N2 emission-channel change in NO reduction over stepped Pd(211) by angle-resolved desorption

SURFACE SCIENCE

卷:606

Article

Matsushima, Tatsuo^1,5  Kokalj, Anton²  Orita, Hideo³  Kubo, Toshitaka⁴  Sakurai, Masataka⁵  Kondo, Takahiro⁵  Nakamura, Junji⁵ 

[1] Hokkaido Univ, Catalysis Res Ctr, Sapporo, Hokkaido 0010021, Japan

[2] Jozef Stefan Inst, Ljubljana 1000, Slovenia

[3] Natl Inst Adv Ind Sci & Technol, Nanosyst Res Inst NRI, Tsukuba, Ibaraki 3058568, Japan

[4] Natl Inst Adv Ind Sci & Technol, Nanosyst Res Inst NRI, Tsukuba, Ibaraki 3058565, Japan

[5] Univ Tsukuba, Fac Pure & Appl Sci, Tsukuba, Ibaraki 3058573, Japan

关键词: Nitrogen oxide;    Nitrous oxide;    Reduction;    Nitrogen;    Palladium;    Stepped surface;   

DOI  :  10.1016/j.susc.2012.02.023

来源: Elsevier

【 摘 要 】

A sharp change in the N-2 emission channel from N2O(a) -> N-2(g) + O(a) to N(a) + N(a) -> N-2(g) has been found at around 500 K in a steady-state NO + D-2 reaction over stepped Pd(211) = [(S)3(111) x (100)] by means of angle-resolved desorption. The desorbing N-2 is highly collimated at around 30 off normal toward the step-down direction below about 500 K due to the intermediate N2O decomposition, whereas, above 500 K, the near normally directed desorption due to the recombination of N(a) is relatively enhanced. The N2O decomposition channel is promoted when the reaction is carried out with hydrogen (deuterium) and the channel change is accelerated by quick changes of the amounts of surface hydrogen and oxygen (or NO(a)) into the opposite directions, and enhanced nitrogen removal as ammonia on the resultant hydrogen-rich surface. In the steady-state NO + CO reaction, the N-2 emission channel gradually changes above 500 K toward recombination. A model for the off-normal N-2 emission is briefly described. (C) 2012 Elsevier B.V. All rights reserved.

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