Reactions on Surfaces

Question 1

Eiley-Rideal reactions

Answer 1

adsorption of 1st reactant, collision of gas phase reactant with adsorbed reactant to give product and product desorption

Question 2

Limiting cases of Eiley-Rideal reactions

Answer 2

low pressures, low surface conc of adsorbed reactant, baPa on bottom becomes negligible
high pressures, high surface conc of adsorbed species, 1 becomes negligible

Question 3

Langmuir-Hinshelwood reactions

Answer 3

adsorption of reactants, diffuse across surface and find each other, react to give product which desorbs

Question 4

Langmuir-Hinshelwood unimolecular limiting cases

Answer 4

low pressures, low surface conc of adsorbed reactant, baPa on bottom becomes negligible
high pressures, high surface conc of adsorbed reactant, 1 becomes negligible

Question 5

Langmuir-Hinshelwood bimolecular limiting cases

Answer 5

low surface concentrations of A or B, bottom row negligible
low surface conc of A wrt B due to low gas pressures or weak adsorption of A wrt B, baPa on denominator negligible

Question 6

Kasemo-Harris reactions

Answer 6

2 species adsorb, one species forms hot atom (usually via photolysis), produces atom/fragment with energy above barriers to diffusion but still bound to surface, hot fragment shoots across surface and hits other reactant to give product, leaves hot fragment behind and product desorbs