ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

The effect of the H₂:N₂ pre-treatment and reactant ratio upon the ammonia synthesis performance of the Ni₂Mo₃N catalyst

Mustafa Y. Aslan, Angela Daisley, and Justin S. J. Hargreaves

School of Chemistry, Joseph Black Building, University of Glasgow, Glasgow, UK

E-mail: mustafa.aslan@usak.edu.tr

Received: 17 December 2024  Accepted: 17 March 2025

Abstract:

The ammonia synthesis reaction over Ni₂Mo₃N was carried out at 400 °C and atmospheric pressure. The effects of the H₂:N₂ ratio on both nitridation and the ammonia synthesis reaction steps were investigated. Analysis of Ni₂Mo₃N samples nitrided at different H₂:N₂ ratios was performed using XRD and elemental analysis. The surface characteristics of Ni₂Mo₃N were determined using H₂-TPR. When Ni₂Mo₃N was nitrided under 3:1 H₂:N₂, it was observed that a lower hydrogen ratio of 0.5:1 H₂:N₂ during the catalytic test improved the performance slightly. It is believed that the H₂ poisoning effect decreases at lower H₂:N₂ ratios. The highest ammonia synthesis activity was observed over a Ni₂Mo₃N catalyst when nitrided under 0.5:1 H₂:N₂ when ammonia synthesis reaction was performed using a 3:1 H₂:N₂ reaction mixture. The reason can be the presence of metallic Ni in the catalyst structure, which is believed to facilitate H₂ spillover to reaction medium.

Keywords: Catalyst Synthesis; Catalytic Materials; Chemical Engineering; Chemical Synthesis; Inorganic Chemistry; Materials for Energy and Catalysis; Ammonia synthesis; Ternary nitrides; Ni2Mo3N

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04020-9

Chemical Papers 79 (6) 3633–3642 (2025)