| 초록 |
Electrochemical CO2 reduction reaction (CO2RR) can produce value-added chemical or fuels in moderate reaction environment. Due to major issues for CO2 reduction such as high overpotential, product selectivity and stability, good catalysts are essential for efficient CO2 conversion. Au is one of metal catalysts with the highest activity to produce CO in aqueous solution. However, low cost-effectiveness and short catalytic life-time still remain as main obstacles for practical utilization. In this talk, we present a facile electrochemical strategy to develop Au nanostructures on thin film type for higher CO2RR activity. According to the conditions (e.g. anodic potential and reducing current densities) of our proposed electrochemical process for Au nanostructures, Au surface morphologies can be controlled to pore- and pillar-like structures. Both Au nanostructures exhibit significantly enhanced CO selectivity at a low overpotential than pristine Au thin film due to higher active sites. In particular, morphology-dependent CO2RR performance which are imperative for catalysts design is discussed in different potential region. In addition, we show the dilute Cu alloying strategy in Au nanostructures for long-term stability. To synthesize nanostructured Au with dilute Cu alloying, electrochemical or underpotential deposition of Cu was carried out prior to electrochemical process for Au nanostructures. While dilute Cu alloyed Au nanostructures show higher CO2RR activities (e.g. overpotential and CO selectivity) as good as Au nanostructures without Cu alloying, the durability with Cu alloying was dramatically improved as compared to without Cu. Finally, we briefly introduce in-situ tailoring technique with our electrochemical process to re-active the degraded Au catalysts especially by utilizing Cu impurities in electrolyte during CO2 electroreduction process for more robust and efficient CO2 conversion. |
