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Updated: Sep 18, 2025
07:47
Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles
Published on: November 27, 2015
11.0K
Surface Oxidation of Transition Metal Nitrides
Ji Liu1, Jean-Pierre Glauber2,3, Julian Lorenz4
1Tyndall National Institute, University College Cork, Lee Maltings, Dyke Parade, Cork T12 R5CP, Ireland.
Summary
Transition metal nitrides offer a path to efficient ammonia synthesis. This study reveals ZrN and VN exhibit different oxidation behaviors under ambient conditions, impacting their use in electrocatalysis.
Area of Science:
- Materials Science
- Electrochemistry
- Catalysis
Background:
- The Haber-Bosch process for ammonia (NH3) production is energy-intensive and produces CO2.
- Electrochemical ammonia synthesis is a promising alternative, but limited by the sluggish nitrogen reduction reaction (NRR).
- Transition metal nitrides (TMNs) show potential for NRR electrocatalysis due to their nitrogen-rich surfaces.
Purpose of the Study:
- To investigate the unintentional oxidation of Zirconium Nitride (ZrN) and Vanadium Nitride (VN) surfaces.
- To understand the atomic-scale mechanisms of oxidation at various temperatures (295 K to 1023 K).
- To correlate oxidation behavior with the suitability of TMNs for NRR electrocatalysis.
Main Methods:
- Ab initio molecular dynamics (aiMD) simulations were used to model oxidation processes.
- Experimental validation using Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA) on MOCVD-deposited nitride films.
- Analysis of surface and bulk oxidation at different temperatures under ambient oxygen conditions.
Main Results:
- ZrN surfaces form oxynitrides at lower temperatures and a ZrOx/ZrN interface at higher temperatures.
- VN(111) surfaces form VOx clusters, with limited oxygen migration into the bulk.
- ZrN exhibits more significant oxidation than VN due to differences in V-N/O and Zr-O/N bond strengths and oxide stability.
Conclusions:
- The distinct oxidation pathways of ZrN and VN under ambient conditions are governed by their intrinsic bond strengths.
- ZrN's tendency to form a stable ZrO2 layer influences its oxidation profile, while VN forms less stable VOx clusters.
- Understanding these oxidation mechanisms is crucial for designing stable and efficient TMN electrocatalysts for ammonia synthesis.
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