Transition metal doped rare-earth metal oxide catalysts for dry reforming of methane: first principles calculation

Restricted (Penn State Only)
Author:
Li, Bo
Graduate Program:
Chemical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
June 04, 2018
Committee Members:
  • Michael John Janik, Thesis Advisor
  • Phillip E Savage, Committee Member
  • Xueyi Zhang, Committee Member
Keywords:
  • Dry Reforming of methane
  • Transition metal
  • Ceria
  • Oxygen vacancy
  • DFT+U
Abstract:
Dry reforming of methane (DRM) is an environment-friendly and sustainable chemical technique, since it converts methane and CO2, two most abundant greenhouse gases, into syngas and other high value chemical products. The most common catalyst for DRM reaction is Ni due to its low cost and high catalytic activity but Ni-based catalysts undergo severe deactivation due to coking. transition metal (TM) doped rare earth oxide catalysts have shown promise in the high catalytic activity and coking resistance ability. This thesis applies the first principles calculation method to design Ni and Zr doped CeO2 catalyst model. Density functional theory (DFT+U) method is used to generate the structure-composition-stability relationships. The distribution of Zr with multiple concentrations have been studied in the CeO2 fluorite lattice. The oxygen vacancy effect has also been examined in the bulk and surface Ni-doped CeO2 bulk and surface structure to determine the most stable configuration. The surface chemistry study of Ni-doped CeO2 surface shows that hydrocarbon over the surface is always oxidized and prefers bonding to the oxygen site rather than the Ni site. This result can thermodynamically explain the reason of catalyst coking resistance.