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An Oxygen-Insensitive Hydrogen Evolution Catalyst Coated by a Molybdenum-Based Layer for Overall Water Splitting
Angel T Garcia-Esparza1, Tatsuya Shinagawa1, Samy Ould-Chikh1
1KAUST Catalysis Center (KCC) and Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
Angewandte Chemie (International Ed. in English)
|April 14, 2017
Summary
This study presents an acid-tolerant electrocatalyst with a molybdenum (Mo) coating on platinum (Pt) that selectively produces hydrogen (H2) during water splitting, even with oxygen (O2) present.
Area of Science:
- Materials Science
- Electrochemistry
- Catalysis
Background:
- Efficient overall water-splitting systems require oxygen (O2)-insensitive cathodes for simultaneous hydrogen (H2) and O2 generation.
- Existing catalysts often suffer from deactivation due to O2 presence, hindering efficient H2 production.
Purpose of the Study:
- To develop an acid-tolerant electrocatalyst capable of selective H2 evolution in the presence of O2.
- To investigate the mechanism of O2 insensitivity and stability of the developed catalyst.
Main Methods:
- Coating a metal surface with molybdenum (Mo) to create an O2-insensitive cathode.
- Utilizing in-situ X-ray absorption spectroscopy to characterize the catalyst structure.
- Testing the catalyst in photocatalytic overall water splitting using MoOx/Pt/SrTiO3.
Main Results:
- A reduced platinum (Pt) surface coated with amorphous molybdenum oxyhydroxide hydrate was identified.
- The Mo coating effectively hindered O2 permeation, preventing contact with active Pt sites.
- Photocatalytic water splitting demonstrated inhibited back-reaction (water formation) with the Mo-coated catalyst.
Conclusions:
- The Mo-coated electrocatalyst demonstrates excellent acid tolerance and stability for prolonged water splitting.
- This Mo-coating strategy enables selective H2 evolution in the presence of O2, crucial for efficient water-splitting systems.