM观察提供了令人信服的证据表明，表面缺陷是活性位点的CO和残留的Ag的催化氧化稳定的原子步骤，通过抑制{111}小面动力学。
Distinct from inert bulk gold, nanoparticulate gold has been found to possess remarkable catalytic activity towards oxidation reactions. The catalytic performance of nanoparticulate gold strongly depends on size and support, and catalytic activity usually cannot be observed at characteristic sizes larger than 5 nm. Interestingly, significant catalytic activity can be retained in dealloyed nanoporous gold (NPG) even when its feature lengths are larger than 30 nm. Here we report atomic insights of the NPG catalysis, characterized by spherical-aberration-corrected transmission electron microscopy (TEM) and environmental TEM. A high density of atomic steps and kinks is observed on the curved surfaces of NPG, comparable to 3-5 nm nanoparticles, which are stabilized by hyperboloid-like gold ligaments. In situ TEM observations provide compelling evidence that the surface defects are active sites for the catalytic oxidation of CO and residual Ag stabilizes the atomic steps by suppressing {111} faceting kinetics.