Oxygen vacancy promoted methane partial oxidation over iron oxide oxygen carriers in the chemical looping process

• DOI: 10.1039/c6cp06264d
• Publication Date: 2016-11-03T11:56:53Z
• Authors: Zhuo Cheng; Lang Qin; Mengqing Guo; Mingyuan Xu; Jonathan A. Fan; Liang-Shih Fan
• Keywords: Partial oxidation; Partial pressure

We perform ab initio DFT+U calculations and experimental studies of the partial oxidation methane to syngas on iron oxide oxygen carriers elucidate role vacancies in carrier reactivity. In particular, we explore effect vacancy concentration sequential processes dehydrogenation, with lattice oxygen. find that when CH4 adsorbs onto Fe atop sites without neighboring vacancies, it dehydrogenates CHx radicals remaining same site evolves into CO2via complete pathway. presence other hand, formed methyl (CH3) prefers migrate while H from dehydrogenation remains original site, CO via The created process can be healed by diffusion subsurface surface sites, is found outward atoms more favorable than horizontal layer. Based proposed mechanism energy profile, identify rate-limiting steps pathways. Also, increasing not only lowers barriers but also cleavage Fe-C bonds. However, barrier step cannot further decrease reaches 2.5%. fundamental insight help guide design development efficient CLPO processes.