Integrated electrically-driven CO2 methanation and dry reforming for efficient and flexible syngas production

Abstract An electrically-driven, integrated catalytic process combining CO2 methanation (Sabatier reaction) and dry reforming of methane (DRM) was demonstrated for efficient CO2 conversion to tunable syngas. Spiral-shaped Ru/CeO2 and Ni/Al2O3–CeO2 catalysts were directly heated via Joule-heating without external furnaces, enabling rapid temperature control and precise energy input. In the first stage, CO2 was efficiently hydrogenated into CH4, achieving stable operation with about 50% CO2 conversion at 15 W of input power. The resulting methane-rich stream was subsequently reformed into syngas (H2 + CO) at adjustable electrical inputs (40 to 120 W) in the second-stage DRM reactor. Increasing input power significantly enhanced CH4 conversion, achieving near-complete conversion at 120 W. Residual hydrogen from methanation effectively suppressed carbon deposition on the DRM catalyst, maintaining stable catalytic performance over a continuous 10-h durability test. Exergy analysis identified an optimal H2/CO2 feed ratio of 2.5, providing the best overall efficiency and maximum added value from electrical energy input. This integrated system offers a promising route for flexible syngas production from renewable energy and CO2, contributing toward the realization of carbon neutrality.