The lattice oxygen mechanism (LOM) is considered one of the promising approaches to overcome the sluggish oxygen evolution reaction (OER), bypassing -OOH* coordination with a high energetic barrier. Activated lattice oxygen can participate in the OER as a reactant and enables O*-O* coupling for direct O2 formation. However, such reaction kinetics inevitably include the generation of oxygen vacancies, which leads to structural degradation, and eventually shortens the lifetime of catalysts. Here, we demonstrate that Se incorporation significantly enhances OER performance and the stability of NiFe (oxy)hydroxide (NiFe) which follows the LOM pathway. In Se introduced NiFe (NiFeSe), Se forms not only metal-Se bonding but also Se-oxygen bonding by replacing oxygen sites and metal sites, respectively. As a result, transition metals show reduced valence states while oxygen shows less reduced valence states (O-/O2 2-) which is a clear evidence of lattice oxygen activation. By virtue of its electronic structure modulation, NiFeSe shows enhanced OER activity and long-term stability with robust active lattice oxygen compared to NiFe.

Abstract
1. Introduction
2. Experimental
    2.1. 용액의 준비
    2.2. 전기화학 증착
    2.3. 소재 분석
    2.4. 전기화학 평가
3. Results and discussion
4. Conclusions
References

• 조승환(동국대학교 물리반도체과학부 학생) | Seunghwan Jo (Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea)
• 손정인(동국대학교 물리반도체과학부 교수) | Jung Inn Sohn (Division of Physics and Semiconductor Science, Dongguk University, Seoul 04620, Republic of Korea) Corresponding author