Nickel foam-supported nickel-cobalt layered double hydroxide/platinum composite electrocatalyst for ammonia oxidation reaction

Abstract

With increasing interest in direct ammonia fuel cells, designing and developing high-activity electrocatalysts for the electrochemical ammonia oxidation reaction has become a critical research focus. In this work, a nickel foam-supported nickel-cobalt layered double hydroxide/platinum composite (Pt-NiCo-LDH) was synthesized through electrochemical deposition and displacement reactions for enhanced electrocatalytic activity. Key synthesis parameters, including reaction temperature and chloroplatinic acid hexahydrate (H₂PtCl₆.6H₂O) concentration, were systematically optimized. Electrochemical characterization using cyclic voltammetry revealed that the optimal catalyst - synthesized in a solution containing 450 μL deionized water and 1,050 μL 0.1 moL/L H₂PtCl₆·6H₂O at 20°C for 8 h - showed an oxidation peak current of 154.60 mA and a low onset potential of −0.38 V (versus mercury/mercury oxide), indicating exceptional catalytic activity. The support of nickel foam provided favorable conditions to deposit NiCo-LDH nanowires, providing sites for the growth of platinum nanoparticles, thus promoting the catalytic activity of the Pt-(NiCo-LDH) electrocatalyst.

Keywords

Electrocatalyst / Ammonia oxidation reaction / Nanocomposite / Platinum / Nickel-cobalt layered double hydroxide

Funding

This work was supported by the Innovation Training Program for College Students of Bohai University (202410167039).

Conflict of interest

The authors declare that they have no competing interests.

References

[1] Wang YJ, Wang R, Tanaka K, et al. Global spatiotemporal optimization of photovoltaic and wind power to achieve the Paris agreement targets. Nat Commun. 2025; 16(1):2127. doi: 10.1038/s41467-025-57292-w

[2] Wuttke A, Bagger A. Predicting electrocatalytic urea synthesis using a two-dimensional descriptor. Commun Chem. 2025; 8(1):30. doi: 10.1038/s42004-025-01424-2

[3] Shen Y, Fang N, Liu X, et al. Observation of metal-organic interphase in cu-based electrochemical co₂-to-ethanol conversion. Nat Commun. 2025; 16:2073. doi: 10.1038/s41467-025-57221-x

[4] Liu B, Meng K, Cheng B, Wang L, Liang G, Bie C. Prolonging charge carrier lifetime in s-scheme heterojunctions via ligand-to-metal charge transfer of Ni-MOF for photocatalytic H₂ production and simultaneous benzylamine coupling. J Mater Sci Technol. 2025; 231:286-295. doi: 10.1016/j.jmst.2025.02.013

[5] Ju C, Li K, Xu C, Bao F. Challenges and opportunities of hydrogen energy application in public transportation in the post-epidemic period. Humanit Soc Sci Commun. 2025; 12:283. doi: 10.1057/s41599-024-04089-9

[6] Wu S, Jiang Y, Luo W, et al. Ag-Co3O4-CoOOH-nanowires tandem catalyst for efficient electrocatalytic conversion of nitrate to ammonia at low overpotential via triple reactions. Adv Sci. 2023; 10(33):e2303789. doi: 10.1002/advs.202303789

[7] Ya Y, Xu YS, Elbanna AM, Liu Y, Sun B, Cheng X. Review of direct ammonia solid oxide fuel cells: Low temperature cell structure and ammonia decomposition strategies. Renew Sustain Energy Rev. 2025; 213:115350. doi: 10.1016/j.rser.2025.115350

[8] Gong Z, Wang H, Li C, et al. Progress in the design and performance evaluation of catalysts for low-temperature direct ammonia fuel cells. Green Chem Eng. 2025; 6:54-67. doi: 10.1016/j.gce.2024.06.001

[9] Zhang C, Hwanga SY, Peng Z. Shape-enhanced ammonia electro-oxidation property of a cubic platinum nanocrystalcatalyst prepared by surfactant-free synthesis. J Mater Chem A. 2013; 1:14402-14408. doi: 10.1039/c3ta13641h

[10] Zhong C, Hu WB, Cheng YF. On the essential role of current density in electrocatalytic activity of the electrodeposited platinum for oxidation of ammonia. J Power Sources. 2011; 196:8064-8072. doi: 10.1016/j.jpowsour.2011.05.058

[11] Liu J, Chen B, Kou Y, et al. Pt-decorated highly porous flower-like ni particles with high mass activity for ammonia electro-oxidation. J Mater Chem A. 2016; 4:11060-11068. doi: 10.1039/c6ta02284g

[12] Vooys ACAD, Koper MTM, Santen RA, Veen JARV. The role of adsorbates in the electrochemical oxidation of ammonia on noble and transition metal electrodes. J Electroanal Chem. 2001; 506:127-137. doi: 10.1016/S0022-0728(01)00491-0

[13] Katayama Y, Okanishi T, Muroyama H, Matsui T, Eguchi K. Enhancement of ammonia oxidation activity over Y2O3-modified platinum surface: Promotion of NH₂,ad dimerization process. J Cat. 2016; 344:496-506. doi: 10.1016/j.jcat.2016.10.020

