- 作者: Tanaka, Ken-Ichi ; Nieuwenhuys, B.E. ; Tamura, Hiroyuki
- 作者服務機構: The Inst. for Solid State Physics, The Univ. of Tokyo, Minato-ku, Tokyo, Japan
- 中文摘要:
When Cu(110), Ni(110), Ag(110) surfaces are exposed to O/sub 2/ at room temperature, one dimensional metal- oxygen strings grow in the <001> direction of the (110) surfaces. A similar phenomenon occurs in the adsorption of H/sub 2/ on Ni(110) surface at room temperature, where the one dimensional strings grow along the <1T0> direction. These phenomena are undoubtedly different from the adsorption induced reconstruction but are explained by the chemical reconstruction involving the formation of quasi- compounds and their self-ordering on the metal surfaces. The chemical reconstruction is indispensably important to understand the structure and catalysis of alloy and bimetallic surfaces.
Pt/sub 0.25/Rh/sub 0.75/(100) alloy surface being active for the reaction of NO with H/sub 2/ is an interesting example. When the Pt-Rh(100) alloy surface is exposed to NO or O/sub 2/ at around 500K, a p(3*1) ordered Rh-O overlayer is obtained on a Pt-enriched 2nd layer by the chemical reconstruction. Ordering of Rh-O in the p(3*1) structure on the Pt(100) surface was reproduced by heating a Rh/Pt(100) bimetallic surface in O/sub 2/, and the chemical reconstruction making the p(3*1) Rh-O overlayer on a Pt enriched 2nd layer was also proved by heating a Pt/Rh(100) bimetallic surface in O/sub 2/ or NO. The activation mechanism of the Pt-Rh alloy and the Pt/Rh bimetallic surfaces by the chemical reconstruction was evidently shown by using a Pt deposited Rh(100), Pt/Rh(100), surface. That is, the Pt/Rh(100) is not so active for the reaction of NO with H/sub 2/, but the reconstructed p(3*1)Rh-O/Pt- layer/Rh(100) surface is very active for the reaction. Therefore, it was concluded that the chemical reconstruction of the Pt -Rh catalyst makes the active surface which is composed of Rh-O and a Pt layer. - 英文摘要: --
- 中文關鍵字: Chemical Reconstruction; Bimetallic Surface; Adsorption; Structure
- 英文關鍵字: 化學重建;雙金屬表面;吸附;結構