The role of PdZn alloy formation and particle size on the selectivity for steam reforming of methanol
EMSL Project ID
19829
Abstract
Pd/ZnO has been shown in recent years to possess high selectivity towards CO2 during methanol steam reforming. It is commonly assumed that PdZn alloy formation is essential to achieve high selectivity towards CO2. The simplest method to form a PdZn alloy is to treat a Pd/ZnO catalyst at elevated temperatures in H2, generally > 350◦C. The high temperature treatment, while transforming Pd to PdZn, also leads to particle growth. Therefore making a catalyst with small PdZn alloy particles would be desirable to get a higher activity. However, our recent results show that the catalyst selectivity depends on the PdZn alloy particle size. The smaller the particle size the lower the selectivity to CO2. The goal of this work is to understand the role of PdZn particle size and the role of the support on catalyst activity and selectivity. We would like to perform two types of studies using the EMSL facilities. 1. The first objective is to perform computational modeling via density functional theory (DFT) to investigate the effect of PdZn particle size on the density of states and adsorption energies of HCHO, which is a known reaction intermediate in the pathway for methanol reforming.
2. The second objective is to utilize the catalyst characterization facilities to study the adsorption desorption properties of methanol and suspected reaction intermediates using the RXM-100 instrument.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2006-09-07
End Date
2009-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Lebarbier VMC, Y Wang, AK Datye, B Halevi, JM Vohs, E Jeroro, B Kiefer, EL Kunkes, R Schlogl, E Peterson, A DelaRiva, M Havecker , and M Behrens. 2010. "Aerosol-Derived Bimetallic Alloy Powders: Bridging the Gap." PNNL-SA-76995, Pacific Northwest National Laboratory, Richland, WA.