Pnictogenation-Driven Exsolution of Size-Tunable Ru Electrocatalysts in Conductive Matrices to Reinforce Inner-Sphere-Mechanism-Assisted Electronic Coupling

Abstract

The exsolution method has garnered significant attention owing to its high efficacy in developing highly efficient and stable metal nanocatalysts. Herein, a versatile exsolution approach is developed to embed size-tunable metal nanocatalysts within a conductive metal pnictogenide matrix. The gas-phase reaction of Ru-substituted Ni–Fe-layered-double-hydroxide (Ni₂Fe_1−xRu_x-LDH) with pnictogenation reagents leads to the exsolution of Ru metal nanocatalysts and a phase transformation into metal pnictogenide. The variation in reactivity of pnictogenation reagents allows for control over the size of the exsolved metal nanocatalysts (i.e., nanoclusters for nitridation and single atoms for phosphidation), underscoring the effectiveness of the pnictogenation-driven exsolution strategy in stabilizing size-tunable metal nanocatalysts. The Ru-exsolved nickel–iron nitride/phosphide demonstrates outstanding electrocatalyst activity for the hydrogen evolution reaction, exhibiting a smaller overpotential and higher stability than Ru-deposited homologs. The high efficacy of pnictogenation-assisted exsolution in optimizing the performance and stability of Ru metal nanocatalysts is ascribed to the efficient interfacial electronic interaction between Ru metals and nitride/phosphide ions assisted by the inner sphere mechanism. In situ spectroscopic analyses highlight that exsolved Ru single atoms facilitate more efficient electron transfer to the reactants than the exsolved Ru nanoclusters, which is primarily responsible for the superior impact of the phosphidation-driven exsolution approach.

Keywords

electrocatalyst / inner sphere mechanism / metal pnictogenide matrix / pnictogenation-driven exsolution / size-tunable nanocatalyst

References

[1] Y. H. Kim, H. Jeong, B. -R. Won, and J. Myung, “Exsolution Modeling and Control to Improve the Catalytic Activity of Nanostructured Electrodes,” Advanced Materials 35, no. 16 (2023): 2208984.

[2] M. Ling, Y. Zhu, Y. Song, et al, “A New Durable Surface Nanoparticles-Modified Perovskite Cathode for Protonic Ceramic Fuel Cells From Selective Cation Exsolution Under Oxidizing Atmosphere,” Advanced Materials 34, no. 10 (2022): 2106379.

[3] H. Lv, L. Lin, X. Zhang, et al., “In Situ Investigation of Reversible Exsolution/Dissolution of CoFe Alloy Nanoparticles in a Co-Doped Sr₂Fe_1.5Mo_0.5O_6−δ Cathode for CO₂ Electrolysis,” Advanced Materials 32, no. 6 (2020): 1906193.

[4] D. Zubenko, S. Singh, and B. A. Rosen, “Exsolution of Re-Alloy Catalysts With Enhanced Stability for Methane Dry Reforming,” Applied Catalysis, B: Environmental 209 (2017): 711-719.

[5] B. Hua, M. Li, Y. -F. Sun, J. -H. Li, and J. -L. Luo, “Enhancing Perovskite Electrocatalysis of Solid Oxide Cells Through Controlled Exsolution of Nanoparticles,” Chemsuschem 10, no. 17 (2017): 3333-3341.

[6] J. G. Lee, J. -H. Myung, A. B. Naden, O. S. Jeon, Y. G. Shul, and J. T. S. Irvine, “Replacement of Ca by Ni in a Perovskite Titanate to Yield a Novel Perovskite Exsolution Architecture for Oxygen-Evolution Reactions,” Advanced Energy Materials 10, no. 10 (2020): 1903693.

[7] H. Lv, L. Lin, X. Zhang, et al., “Promoting Exsolution of RuFe Alloy Nanoparticles on Sr₂Fe_1.4Ru_0.1Mo_0.5O_6−δ via Repeated Redox Manipulations for CO₂ Electrolysis,” Nature Communications 12 (2021): 5665.

[8] H. Han, J. Park, S. Y. Nam, et al., “Lattice Strain-Enhanced Exsolution of Nanoparticles in Thin Films,” Nature Communications 10 (2019): 1471.

[9] D. Neagu, V. Kyriakou, I. -L. Roiban, et al., “In Situ Observation of Nanoparticle Exsolution From Perovskite Oxides: From Atomic Scale Mechanistic Insight to Nanostructure Tailoring,” ACS Nano 13, no. 11 (2019): 12996-13005.

[10] M. A. Naeem, P. M. Abdala, A. Armutlulu, S. M. Kim, A. Fedorov, and C. R. Müller, “Exsolution of Metallic Ru Nanoparticles From Defective, Fluorite-Type Solid Solutions Sm₂Ru_xCe_2−xO₇ to Impart Stability on Dry Reforming Catalysts,” ACS Catalysis 10, no. 3 (2020): 1923-1937.

