國立清華大學 材料科學工程學系
專題演講公告
Title：New Insights into
Catalysis of Intermetallic Compounds and Porous Au
Speaker：An-Pang Tsai 蔡安邦 院士
(Institute of
Multidisciplinary Research for Advanced Materials, Tohoku University)
Time：2019. 01. 09 (Wed.) 10：00 ~ 12：00
Location：Delta Building
401 (National Tsing Hua University)
Abstract：
New insights into catalysis in terms of electronic
structures and microstructure have been studied. An intermetallic
compound, PdZn, reveals similar valence electron density of states to pure Cu,
has been testified by energy band calculation and X-ray photoelectron
spectroscopy (XPS) [1]. The catalytic function was verified to be identical for
the PdZn and Cu, and hence intermetallic compound like PdZn is viewed as a
pseudoelement of Cu. A strong correlation between electronic structures and
catalytic properties in a series of Heusler have also been verified [2].
On the other hand, we describe a new kind of
low-coordinated atomic sites which can contribute to the catalytic activity of porous
Au. Porous Au prepared by dealloying Al2Au exhibit high catalytic reactivity
towards CO oxidation [3]. The presence of quite common twinning defects in the
fcc lattice of porous Au significantly correlates with the catalytic activity.
On the {211} surfaces of porous Au the twinning defects form chains of six-fold
coordinated Au atoms which we denoted as W-chains. The W-chains form long rows
of active Au sites. DFT calculations show that on the W-chains dioxygen
chemisorbs and is activated.
[1] A.P. Tsai, et al., Acc. Chem. Res. 50(2017)2879
[2] T. Kojima et al., Sci. Adv., 4(2018)eaa6063
[3] M. Krajci, S. Kameoka, A.P. Tsai, J. Chem. Phys. 145(2016)084703