Theory guided screening of catalyst materials for hydrogen production from methane via plasma-catalysis

Natural gas which mainly consists of Methane (CH₄) is a major byproduct in oil drilling. Since it’s hard to store CH₄, methane flaring is a common practice in the petroleum industry. Production of hydrogen (H₂) gas from CH₄ is a viable alternative to deal with excess CH₄ if we can safely manage solid carbon byproduct without poisoning the catalyst surface. Conventional processes to activate CH₄ require extreme temperatures and pressures. In this work we propose plasma-catalytic conversion of CH₄ directly to H₂ gas and solid carbon, which can be done at ambient pressures and lower temperatures due to plasma activation (plasma generated from renewable electricity). Non-thermal plasma pushes reactants to excited states (non-equilibrium) which breaks scaling relationships of CH₄ activation. This allows us to easily activate CH₄ on metals which bind to C weakly. Weak C binding energy makes it easier to manage coke formation effectively without catalyst poisoning. In this work, we used density functional theory and nudged elastic band calculations to get micro-kinetic models from which theoretical turnover frequencies (TOF) are calculated (with and without plasma) for various transition metal catalysts. Our preliminary calculations show that transition metals like Co & Ir have several orders of magnitude improvement in TOF with the plasma activation. Going forward our experimental collaborators will use our computational results to choose appropriate catalyst candidates.