CO2 Reduction at Low Overpotential on Cu Electrodes Resulting from the Reduction of Thick Cu2O Films
CO2 Reduction at Low Overpotential on Cu Electrodes Resulting from the Reduction of Thick Cu2O Films
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DOI：
10.1021/ja3010978
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发表时间：
2012-05-02
影响因子：
15
通讯作者：
Kanan, Matthew W.
中科院分区：
文献类型：
--
作者：
Li, Christina W.;Kanan, Matthew W.
通过在空气中退火Cu箔和电化学还原所得到的Cu 2 O层来制备修饰Cu电极。这些电极的CO2还原活性表现出强烈的依赖于初始厚度的Cu 2 O层。通过在130 ℃下退火形成的薄Cu 2 O层导致电极的活性与多晶Cu的活性没有区别。相比之下，在500 ℃下形成的厚度>=类似于3 μ m的Cu 2 O层导致电极表现出大的粗糙度因子，并且需要比多晶Cu低0.5V的过电位来以比H2O更高的速率还原CO2。这些特征的组合导致CO2还原几何电流密度> 1 mA/cm（2），过电位< 0.4 V，活性水平高于在可比条件下评估的所有先前报道的金属电极。此外，改性电极的活性在几个小时的过程中是稳定的，而多晶Cu电极在相同条件下在1小时内表现出失活。这里描述的电极可能是特别有用的，用于阐明Cu的结构特性，确定CO2和H2O还原之间的分布，并提供了一个有前途的铅电解燃料合成的实用催化剂的发展。
Modified Cu electrodes were prepared by annealing Cu foil in air and electrochemically reducing the resulting Cu2O layers. The CO2 reduction activities of these electrodes exhibited a strong dependence on the initial thickness of the Cu2O layer. Thin Cu2O layers formed by annealing at 130 degrees C resulted in electrodes whose activities were indistinguishable from those of polycrystalline Cu. In contrast, Cu2O layers formed at 500 degrees C that were >= similar to 3 mu m thick resulted in electrodes that exhibited large roughness factors and required 0.5 V less overpotential than polycrystalline Cu to reduce CO2 at a higher rate than H2O. The combination of these features resulted in CO2 reduction geometric current densities > 1 mA/cm(2) at overpotentials < 0.4 V, a higher level of activity than all previously reported metal electrodes evaluated under comparable conditions. Moreover, the activity of the modified electrodes was stable over the course of several hours, whereas a polycrystalline Cu electrode exhibited deactivation within 1 h under identical conditions The electrodes described here may be particularly useful for elucidating the structural properties of Cu that determine the distribution between CO2 and H2O reduction and provide a promising lead for the development of practical catalysts for electrolytic fuel synthesis.