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The Effect of Fe and Co Additions on the Efficiency of NiOOH Catalyst Under Strain
Author(s) -
Hamal Ester Korkus,
Toroker Maytal Caspary
Publication year - 2020
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201902289
Subject(s) - water splitting , catalysis , oxygen evolution , electrocatalyst , doping , density functional theory , valence (chemistry) , nickel , materials science , deprotonation , chemical engineering , oxygen , inorganic chemistry , chemistry , computational chemistry , electrochemistry , metallurgy , electrode , optoelectronics , photocatalysis , ion , biochemistry , organic chemistry , engineering
The major limitation of using water splitting for generating hydrogen fuel is the lack of efficient catalysts for the oxygen evolution reaction (OER). A commonly used catalyst for OER is Nickel oxyhydroxide (NiOOH), but pure NiOOH has poor efficiency unless doped with Fe and Co. We explore the influence of co‐doping on the efficiency of NiOOH in the process of water oxidation by using Density Functional Theory +U (DFT+U). We also test the effect of strain on catalytic efficiency by modeling water oxidation on expanded and contracted surfaces of NiFeCoOOH. We find that several doping locations of Co have a similar result as if NiFeOOH had no Co content. Iron is responsible for the high activity at the Fe active site due to the low energy required for charge extraction. Yet, the valence band edge includes Fe, Co and Ni states hybridized which allows better charge extraction during deprotonation. The valence band edge position is higher upon Co‐doping, which should allow better hole transport toward the surface. Hence, the presence of Ni and Co atoms surrounding the active site is vital for better efficiency. Moreover, we found that applying strain does not improve the efficiency and therefore a substrate with minimal mismatch should be used for NiFeCoOOH electrocatalysis.