Solution phase superoxide as an intermediate in the oxygen reduction reaction on glassy carbon in alkaline media
Solution phase superoxide as an intermediate in the oxygen reduction reaction on glassy carbon in alkaline media
复制标题
DOI：
10.1016/j.electacta.2019.135432
复制
发表时间：
2020-03
影响因子：
6.6
通讯作者：
J. Strobl;N. Georgescu;D. Scherson
中科院分区：
文献类型：
--
作者：
J. Strobl;N. Georgescu;D. Scherson
3-巯基-1-丙醇（3 M1 P）修饰的Au环电极已被用于监测在0.1 M NaOH水溶液中在环盘旋转电极（RRDE）的玻璃碳（GC）盘表面产生的溶液相超氧化物O2−（aq）。在不同转速下进行的测量提供了明确的证据，即O2−（aq）的最大产量是在与极化曲线中的电流最小值相关的电位下获得的，Edisk= 0.3 V vs RHE，约为0.5 V。18%的法拉第效率与此形成鲜明对比的是，在使用Au和Pt圆盘电极的几乎相同的实验中，没有检测到O2−（aq）。这一发现表明，如果超氧化物参与这些金属上的O2（aq）还原机制，它仍然吸附在表面上，随后被还原，或者，如果解吸，其还原速率将足够高，其浓度降低到无法检测到的水平，在官能化的金环的实验条件下。
A 3-mercapto-1-propanol (3M1P)-modified Au ring electrode has been employed to monitor solution phase superoxide, O2−(aq), generated at the surface of a glassy carbon (GC) disk of a ring-disk rotating electrode (RRDE) in 0.1 M NaOH aqueous solutions. Measurements performed at various rotation rates afforded unambiguous evidence that maximum yields for O2−(aq) is attained at potentials associated with a current minimum in the polarization curve at Edisk= 0.3 V vs RHE, with a ca. 18% faradaic efficiency. In stark contrast, no O2−(aq) could be detected in virtually identical experiments involving Au and Pt disk electrodes. This finding indicates that, if superoxide is involved in the mechanism of O2(aq) reduction on these metals, it remains adsorbed on the surface and is subsequently reduced, or, if desorbed, the rate of its reduction would be high enough for its concentration to decrease to undetectable levels at the functionalized Au-ring under the experimental conditions employed.