M. Nkiawete, R. Vander Wal
Penn State University,
United States
Keywords: thermo-catalytic decomposition of methane, carbon catalysts, carbon nanostructure, active sites, deposition rates
Summary:
Until renewable energy and hydrogen generation technology scales, so-called “blue” hydrogen will be a bridge towards the hydrogen economy. Thermo-catalytic decomposition (TCD) is well-suited for the generation of hydrogen from natural gas. In a decarbonization process for fossil fuel—pre-combustion—solid carbon is produced, with potential commercial uses including energy storage. At present, studies linking catalyst active sites to TCD deposition rates are few. In this study, TCD measurements were performed using a hot wall reactor and flat substrates of quartz; an advantageous approach to TCD relative to fixed bed reactors. In this study, a synthetic natural gas blend diluted in an argon carrier served as the initial feed. The test matrix encompassed a series of temperatures (900 – 1,100 ℃) and durations (1 – 12 hrs.). Deposition rates were measured periodically for determination of deposition rate by deposit thickness, using scanning electron microscopy (SEM). The nanostructure of the deposit was evaluated using transmission electron microscopy (TEM) coupled with fringe analysis and Raman spectroscopy. At selected stages during TCD, samples were subjected to activated chemisorption in preparation of active site measurement. Active sites were quantified by X-ray photoelectron spectroscopy (XPS).