Structural Insights into Multi‐Metal Spinel Oxide Nanoparticles for Boosting Oxygen Reduction Electrocatalysis

Abstract

Multi‐metal oxide (MMO) materials have significant potential to facilitate various demanding reactions by providing additional degrees of freedom in catalyst design. However, a fundamental understanding of the (electro)catalytic activity of MMOs is limited because of the intrinsic complexity of their multi‐element nature. Additional complexities arise when MMO catalysts have crystalline structures with two different metal site occupancies, such as the spinel structure, which makes it more challenging to investigate the origin of the (electro)catalytic activity of MMOs. Here, uniform‐sized multi‐metal spinel oxide nanoparticles composed of Mn, Co, and Fe as model MMO electrocatalysts are synthesized and the contributions of each element to the structural flexibility of the spinel oxides are systematically studied, which boosts the electrocatalytic oxygen reduction reaction (ORR) activity. Detailed crystal and electronic structure characterizations combined with electrochemical and computational studies reveal that the incorporation of Co not only increases the preferential octahedral site occupancy, but also modifies the electronic state of the ORR‐active Mn site to enhance the intrinsic ORR activity. As a result, nanoparticles of the optimized catalyst, Co0.25Mn0.75Fe2.0‐MMO, exhibit a half‐wave potential of 0.904 V (versus RHE) and mass activity of 46.9 A goxide−1 (at 0.9 V versus RHE) with promising stability.

Understanding and application of metal–support interactions in catalysts for CO-PROX

“…However, when it comes to the in-depth mechanisms of reaction, the NPCs system is often more complex than the corresponding SACs and NCCs. The catalytic behavior of supported metal nanoparticles is governed by many parameters such as particle size, 84 nanostructure, 85 interface, 86 structural flexibility 87 and MSI, 88 and sometimes the final performance may be a result of the synergisitic effect of several factors. Herein, the vital role of MSI is primarily discussed.…”

Computation and Machine Learning for Catalyst Discovery

“…[7] 은 백금 기반 합금에 대한 계산 결과, 최적의 흡착에너지를 갖는 촉매 (Pt 3 Ni, Pt 3 Co)를 계산화학적으로 제안하였고 실험으로 검증하였다. 이 밖에도, 코어/쉘 구조 형태의 나노 입자 [8] 혹은 스피넬 산화물 [9,10] 등 다양한 형태의 ORR 촉매 가 연구되고 있다 [11,12] . 다 [17].…”

Porous spinel-type transition metal oxide nanostructures as emergent electrocatalysts for oxygen reduction reactions

“…, nanocubes and polyhedral), have been developed for ORRs. 21–27,32 Thus, spinel-type TMO nanocatalysts have attracted significant attention for various electrocatalytic applications. Mainly, ∼307 articles were published in the last 10 years and cited 10 387 times (33.8 citations per article, Fig.…”

“…Numerous spinel-type TMO nanocatalysts with distinct morphologies, including but not limited to 1D (i.e., nanoneedles, nanowires, and nanorods), 2D (i.e., nanosheets and flakes), and multi-dimensional (i.e., nanocubes and polyhedral), have been developed for ORRs. [21][22][23][24][25][26][27]32 Thus, spinel-type TMO nanocatalysts have attracted significant attention for various electrocatalytic applications. Mainly, ∼307 articles were published in the last 10 years and cited 10 387 times (33.8 citations per article, Fig.…”