Defect-enabled local high-temperature field within carbon to promote in-plane integration of an electrocatalyst for CO2-to-CO conversion

The efficient coupling of metal-containing complexes with carbon supports is a preferred method to maximize their intrinsic electrocatalytic activity. Herein, a defect-enabled local high-temperature field was precisely induced via microwave irradiation, allowing the in-plane integration of metal-containing complexes and carbon supports. In particular, under an energetic microwave input, N,N-dimethylformamide was ingeniously used to preset defect placeholders via the adsorption/anchoring of nitrogen species. Next, the created defects triggered concentrated electromagnetic wave attenuation, which further converted into Joule heating. Finally, these local high-temperature fields favored the spatial interlocking and topological conversion of Fe-macrocycles, as confirmed by multiscale spectroscopy, finite element analysis, and density functional theory. The compact in-plane microstructure endowed this electrocatalyst with a superior high turnover frequency of 241 000 h⁻¹ for CO₂-to-CO conversion. Moreover, the reaction could be operated in a scaled-up membrane electrode assembly with an effective electrode area of 5 × 5 cm² at a total current density of 200 mA cm⁻². This work provides a novel path for the precise fabrication of well-defined materials with excellent electrocatalytic activity.