In:
ECS Meeting Abstracts, The Electrochemical Society, Vol. MA2020-01, No. 37 ( 2020-05-01), p. 1522-1522
Abstract:
Water splitting to generate O 2 and H 2 fuel has been a major focus of (photo)electrochemical energy storage and conversion efforts, but many challenges remain. While water oxidation to generate O 2 through the oxygen evolution reaction (OER) accounts for the majority of energy loss in this process, water reduction to generate H 2 through the hydrogen evolution reaction in alkaline is over two orders of magnitude slower than that in acid. For OER, NiFe layered double hydroxides have attracted significant interest due to their comparable performance with precious metal-based RuO 2 and IrO 2 catalysts. In spite of extensive study, however, the 3D crystal structure of the active phase under catalytic oxygen evolution reaction conditions remains unclear. The lack of the atomic-scale details of crystal structure makes it challenging to choose appropriate structural models for first principles-based mechanistic studies. Therefore, it is of significant interest to identify these materials’ in-situ crystal structure and, subsequently, determine the intrinsic catalytic mechanism. Similarly, for alkaline HER, ultrathin (oxy)hydroxide films on precious metal substrates possess impressive activity improvement, but the films’ structure and stability are still largely unknown, and the catalytic mechanism remains unclear. In this presentation, we will begin by showing our recent efforts to elucidate the catalytically active phase and OER mechanism on NiFe layered double hydroxides by combining electrochemical measurements, operando experiments, DFT calculations, and ab initio molecular dynamics simulations. Next, for HER, we will introduce the methodologies we have recently developed towards the highly accurate prediction of Pourbaix diagram of transition metal (oxy)hydroxides. Subsequently, using monolayer Ni (oxy)hydroxide films as an example, we will describe a simple scheme to study the structures and the stability of these films on precious metal surfaces. We will show how the ultrathin films can be dramatically stabilized with respect to the corresponding bulk analogs. Then, using the hydrogen evolution reaction as an example, we will demonstrate how these techniques can be applied to understand the steady state, the active phases, and the catalytic mechanism of bi-functional interfaces. We will then demonstrate the extension of the present understanding to real-world catalysts, i.e. precious metal nanoparticles supported on ultrathin transition metal (oxy)hydroxide films. Finally, we will show this understanding can be used to design new bi-functional catalysts with improved performances. If time permits, we will also show our recent work on tunable intrinsic strain in two-dimensional transition metal electrocatalysts for the oxygen reduction reaction. References: 1. Z. Zeng, K.-C. Chang, J. Kubal, N. M. Markovic, J. Greeley, Nature Energy 2 , 17070 (2017). 2. L. Wang, Y. Zhu, Z. Zeng, C. Lin, M. Giroux, L. Jiang, Y. Han, J. Greeley, C. Wang, J. Jin, Nano Energy 31, 456-461 (2017). 3. L. Wang, Z. Zeng, W. Gao, T. Maxson, D. Raciti, M. Giroux, X. Pan, C. Wang, J. Greeley, Science 363 , 870-874 (2019). 4. F. Dionigi, Z. Zeng, I. Sinev, T. Merzdorf, S. Deshpande, M. Bernal Lopez, S. Kunze, I. Zegkinoglou, H. Sarodnik, D. Fan, A. Bergmann, J. Drnec, J. Ferreira de Araujo, M. Gliech, D. Teschner, J. Greeley, B. Roldan Cuenya, P. Strasser, submitted, 2019.
Type of Medium:
Online Resource
ISSN:
2151-2043
DOI:
10.1149/MA2020-01371522mtgabs
Language:
Unknown
Publisher:
The Electrochemical Society
Publication Date:
2020
detail.hit.zdb_id:
2438749-6
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