Plasma-Driven Carbon Mobilization Creates a Transient Near-Surface Carbonaceous Interphase for Selective CO2 Conversion into CO.

Carbon beds enhance plasma-assisted CO2 conversion into resources, but are commonly treated as stationary reactant surfaces. Here, we show that nonthermal plasma (NTP) continuously mobilizes and reconstructs carbon, generating a transient near-surface carbonaceous interphase. In this study, we test these properties of carbon beds as enabling selective CO production during CO2 decomposition under low-temperature plasma conditions. Graphene oxide/chitosan-derived carbons, amorphous carbon, and graphite were examined under CO2 and Ar using gas-phase FTIR, time-resolved SEM, and Raman spectroscopy. GO@CHT-650 displayed the highest CO2 conversion into CO as well as oxygen-scavenging selectivity. Carbonaceous nanodeposits formed under NTP, developed continuously with exposure time, remained confined to the C-surface, and exhibited morphologies and dimensions dependent on the parent carbon structure. Raman analysis showed that the reconstructed phase remained predominantly disordered. These observations link plasma-driven carbon mobility with reactor performance and reveal a catalyst-reactant duality: individual carbon species are consumed stoichiometrically, whereas the dynamically reconstructed interphase persists as the reaction medium. Efficient plasma-assisted CO2 conversion into CO, therefore, requires a transient near-surface carbonaceous interphase created and sustained by the plasma itself.