Electrified methane upgrading via non-thermal plasma: Intensified single-pass ethylene yield through structured bimetallic catalyst

Abstract

Chemical valorization of methane (CH₄) via modular electrified reactors could represent a profitable avenue for biogas producers. Ethylene (C₂H₄) is the most valuable product due to its large demand that results in high energy cost and carbon emissions. However, alternative electrified processes proposed so far cannot compete with the state-of-the-art fossil route in terms of energy efficiency. The catalytic plasma reactor presented in this work achieves 34.4 % C₂H₄ yield from non-oxidative CH₄ coupling, by integrating a bimetallic Pd-Ag catalyst on the surface of a 3D-printed structured electrode in a nanosecond-pulsed-discharge plasma reactor. This performance sets a new benchmark for alternative C₂H₄ production, potentially relying purely on renewable energy. Onsite energy generation via the excess hydrogen produced in the process could allow recovery of 16 % of the input energy. Moreover, the process produces solid carbon deposit that can be collected on the surfaces in proximity of the plasma discharge. This residue shows amorphous features and significant incorporation of metal particles coming from the electrodes surface. Hence, its low surface area hampers its application as carbon black analogue.