Tuning Bifunctional Oxygen Electrocatalysts by Changing the A‐Site Rare‐Earth Element in Perovskite Nickelates

• DOI: 10.1002/adfm.201803712
• Publication Date: 2018-08-07T10:35:53Z
• Authors: Le Wang; Kelsey A. Stoerzi...; Lei Chang; Jiali Zhao; Yangyang Li; Chi Sin Tang; Xinmao Yin; Mark E. Bowden; Zhenzhong Yang; Haizhong Guo; Lu You; Rui Guo; Jiaou Wang; Kurash Ibrahim; Jingsheng Chen; Andrivo Rusydi; Junling Wang; Scott A. Chambers; Yingge Du
• Keywords: Oxygen evolution; Ionic radius; Sodalite

Abstract Perovskite‐structured (ABO 3 ) transition metal oxides are promising bifunctional electrocatalysts for efficient oxygen evolution reaction (OER) and reduction (ORR). In this paper, a set of epitaxial rare‐earth nickelates (RNiO thin films is investigated with controlled A‐site isovalent substitution to correlate their structure physical properties ORR/OER activities, examined by using three‐electrode system in O 2 ‐saturated 0.1 m KOH electrolyte. The ORR activity decreases monotonically decreasing the element ionic radius which lowers conductivity RNiO (R = La, La 0.5 Nd , 0.2 0.8 Nd, Sm Sm, Gd) films, LaNiO being most conductive active. On other hand, OER initially increases upon substituting maximal at NiO . Moreover, remains comparable within error through Sm‐doped NdNiO Beyond that, cannot be measured due potential voltage drop across film. improved ascribed partial Ni 3+ 2+ as result vacancies, average occupancy e g antibonding orbital more than one. work highlights importance tuning elements an effective strategy balancing activities electrocatalysts.