[11] D. J. Deka, J. Kim, S. Gunduz, et al., “Investigation of Hetero-Phases Grown via In-Situ Exsolution on a Ni-Doped (La,Sr)FeO₃ Cathode and the Resultant Activity Enhancement in CO₂ Reduction,” Applied Catalysis, B: Environmental 286 (2021): 119917.

[12] H. Arandiyan, Y. Wang, J. Scott, S. Mesgari, H. Dai, and R. Amal, “In Situ Exsolution of Bimetallic Rh-Ni Nanoalloys: A Highly Efficient Catalyst for CO₂ Methanation,” ACS Applied Materials & Interfaces 10, no. 19 (2018): 16352-16357.

[13] H. Lv, T. Liu, X. Zhang, et al., “Atomic-Scale Insight Into Exsolution of CoFe Alloy Nanoparticles in La_0.4Sr_0.6Co_0.2Fe_0.7Mo_0.1O_3−δ With Efficient CO₂ Electrolysis,” Angewandte Chemie International Edition 59, no. 37 (2020): 15968-15973.

[14] S. Y. Yun, S. Lee, X. Jin, A. Soon, and S. -J. Hwang, “Ammonolysis-Driven Exsolution of Ru Nanoparticle Embedded in Conductive Metal Nitride Matrix to Boost Electrocatalyst Activity,” Advanced Science 11, no. 24 (2024): 2309819.

[15] D. Neagu, T. -S. Oh, D. N. Miller, et al., “Nano-Socketed Nickel Particles With Enhanced Coking Resistance Grown In Situ by Redox Exsolution,” Nature Communications 6 (2015): 8120.

[16] O. Kwon, S. Sengodan, K. Kim, et al., “Exsolution Trends and Co-Segregation Aspects of Self-Grown Catalyst Nanoparticles in Perovskites,” Nature Communications 8 (2017): 15967.

[17] G. Tsekouras, D. Neagu, and J. T. S. Irvine, “Step-Change in High Temperature Steam Electrolysis Performance of Perovskite Oxide Cathodes With Exsolution of B-Site Dopants,” Energy & Environmental Science 6 (2013): 256-266.

[18] S. Y. Yun, X. Jin, and S. -J. Hwang, “A One-Pot Carbon-Coating-Ex-Solution Route to Efficient Ru-MnO@C Nanowire Electrocatalysts With Enhanced Interfacial Interactions,” Chemical Engineering Journal 446 (2022): 136816.

[19] J. Wang, D. Kalaev, J. Yang, et al., “Fast Surface Oxygen Release Kinetics Accelerate Nanoparticle Exsolution in Perovskite Oxides,” Journal of the American Chemical Society 145, no. 3 (2023): 1714-1727.

[20] Y. -F. Sun, Y. -Q. Zhang, J. Chen, et al., “New Opportunity for In Situ Exsolution of Metallic Nanoparticles on Perovskite Parent,” Nano Letters 16, no. 8 (2016): 5303-5309.

[21] Y. Li and L. Zhang, “Synthesis of Highly Substitutional Nitrogen Doped TiO₂ via Oxygen Vacancy Mediated Strategy for Ultrafast-Charging Lithium Ion Storage,” Chemical Engineering Journal 431 (2022): 134164.

[22] X. Liu, J. -Q. Huang, Q. Zhang, and L. Mai, “Nanostructured Metal Oxides and Sulfides for Lithium−Sulfur Batteries,” Advanced Materials 29, no. 20 (2017): 1601759.

[23] H. He, D. Huang, W. Pang, et al., “Plasma-Induced Amorphous Shell and Deep Cation-Site S Doping Endow TiO₂ With Extraordinary Sodium Storage Performance,” Advanced Materials 30, no. 26 (2018): 1801013.

[24] Y. Ma, X. Xie, W. Yang, et al., “Recent Advances in Transition Metal Oxides With Different Dimensions as Electrodes for High-Performance Supercapacitors,” Advanced Composites and Hybrid Materials 4 (2021): 906-924.

[25] S. I. Shin, A. Go, I. Y. Kim, J. M. Lee, Y. Lee, and S. -J. Hwang, “A Beneficial Role of Exfoliated Layered Metal Oxide Nanosheets in Optimizing the Electrocatalytic Activity and Pore Structure of Pt-Reduced Graphene Oxide Nanocomposites,” Energy & Environmental Science 6 (2013): 608-617.

[26] M. Jiang, H. Zhai, L. Chen, et al., “Unraveling the Synergistic Mechanism of Bi-Functional Nickel-Iron Phosphides Catalysts for Overall Water Splitting,” Advanced Functional Materials 33, no. 33 (2023): 2302621.

[27] Q. He, D. Tian, H. Jiang, et al., “Achieving Efficient Alkaline Hydrogen Evolution Reaction Over a Ni₅P₄ Catalyst Incorporating Single-Atomic Ru Sites,” Advanced Materials 32, no. 11 (2020): 1906972.

