BalaKrishnan Arjun, Blanc Niclas, Hagemann Ulrich, Gemagami Parham, Wonner Kevin, Tschulik Kristina, Li Tong
Institute for Materials, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801, Bochum, Germany.
Faculty of Chemistry and Biochemistry, Analytical Chemistry II, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801, Bochum, Germany.
Angew Chem Int Ed Engl. 2021 Sep 20;60(39):21396-21403. doi: 10.1002/anie.202106790. Epub 2021 Aug 25.
The effect of surface orientations on the formation of iridium oxide species during the oxygen evolution reaction (OER) remains yet unknown. Herein, we use a needle-shaped iridium atom probe specimen as a nanosized working electrode to ascertain the role of the surface orientations in the formation of oxide species during OER. At the beginning of electrolysis, the top 2-3 nm of (024), (026), (113), and (115) planes are covered by IrO-OH, which activates all surfaces towards OER. A thick subsurface oxide layer consisting of sub-stoichiometric Ir-O species is formed on the open (024) planes as OER proceeds. Such metastable Ir-O species are thought to provide an additional contribution to the OER activity. Overall, this study sheds light on the importance of the morphological effects of iridium electrocatalysts for OER. It also provides an innovative approach that can directly reveal surface species on electrocatalysts at atomic scale.
表面取向对析氧反应（OER）过程中氧化铱物种形成的影响尚不清楚。在此，我们使用针状铱原子探针样品作为纳米尺寸的工作电极，以确定表面取向在OER过程中氧化物物种形成中的作用。在电解开始时，（024）、（026）、（113）和（115）平面的顶部2-3nm被IrO-OH覆盖，这使所有表面都对OER具有活性。随着OER的进行，在开放的（024）平面上形成了由亚化学计量的Ir-O物种组成的厚次表面氧化层。这种亚稳态的Ir-O物种被认为对OER活性有额外贡献。总体而言，这项研究揭示了铱电催化剂形态效应对于OER的重要性。它还提供了一种创新方法，能够在原子尺度上直接揭示电催化剂上的表面物种。
