Rational Design of Metal-Free Nitrogen-Doped Carbon for Controllable Reduction of CO2 to Syngas

The electrocatalytic reduction of CO₂ (ECO₂RR) to syngas with tunable CO/H₂ ratios offers a promising route for sustainable energy conversion and chemical production. Here, we report a series of N-doped carbon black (NCBx) catalysts with tailored nitrogen species that enable precise control over the composition of syngas. Among the catalysts, NCB3 exhibits the optimal performance, achieving high CO selectivity (64.14%) and activity (1.9 mA cm^-2) in an H-type cell at -0.9 V. Furthermore, NCB3 produces syngas with a wide range of CO/H₂ ratios (0.52 to 4.77) across the applied potentials (-0.5 to -1.0 V). Stability tests confirm the robust durability of NCB3, which maintains consistent activity and selectivity over prolonged electrolysis. This work demonstrates the critical role of nitrogen species in tuning ECO₂RR pathways and establishes a strategy for designing efficient and stable carbon-based catalysts for CO₂ utilization and syngas production.