An electrochemical micromonolithic membrane reactor for one-step sustainable covalorization of CH4 and CO2 to C2+ and CO

The valorization of CH 4 and CO 2 into valuable chemicals is a long-standing research challenge. It is typically realized through a multistep catalytic process beginning with syngas production via dry reforming of methane. Herein, we propose to achieve single-step conversion in an electrochemical membrane reactor powered by renewable electricity. A novel electrochemical micromonolithic membrane reactor (EMMR) is designed to decouple CH 4 conversion and CO 2 conversion via the O 2− conducting membrane process (i.e., reaction–separation–reaction). On the CH 4 conversion side, the use of tailored catalysts and reactor configurations reveals a multizone reaction mechanism governing selective CH 4 coupling, highlights the critical oxygen-rich wall effect, and provides in-depth guidance for further reactor design. For the reaction coupling process, the EMMR achieves super-dry conversion by utilizing 2.83 CO 2 molecules per CH 4 and enables one-step direct production of C 2+ and CO. The EMMR system demonstrates 30-h operational stability, and the conceptual process design results in an energy consumption of 57.19 kWh/kgC 2+ with a process sustainability of −14.11 kgCO 2 /kgC 2+. These findings highlight the potential of EMMR as a sustainable platform for carbon circularity and electrified chemical manufacturing. • Novel and practical electrochemical micromonolithic membrane reactor. • Fully electrified one-step covalorization of CH 4 and CO 2 to C 2+ and CO. • Multizone reaction mechanism and critical oxygen-rich wall effect. • EMMR uses up to 2.83 CO 2 per CH 4 and presents negative CO 2 emissions. • Process system sustainability: −14.11 kgCO 2 /kgC 2+ and 19.79 kgCO/kgC 2+ .