[14] Okanishi T, Katayama Y, Muroyama H, Matsui T, Eguchi K. SnO2-modified pt electrocatalysts for ammonia-fueled anion exchange membrane fuel cells. Electrochim Acta. 2015; 173:364-369. doi: 10.1016/j.electacta.2015.05.066

[15] Katayama Y, Okanishi T, Muroyama H, Matsui T, Eguchi K. Electrochemical oxidation of ammonia over rare earth oxide modified platinum catalysts. J Phys Chem C. 2015; 119:9134-9141. doi: 10.1021/acs.jpcc.5b01710

[16] Zhang HM, Wang YF, Kwok YH, Wu ZC, Xia DH, Leung DYC. A direct ammonia microfluidic fuel cell using nicu nanoparticles supported on carbon nanotubes as an electrocatalyst. Chemsuschem. 2018; 11:2889-2897. doi: 10.1002/cssc.201801232

[17] Jin Y, Liu Y, Wu RY, Wang J. Local tensile strain boosts the electrocatalytic ammonia oxidation reaction. Chem Commun. 2024; 60:1104-1107. doi: 10.1039/d3cc04820a

[18] Zhang H, Chen W, Wang H, et al. A core-shell NiCu@NiCuOOH 3D electrode induced by surface electrochemical reconstruction for the ammonia oxidation reaction. Int J Hydrogen Energy. 2022; 47:16080-16091. doi: 10.1016/j.ijhydene.2022.03.139

[19] Zhu M, Yang Y, Xi S, et al. Deciphering NH3 adsorption kinetics in ternary Ni-Cu-Fe oxyhydroxide toward efficient ammonia oxidation reaction. Small. 2021; 17:e2005616. doi: 10.1002/smll.202005616

[20] Ren S, Duan D, Wu Y, Zhang H, Ge X. One-step fabrication of free-standing copper/nickel composites for efficient electrocatalytic ammonia oxidation by bimetallic synergistic effect. Mater Today Commun. 2025; 42:111120. doi: 10.1016/j.mtcomm.2024.111120

[21] Wang J, Qing S, Tong X, et al. Boron nanoclusters endowed nife layered double hydroxides with efficient bifunction toward ammonia oxidation reaction and hydrogen evolution reaction. Appl Surf Sci. 2023; 640:158330. doi: 10.1016/j.apsusc.2023.158330

[22] Han Y, Zhang L, Gu J, Qian J, Wang X. Dual performing PtNi alloys nanosheets for electrocatalytic ammonia oxidation reaction and electrochemical detection of ammonia-nitrogen. J Alloys Compd. 2025; 1010:177286. doi: 10.1016/j.jallcom.2024.177286

[23] Yu T, Liu G, Nie T, et al. Pt-loaded cofe-layered double hydroxides for simultaneously driving HER and HzOR. ACS Cat. 2024; 14:14937-14946. doi: 10.1021/acscatal.4c03881

[24] Lin X, Zhang X, Wang Z, et al, Hyperbranched concave octahedron of PtIrCu nanocrystals with high-index facets for efficiently electrochemical ammonia oxidation reaction. J Colloid Interface Sci. 2021; 601:1-11. doi: 10.1016/j.jcis.2021.04.068

[25] Zhang S, Hu J, Li SFY, et al. Electrochemical sensing mechanism of ammonium ions over an Ag/TiO₂ composite electrode modified by hematite. Chem Commun. 2023; 59:2636-2639. doi: 10.1039/d3cc00240c

[26] Zhang L, Cai H, Han Y, et al. Achieving hierarchical Co(OH)₂ nanosheets and Pt nanospheres for high-performance electrochemical detection of ammonia-nitrogen. Microchem J. 2025; 208:112478. doi: 10.1016/j.microc.2024.112478

[27] Zhang H, Wang H, Tong X, et al. Sulfur induced surface reconfiguration of Ni1Cu3-S-T/CP anode for high-efficiency ammonia electro-oxidation. Chem Eng J. 2023; 452:139582. doi: 10.1016/j.cej.2022.139582

[28] Fang H, Liao C, Cai Q, et al. Tuning surficial atomic configuration of Pt-Ir catalysts for efficient ammonia oxidation and low-temperature direct ammonia fuel cells. Chem Eng Sci. 2023; 280:118836. doi: 10.1016/j.ces.2023.118836

[29] Zhang L, Yuan M, Wang X, Gu J. Enhanced electrocatalytic oxidation activity of platinum-poly(methylene blue) as a sensitive sensor for ammonia-nitrogen detection. Microchem J. 2024; 199:110238. doi: 10.1016/j.microc.2024.110238

[30] Zhang L, Ma X, Liu J, et al. Achieving Ni@(Pt/Ni(OH)2) ternary nanoflowers derived from ni nanoflowers for electrochemical ammonia-nitrogen detection in the aqueous environment. Microchem J. 2024; 200:110401. doi: 10.1016/j.microc.2024.110401

[31] Wang X, Gong Y, Cai H, et al. Fabrication of platinum-decorated NiCo-layered double hydroxide nanoflowers for electrocatalytic ammonia oxidation reaction. Catalysts. 2024; 14(9):559. doi: 10.3390/catal14090559