(50c) Synergistic Methane and Biomass Co-Feeding for Hydrogen and Carbon Nanotube Production on Ni-Mo/MgO Catalysts

Hydrogen has emerged as an important energy carrier for providing clean energy. Its utilization leads exclusively to water production, offering a clean and sustainable pathway towards reducing carbon emissions. Methane pyrolysis has emerged as a promising alternative for hydrogen production without CO₂ emissions, generating solid carbon as a valuable by-product and then this carbon can be stored or utilized as fuel in the future. In this study, we explore the synergistic effects of combining methane with other biomass-derived compounds such as water, acetic acid, and m-cresol in the production of hydrogen and carbon nanotubes over Ni-Mo/MgO catalysts. Figure 1 demonstrates the advantageous influence of co-feeding water in the process of carbon nanotube growth. Our findings further reveal that the addition of water reduces the activation energy by ~100 kJ/mol compared to methane conversion alone over Ni-Mo/MgO, which we deconvolute into the splitting and reaction with surface carbon species from cleanup of catalyst surface leading to consistent exposure of more active surface features. We delve into the impact of these oxygenated compounds on carbide stabilization, which acts as a carbon sink, and catalyst deactivation. Here, we also employed multiple spectroscopic approaches such as Raman, TEM, XPS and XRD to gain a comprehensive understanding of the evolution of this dynamic catalyst under reaction conditions, complemented by DFT calculations. We also discuss tradeoffs associated with the use of different active metals for methane decomposition and assess the impact of their activity when co-feeding oxygenated compounds.