Structure sensitivity of H2/D2 Isotopic Exchange on Pt/Al2O3 catalysts

Pt-supported catalysts are widely used industrially for hydrogenation reactions. However, the kinetics of hydrogen activation, a critical step for any hydrogenation reaction, is still not well understood on supported Pt surfaces. Recent studies had shown that activity and selectivity vary with Pt nuclearity for the acetylene semihydrogenation reaction, increasing in activity and decreasing in selectivity while increasing the particle size from single atoms (SA) to sub-nanoclusters to nanoparticles (NP), attributing the cause of these differences on activities to the activity of H2 activation in the H/D isotopic exchange reaction. In this work, the kinetics of H2 is studied by performing the H2-D2 isotopic exchange reaction on Pt-supported catalysts with different nuclearity to extract the activation barriers and pre-exponential factors for dissociating adsorption and associative desorption (Eads, Edes, and vads, vdes respectively) from the microkinetic model derived from the Bonhoeffer Farkas mechanism, this to perform a more in-depth analysis regarding the differences in activity when comparing the H2 adsorption energy (Eads+ = Eads-Edes) and frequency factors as a function of nuclearity. Experiments were carried out in a quartz tubular fixed bed reactor coupled with a Mass Spectrometer to analyze the product gas by carrying out both, an integral analysis (from 0 to equilibrium conversion) by performing light-off experiments and differential analysis (low conversions) by performing Arrhenius experiments in the low and high coverage regions.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Chemical Engineering

Department dc:contributor.department

Chemical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2022

Author dc:creator

• Pool Mazun, Ricardo

Chair dc:contributor.committeechair

• Karim, Ayman M.

Committee members dc:contributor.committeemember

• Xin, Hongliang
• Morris, John R.

• Heterogeneous-catalysis
• Kinetics
• Pt
• Alumina
• Hydrogen
• Deuterium
• Reactors
• Engineering
• Energy-eficiency
• Nanoparticle
• Single-Atoms

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

vt_gsexam:35474

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/111848