Investigating the influence of oxygen doping in modulating product distribution for electrocatalytic CO₂ reduction reaction

Efficient carbon recycling hinges on a comprehensive understanding of the mechanics behind electrocatalytic carbon dioxide reduction reactions (ECO₂RR). Here, we have engineered, in-situ growth of CuO featured on O-doped gCN (COG) and ex-situ growth of CuO on bare gCN (CG) respectively, functioned as platforms for disengaging the fundamental of ECO₂RR. The COG holds substantial capacity compared to CG for efficient conversion of CO₂ into hydrocarbons and initiated the C₂ product pathway with enlarged faradaic efficiency (FE). The experimental results indicate that the COG enhanced the product conversion of CH₃OH (FE = 61.5% ± 0.5), C₂H₅OH (FE = 24.7% ± 0.5), and HCOO^– (FE = 6.1% ± 0.5) at −1.1 V Vs RHE. Meanwhile, the CG exhibited the maximum conversion of CO₂ into CH₃OH (FE = 56.4% ± 0.5) at the same potential range. For the CG, the partial current density of CH₃OH (JCH₃OH) is −1.8 mA cm⁻², whereas COG exhibited −4.9 mA cm⁻². Interestingly, in this ECO₂RR, the study of oxygen doping demonstrated that feasible CO₂ conversion, due to its affinity towards CO₂ and high donor density.