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Vertically aligned Ni/NiO nanocomposites with abundant oxygen deficient hetero-interfaces for enhanced overall water splitting

DOI: 10.1007/s11426-022-1326-2 DOI Help

Authors: Hongxia Wang (Xiamen University) , Meiyan Cui (Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences) , Gaoliang Fu (Xiamen University; Huanghe Science and Technology College) , Jiaye Zhang (Xiamen University) , Xingyu Ding (Xiamen University) , Irene Azaceta (University of York) , Matthew Bugnet (SuperSTEM Laboratory; Univeristy of Leeds; Univ Lyon, CNRS, INSA Lyon, UCBL, MATEIS, UMR 5510) , Demie M. Kepaptsoglou (University of York; SuperSTEM Laboratory) , Vlado K. Lazarov (University of York) , Víctor A. De La Pena O'Shea (IMDEA Energy Institute) , Freddy E. Oropeza (IMDEA Energy Institute) , Kelvin H. L. Zhang (Xiamen University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Science China Chemistry , VOL 16

State: Published (Approved)
Published: September 2022

Abstract: The design of heterostructured transition metal-based electrocatalysts with controlled composition and interfaces is key to increasing the efficiency of the water electrolysis and the elucidation of reaction mechanisms. In this work, we report the synthesis of well-controlled vertically aligned Ni/NiO nanocomposites consisting of Ni nanoclusters embedded in NiO, which result in highly efficient electrocatalysts for overall water splitting. We show that such a high catalytic efficiency toward both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) originates from a synergetic effect at Ni/NiO interfaces that significantly reduces the energy barrier for water dissociation, and favours the formation of reactive H* intermediates on the Ni side of the interface, and OHads on the NiO side of the interface. A study of water chemisorption based on near-ambient pressure photoelectron spectroscopy indicates that the abundant hetero-interfaces in Ni/NiO nanocomposite promote the dissociation of water with a three-fold increase in the surface concentration of OHads compared with pure NiO. Density functional theory calculations indicate that Ni/NiO interface leads to the reduction of the water dissociation energy barrier due to a high concentration of oxygen vacancies at NiO side of the interface, whereas the formation of highly active metallic Ni sites with an optimal value of Gibbs free energy of H* (ΔGH* = −0.16 eV) owes to a favourable adjustment of the electron energetics at the interface, thus accelerating the overall electrochemical water splitting.

Journal Keywords: water splitting; hydrogen evolution reaction; electronic structure; heterostructure; vertically aligned nanocomposites

Subject Areas: Chemistry, Physics, Materials

Instruments: I09-Surface and Interface Structural Analysis

Other Facilities: XAFCA beamline at Singapore Synchrotron Light Source (SSLS)

Added On: 26/09/2022 13:11

Discipline Tags:

Surfaces Physics Physical Chemistry Catalysis Chemistry Materials Science interfaces and thin films Nanoscience/Nanotechnology

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS)