An Oxygen-Insensitive Hydrogen Evolution Catalyst Coated by a Molybdenum-Based Layer for Overall Water Splitting

Angel T Garcia-Esparza; Tatsuya Shinagawa; Samy Ould-Chikh; Muhammad Qureshi; Xuyuan Peng; Nini Wei; Dalaver H Anjum; Alain Clo; Tsu-Chien Weng; Dennis Nordlund; Dimosthenis Sokaras; Jun Kubota; Kazunari Domen; Kazuhiro Takanabe

doi:10.1002/anie.201701861

An Oxygen-Insensitive Hydrogen Evolution Catalyst Coated by a Molybdenum-Based Layer for Overall Water Splitting

Angew Chem Int Ed Engl. 2017 May 15;56(21):5780-5784. doi: 10.1002/anie.201701861. Epub 2017 Apr 13.

Authors

Affiliations

¹ KAUST Catalysis Center (KCC) and Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
² Advanced Nanofabrication, Imaging and Characterization Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
³ Research Computing, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
⁴ Center for High Pressure Science & Technology Advanced Research, 1690 Cailun Rd, Bldg. #6-408, Pudong, Shanghai, 201203, China.
⁵ Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.
⁶ Department of Chemical Engineering, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan.
⁷ Department of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.

PMID: 28407339
DOI: 10.1002/anie.201701861

Abstract

For overall water-splitting systems, it is essential to establish O₂ -insensitive cathodes that allow cogeneration of H₂ and O₂ . An acid-tolerant electrocatalyst is described, which employs a Mo-coating on a metal surface to achieve selective H₂ evolution in the presence of O₂ . In operando X-ray absorption spectroscopy identified reduced Pt covered with an amorphous molybdenum oxyhydroxide hydrate with a local structural order composed of polyanionic trimeric units of molybdenum(IV). The Mo layer likely hinders O₂ gas permeation, impeding contact with active Pt. Photocatalytic overall water splitting proceeded using MoO_x /Pt/SrTiO₃ with inhibited water formation from H₂ and O₂ , which is the prevailing back reaction on the bare Pt/SrTiO₃ photocatalyst. The Mo coating was stable in acidic media for multiple hours of overall water splitting by membraneless electrolysis and photocatalysis.

Keywords: electrocatalysis; hydrogen evolution; in operando XAS; photocatalysis; water splitting.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't