Efficient Electrocatalytic CO2 Reduction to CO by Tuning CdO-Carbon Black Interface

Highly efficient electrochemical CO2 reduction (ECR) was realized by tuning the interface between CdO and carbon black (CB). CdO/CB composites with different amounts of CdO and CB were prepared simply through ultrasonication. The obtained CdO/CB was characterized by a series of techniques including XRD, XPS, and TEM to reveal its composition and morphology. The ECR performance of CdO/CB composites was tested in an H-type cell. An overall ECR faradaic efficiency (FE) as high as 92.7% was achieved at -1.0 V (versus reversible hydrogen electrode) over CdO/CB with 20% (mass fraction) of CdO, in stark contrast to 69.5% over hare CdO. The highest CO FE reached 87.4%. Further control experiments and kinetic studies suggested that the enhanced catalytic activity of CdO/CB was attributed to the large contact area and interface between CdO and CB. In addition. CdO/CB exhibited stable CO FE for at least 10 h of ECR reaction. The easily accessible CdO/CB composites with tunable interface provide a feasible avenue for efficient ECR over economic electrocatalysts.