Surface Interrogation Scanning Electrochemical Microscopy of Ni 1– x Fe x OOH (0 < x < 0.27) Oxygen Evolving Catalyst: Kinetics of the “fast” Iron Sites

作者：Hyun S. Ahn, Allen J. Bard · 发表于：Journal of the American Chemical Society · 年份：2015 · DOI：10.1021/jacs.5b10977 · 被引用次数：332 · 研究领域：Electrocatalysts for Energy Conversion、Electrochemical Analysis and Applications、Advanced battery technologies research

Nickel-iron mixed metal oxyhydroxides have attracted significant attention as an oxygen evolution reaction (OER) catalyst for solar fuel renewable energy applications. Here, we performed surface-selective and time-dependent redox titrations to directly measure the surface OER kinetics of Ni(IV) and Fe(IV) in NiOOH, FeOOH, and Ni(1-x)Fe(x)OOH (0 < x < 0.27) electrodes. Most importantly, two types of surface sites exhibiting "fast" and "slow" kinetics were found, where the fraction of "fast" sites in Ni(1-x)Fe(x)OOH matched the iron atom content in the film. This finding provides experimental support to the theory-proposed model of active sites in Ni(1-x)Fe(x)OOH. The OER rate constant of the "fast" site was 1.70 s(-1) per atom.