The Effect of Surface Structure on the Decomposition of Nitric-Oxide and Ammonia on Platinum

Temperature programmed desorption (TPD) was used to compare nitric oxide (NO) decomposition on Pt(100), Pt(411), and Pt(211). The three surfaces were predicted to have similar orbital availabilities but different site densities. The measured dissociation fractions were 66, 70, and 66% on Pt(100), Pt(411) and Pt(211) respectively. The NO binding energy on the (100) steps of Pt (211) was unusually strong. The activation energy for N$\sb2$ formation was nearly identical (28 kcal/mol) on Pt(211) and Pt(411). Assuming that NO dissociation occurred at the (100) sites 90% of the NO associated with these sites on Pt(210) dissociated compared to 70% on Pt(411) and 66% on Pt(100). NO dissociation on Pt(100) was inhibited by a (1 x 1) $\to$ (1 x 5) surface reconstruction. Except for some minor effects, the variations in reactivity with changing crystal face were as expected from orbital symmetry and did not scale with site density.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Gohndrone, John Michael

Contributors dc:contributor

• Masel, Richard I.

• Chemistry, Physical
• Engineering, Chemical

Identifier

(UMI)AAI8815344

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/69789