Enhanced Methane-to-Products Conversion in Solid Oxide Cells by Tuning Catalyst Surface Properties

Abstract

The integration of catalytic active layers into solid oxide fuel cells (SOFCs) offers a unique route for coupling the production of value-added chemicals with power generation. This study reports the use of Ca-doped lanthanum–ceria oxide (La0.5Ce0.38Ca0.12O2−δ, LCCaO) as a catalytic layer in SOFCs. Calcium incorporation modifies the defect chemistry and surface basicity of the oxide, as indicated by Raman spectroscopy and chemisorption analyses, enhancing C2 selectivity in the oxidative coupling of methane (OCM). These features are reflected under SOFC operation, in which controlled modulation of the effective O2–/CH4 ratio through generated current density and methane concentration enables tuning between selective C–C coupling and deep oxidation. At 850 °C with a generated current density of 20 mA cm–2, the system achieves ∼74% C2 selectivity with a production rate of ∼1.4 mmol gcat–1 min–1, corresponding to ∼0.03 mmol cm–2 min–1. These results demonstrate that catalytic-assisted SOFCs enable methane conversion coupled with electricity generation, with catalytic layer composition serving as a key parameter for selectivity control.