Selective CO2 Reduction on Zinc Electrocatalyst: The Effect of Zinc Oxidation State Induced by Pretreatment Environment

Here, we have developed porous nanostructured Zn electrocatalysts for CO 2 reduction reaction (CO 2 RR), fabricated by reducing electrodeposited ZnO (RE-Zn) to activate the CO 2 RR electrocatalytic performance. We discovered that the electrochemical activation environment using CO 2 -bubbled electrolyte during reducing ZnO in a pretreatment step is important for highly selective CO production over H 2 production, while using Ar gas bubbling instead can lead to less CO product of the Zn-based catalyst in CO 2 RR later. The RE-Zn activated in CO 2 -bubbled electrolyte condition achieves a Faradaic efficiency of CO production (FE CO ) of 78.5%, which is about 10% higher than that of RE-Zn activated in Ar-bubbled electrolyte. The partial current density of CO product had more 10-fold increase with RE-Zn electrodes than that of bulk Zn foil at −0.95 V vs RHE in KHCO 3 . In addition, a very hi…