(673e) Dynamic Modulation of Surface Carbon and Oxygen Vacancies for Sustained Chemical Looping Production of Syngas on 5wt.%Ni/Ce0.6Zr0.4O2 Catalyst.

Syngas, a combination of carbon monoxide (CO) and hydrogen (H₂), is a precursor to many chemicals and fuels, contributing to the billion-dollar global hydrocarbon industry. Chemical looping reforming (CLR) of the greenhouse gases – methane (CH₄) and carbon dioxide (CO₂) allows for energy-efficient production of syngas. 5wt.% nickel (Ni) on ceria-zirconia (5wt%Ni@Ce_0.6Zr_0.4O₂) mixed metal oxide catalyst was investigated here to explore the pathways for sustained syngas production without deactivating the catalyst. The CLR of CH₄ with CO₂ was conducted on varying redox states of the catalyst. In order to elucidate the reaction performance dependence on the intrinsic surface redox states of the catalyst, we performed several operando studies – in-situ Fourier transform spectroscopy, and in-situ Raman spectroscopy. Most importantly, the effect of surface concentration of methane-activated carbon, and oxygen vacancies on the intrinsic kinetics of syngas production was probed in the Temporal Analysis of Products (TAP) reactor. With the gas-gas interactions eliminated under TAP-operational regimes, the experimental data solely reflects the effect of gas-catalyst interactions. This high-volume (millisecond resolution) data containing intrinsic surface interaction insights was decomposed into independent surface interaction modes through advanced statistical models. These intrinsic reaction performance insights, coupled with bulk and surface characterization of the catalysts provide a deeper understanding of the surface processes, as the catalysts evolve dynamically under CLR conditions. Syngas production was reported for over 10 cycles of CLR with CH₄ and CO₂ conversions higher than 90%, with a CO selectivity of more than 90% as well. Elucidation of this dynamic evolution of surface species on the catalyst and their intricate structure-function relationship will aid in designing reaction protocols for enhanced CLR reaction performance.