ACTIVATION OF THE PT DEPOSITED RH(100) BIMETALLIC SURFACE BY CHEMICAL ORDERING

被引:28
作者
TAMURA, H [1 ]
SASAHARA, A [1 ]
TANAKA, K [1 ]
机构
[1] UNIV TOKYO,INST SOLID STATE PHYS,MINATO KU,TOKYO 106,JAPAN
关键词
D O I
10.1016/0039-6028(94)90774-9
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
When the Pt deposited Rh(100) surface, Pt/Rh(100), was exposed to 10(-7) Torr of O2 at 780 K, Rh atoms are segregated and the LEED pattern changes from a c(2 X 2) to a p(3 X 1) + p4g p(2 X 2) pattern. This p(3 X 1) + p4g LEED pattern changed to a p(1 X 1) surface at room temperature by exposing it to H2 and was recovered at room temperature by exposure to O2. The p(3 X 1) + p4g surface is stable at 780 K in vacuum but changes to a p(1 X 1) surface at 1000 K. If the p(1 X 1) surface obtained by annealing at 1000 K is heated in 10(-7) Torr of O2 at 780 K, the p(3 X 1) + p4g surface is again recovered. The p(1 X 1) surface annealed at 1000 K is composed of the Pt-enriched topmost layer on a Rh rich 2nd layer but the p(3 X 1) + p4g surface prepared by treating with 02 at 780 K is composed of the Rh-0 surface compound on the Pt enriched 2nd layer. The catalytic reaction of NO + H-2 was compared on the two surfaces, the p(3 X 1) + p4g Rh-rich surface and the p(1 X 1) Pt-rich surface. The surface composed of Rh-0 on the Pt layer was very active for the reaction but the Pt enriched p(1 X 1) surface was inactive for the reaction. From these results, we concluded that the Rh-0 surface compound ordered on the Pt layer is an active structure for the catalysis.
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页码:L379 / L384
页数:6
相关论文
共 19 条
[1]   OXYGEN-INDUCED RESTRUCTURING OF NI(110) STUDIED BY SCANNING TUNNELING MICROSCOPY [J].
EIERDAL, L ;
BESENBACHER, F ;
LAEGSGAARD, E ;
STENSGAARD, I .
ULTRAMICROSCOPY, 1992, 42 :505-510
[2]  
Ertl G., 1990, ANGEW CHEM, V102, P1258
[3]  
HIRANO H, VACUUM, V41, P134
[4]  
HIRANO H, 1989, NIEUWENHUYS SURF SCI, V222, pL804
[6]   SURFACE RECONSTRUCTION OF CU(110) INDUCED BY OXYGEN-CHEMISORPTION [J].
JENSEN, F ;
BESENBACHER, F ;
LAEGSGAARD, E ;
STENSGAARD, I .
PHYSICAL REVIEW B, 1990, 41 (14) :10233-10236
[7]   STRUCTURE DETERMINATION OF AN ADSORBATE-INDUCED MULTILAYER RECONSTRUCTION - (1X2)-H/NI(110) [J].
KLEINLE, G ;
PENKA, V ;
BEHM, RJ ;
ERTL, G ;
MORITZ, W .
PHYSICAL REVIEW LETTERS, 1987, 58 (02) :148-151
[8]   NUCLEATION AND GROWTH OF A H-INDUCED RECONSTRUCTION OF NI(110) [J].
NIELSEN, LP ;
BESENBACHER, F ;
LAEGSGAARD, E ;
STENSGAARD, I .
PHYSICAL REVIEW B, 1991, 44 (23) :13156-13159
[9]  
REN DM, SURF SCI, V84, pL439
[10]   AN EFFECT OF PHONONS ON THE SURFACE SEGREGATION OF RANDOM BINARY-ALLOYS [J].
SAKAI, A ;
SAKURAI, T .
SURFACE SCIENCE, 1984, 138 (01) :159-171