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Electrochemically-driven dynamic surface chemistry breaks the selectivity-conversion tradeoff in the oxidative coupling of methane

Year: 2026
Type: preprint
Abstract: The partial oxidation of methane to C2 products such as ethylene (C2H4) and ethane (C2H6) is a notoriously challenging catalytic reaction since the key properties, namely the C2 selectivity and CH4 conversion, scale inversely with each other. Despite decades of research on catalyst design, this fundamental C2 selectivity-CH4 conversion tradeoff remains a preeminent challenge.1 While traditional thermochemical catalyst design approaches seem inadequate to surmount said challenge, the electrochemical oxidative coupling of methane (EOCM) presents an alternative approach to enhance catalytic performance by dynamically altering the working state of the catalyst. In this study, we use (La, Sr)1-xTiO3±δ as a model system to demonstrate how electrochemistry enables one to dynamically tune the surface chemistry for enhancing C2 selectivity. Depending on the bulk composition, we observe either step changes in C2 selectivity or even a continuously increasing C2 selectivity trend by using La0.24Sr0.60TiO3-δ: this composition, once electrochemically activated, can break the traditional OCM tradeoff. We demonstrate that any C2 selectivity enhancement effects are determined by the surface La/Ti and Sr/Ti ratios which dynamically evolve under electrocatalytic conditions. The enrichment of La at these surfaces is central to enhanced C2 selectivity values and is crucially modulated by both the initial surface and bulk composition. The results presented herein highlight the potential of electrochemical materials activation for overcoming traditional challenges in partial methane oxidation and provide guidance on materials design for maximizing the C2 selectivity of EOCM.
Source: ChemRxiv
DOI: 10.26434/chemrxiv.15010710/v1
Language: English
Subfield: Catalysis
Open Access status: green
OpenAlex ID: W7223021002
Cites: 57
Cited by:
Related to: 10