Tunable Syngas Production through CO₂ Electroreduction on Cobalt–Carbon Composite Electrocatalyst

Controllable concomitant production of CO and H₂ (syngas) during electrochemical CO₂ reduction reactions (CO₂RR) is expected to improve the commercial feasibility of the technology to mitigate CO₂ emissions as the generated syngas can be converted into useful chemicals using the commercial Fischer-Tropsch (FT) process. Herein, we demonstrate the ability of a Co single-atom-decorated N-doped graphitic carbon shell-encapsulated cobalt nanoparticle electrocatalyst (referred as Co@CoNC-900) to controllably produce syngas at low overpotentials during CO₂RR. Through the engineering and modulation of dual active sites for CO₂RR (modified carbon shell with encapsulated Co) and hydrogen evolution reaction (Co-N₄ moieties) within Co@CoNC by varying the annealing temperature, we are able to tune the H₂: CO ratio from 1: 2 to 1: 1 to 3: 2 over a wide range of applied potentials (-0.5 V to -0.8 V versus reversible hydrogen electrode, RHE). This versatile control of H₂: CO ratio in CO₂RR reaction brings up significant opportunity of using CO₂ and H₂O and renewable energy for producing a range of chemicals.