title: Amorphous Cobalt Phyllosilicate with Layered Crystalline Motifs as Water Oxidation Catalyst.
abstract: The development of a high-performance oxygen evolution reaction (OER) catalyst is pivotal for the practical realization of a water-splitting system. Although an extensive search for OER catalysts has been performed in the past decades, cost-effective catalysts remain elusive. Herein, an amorphous cobalt phyllosilicate (ACP) with layered crystalline motif prepared by a room-temperature precipitation is introduced as a new OER catalyst; this material exhibits a remarkably low overpotential (η ≈ 367 mV for a current density of 10 mA cm-2). A structural investigation using X-ray absorption spectroscopy reveals that the amorphous structure contains layered motifs similar to the structure of CoOOH, which is demonstrated to be responsible for the OER catalysis based on density functional theory calculations. However, the calculations also reveal that the local environment of the active site in the layered crystalline motif in the ACP is significantly modulated by the silicate, leading to a substantial reduction of η of the OER compared with that of CoOOH. This work proposes amorphous phyllosilicates as a new group of efficient OER catalysts and suggests that tuning of the catalytic activity by introducing redox-inert groups may be a new unexplored avenue for the design of novel high-performance catalysts.
authors.affiliation: Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.
authors.forename: Ju Seong
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.
authors.forename: Inchul
authors.initials: I
authors.lastname: Park
authors.affiliation: Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.
authors.forename: Eun-Suk
authors.initials: ES
authors.lastname: Jeong
authors.affiliation: Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.
authors.forename: Kyoungsuk
authors.initials: K
authors.lastname: Jin
authors.affiliation: Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.
authors.forename: Won Mo
authors.initials: WM
authors.lastname: Seong
authors.affiliation: Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.
authors.forename: Gabin
authors.initials: G
authors.lastname: Yoon
authors.affiliation: Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.
authors.forename: Hyunah
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.
authors.forename: Byunghoon
authors.initials: B
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.
authors.forename: Ki Tae
authors.initials: KT
authors.lastname: Nam
authors.affiliation: Department of Materials Science and Engineering, Research Institute of Advanced Materials (RIAM), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.|Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Republic of Korea.
authors.forename: Kisuk
authors.initials: K
authors.lastname: Kang
keywords: electrocatalyst; layered (oxy)hydroxides; oxygen evolution reaction; phyllosilicate; water splitting