Highly Durable Ni-Cu-Mo Catalyst: Preparation and Performance for Hydrogen Evolution through Ammonia Oxidation Reaction

doi:10.15541/jim20250384

Abstract

Abstract:

Developing low-cost, highly active, and durable electrocatalysts for the ammonia oxidation reaction (AOR) is pivotal for enhancing the overall efficiency of ammonia-to-hydrogen conversion technologies. In this work, a monolithic Ni-Cu-Mo electrocatalyst featuring a hierarchical nanoflower architecture was in-situ constructed on a nickel foam (NF) substrate which was both the support and nickel source via a facile one-step hydrothermal method. The integrated electrode was directly applied to ammonia-to-hydrogen production. Experimental results demonstrate that the Ni-Cu-Mo catalyst exhibits exceptional electrocatalytic activity, achieving a low onset potential of 1.32 V (vs. RHE)@10 mA·cm^-2. Furthermore, it maintains a stable current density exceeding 100 mA·cm^-2 for 64 h of continuous operation at 1.5 V (vs. RHE), showcasing outstanding potential for industrial applications. Mechanistic insights reveal that the morphology of hierarchical nanoflower induced by Mo-doping provides ample exposure of active sites, while the three-dimensional NF scaffold ensures efficient charge transport and enhances mechanical and chemical stability during the electrolysis process. Simultaneously, the electronic interaction between Ni and Cu significantly accelerates the AOR reaction kinetics. This study presents a novel self-supported Ni-Cu-Mo electrocatalyst as a robust material platform for efficient ammonia-based hydrogen production and provides innovative strategies for designing electrocatalytic systems for ammonia-hydrogen blended zero-carbon fuels in the future.

Key words: ammonia oxidation, electrocatalysis, nanocomposite, ammonia-hydrogen blended zero-carbon fuel, long-term stability

CLC Number:

O643

LI Zhijie, WANG Xiaoyang, MU Xiaojiang, ZHU Sijing, MIAO Lei. Highly Durable Ni-Cu-Mo Catalyst: Preparation and Performance for Hydrogen Evolution through Ammonia Oxidation Reaction[J]. Journal of Inorganic Materials, 2026, 41(9): 1247-1254.

Figures/Tables 16

Fig. 1 Schematic diagram of preparation processes of catalysts

Fig. 2 XRD patterns of Ni-Cu-Mo, Ni-Mo and Ni-Cu

Fig. 3 SEM images of Ni-Cu-Mo catalyst

Fig. 4 (a, b) TEM images and (c-f) EDS elemental mappings of Ni-Cu-Mo

Fig. 5 XPS spectra of Ni-Cu-Mo electrode (a) Ni2p; (b) Cu2p; (c) Mo3d; (d) O1s

Fig. 6 (a) LSV curves of Ni-Cu-Mo electrode at different ammonia concentrations; (b) CV curves and (c) LSV curves of Ni-Cu-Mo, Ni-Cu, Ni-Mo and NF Colorful figures are available on website

Fig. 7 (a) Tafel slopes of Ni-Cu-Mo, Ni-Cu, Ni-Mo and NF; (b) EIS spectra with inset showing equivalent circuit and (c) Cdl results of Ni-Cu-Mo, Ni-Cu and Ni-Mo

Fig. 8 GC analysis of AOR gas collected by three-electrode system at (a, b) 1.5 and (c, d) 1.6 V (vs. RHE)

Fig. 9 (a) i-t curve of Ni-Cu-Mo; (b) Stability compared with reported catalysts[15,25,39-47]

Fig. S1 SEM images of Ni-Cu catalysts at different magnifications

Fig. S2 SEM images of Ni-Mo catalysts at different magnifications

Fig. S3 CV curves collected at different scanning speeds using (a) Ni-Cu-Mo, (b) Ni-Cu and (c) Ni-Mo

Fig. S4 i-t curves of (a) Ni-Cu and (b) Ni-Mo

Table S1 Changes in the valence state ratios of Ni-Cu-Mo and Ni-Cu catalysts before and after 64 h i-t test

	Ni-Cu-Mo				Ni-Cu
	Cu(+2)	Cu(0)	Ni(+2)	Mo(+6)	Cu(+2)	Cu(0)	Ni(+2)	Mo(+6)
Before	28.38%	71.62%	100%	100%	21.05%	78.95%	100%	-
After	0	100%	100%	100%	82.85%	17.15%	100%	-

Fig. S5 XPS spectra of Ni-Cu-Mo catalyst after 64 h i-t test

Fig. S6 XPS spectra of Ni-Cu electrode before and after 64 h i-t test (a, d) Ni2p; (b, e) Cu2p; (c, f) O1s

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