[28] D. Chen, R. Lu, Z. Pu, et al., “Ru-Doped 3D Flower-Like Bimetallic Phosphide With a Climbing Effect on Overall Water Splitting,” Applied Catalysis, B: Environmental 279 (2020): 119396.

[29] S. -H. Cai, X. -N. Chen, M. -J. Huang, J. -Y. Han, Y. -W. Zhou, and J. -S. Li, “Interfacial Engineering of Nickel/Iron/Ruthenium Phosphides for Efficient Overall Water Splitting Powered by Solar Energy,” Journal of Materials Chemistry A 10 (2022): 772-778.

[30] X. Li, Z. Niu, M. Niu, J. Wang, D. Cao, and X. Zeng, “Single Atom Ru Doped Ni₂P/Fe₃P Heterostructure for Boosting Hydrogen Evolution for Water Splitting,” Small 20, no. 27 (2024): 2311335.

[31] Y. Tan, H. Wang, P. Liu, et al., “Versatile Nanoporous Bimetallic Phosphides Towards Electrochemical Water Splitting,” Energy & Environmental Science 9 (2016): 2257-2261.

[32] X. Jin, T. -H. Gu, N. H. Kwon, and S. -J. Hwang, “Synergetic Advantages of Atomically Coupled 2D Inorganic and Graphene Nanosheets as Versatile Building Blocks for Diverse Functional Nanohybrids,” Advanced Materials 33, no. 47 (2021): 2005922.

[33] C. Taviot-Guého, V. Prévot, C. Forano, G. Renaudin, C. Mousty, and F. Lerous, “Tailoring Hybrid Layered Double Hydroxides for the Development of Innovative Applications,” Advanced Functional Materials 28, no. 27 (2018): 1703868.

[34] X. Jin, T. Lee, W. Tamakloe, et al., “In Situ Defect Engineering Route to Optimize the Cationic Redox Activity of Layered Double Hydroxide Nanosheet via Strong Electronic Coupling With Holey Substrate,” Advanced Science 9, no. 1 (2022): 2103368.

[35] N. Kim, T. -H. Gu, D. Shin, et al., “Lattice Engineering to Simultaneously Control the Defect/Stacking Structures of Layered Double Hydroxide Nanosheets to Optimize Their Energy Functionalities,” ACS Nano 15, no. 5 (2021): 8306-8318.

[36] J. Lee, J. Lee, X. Jin, H. Kim, and S. -J. Hwang, “Atomically-Thin Holey 2D Nanosheets of Defect-Engineered Mon−Mo₅N₆ Composites as Effective Hybridization Matrices,” Small 20, no. 9 (2024): 2306781.

[37] P. Xiao, W. Chen, and X. Wang, “A Review of Phosphide-Based Materials for Electrocatalytic Hydrogen Evolution,” Advanced Energy Materials 5, no. 24 (2015): 1500985.

[38] A. Ray, S. Sultana, L. Paramanik, and K. M. Parida, “Recent Advances in Phase, Size, and Morphology-Oriented Nanostructured Nickel Phosphide for Overall Water Splitting,” Journal of Materials Chemistry A 8 (2020): 19196-19245.

[39] H. Zhang, W. Liu, Z. Li, et al, “Constructing CoP/Ni₂P Heterostructure Confined Ru Sub-Nanoclusters for Enhanced Water Splitting in Wide pH Conditions,” Advancement of Science 11, no. 35 (2024): 2401398.

[40] X. Guo, W. Zang, X. Li, Z. Wang, L. Zheng, and Z. Kou, “Achieving Efficient Alkaline Hydrogen Evolution Reaction on Long-Range Ni Sites in Ru Clusters-Immobilized Ni₃N Array Catalyst,” Chemical Engineering Journal 451 (2023): 138698.

[41] X. Jin, H. Jang, N. Jarulertwathana, M. G. Kim, and S. -J. Hwang, “Atomically Thin Holey Two-Dimensional Ru₂P Nanosheets for Enhanced Hydrogen Evolution Electrocatalysis,” ACS Nano 16, no. 10 (2022): 16452-16461.

[42] R. Yang, Y. Zhou, Y. Xing, et al., “Synergistic Coupling of CoFe-LDH Arrays With NiFe-LDH Nanosheet for Highly Efficient Overall Water Splitting in Alkaline Media,” Applied Catalysis, B: Environmental 253 (2019): 131-139.

[43] C. Lu, T. -H. Kim, J. Bendix, et al., “Stability of Magnetic LDH Composites Used for Phosphate Recovery,” Journal of Colloid and Interface Science 580 (2020): 660-668.

[44] S. S. Jeon, P. W. Kang, M. Klingenhof, H. Lee, F. Dionigi, and P. Strasser, “Active Surface Area and Intrinsic Catalytic Oxygen Evolution Reactivity of NiFe LDH at Reactive Electrode Potentials Using Capacitances,” ACS Catalysis 13, no. 2 (2023): 1186-1196.

[45] S. -J. Hwang, C. -W. Kwon, J. Portier, et al., “Local Crystal Structure Around Manganese in New Potassium-Based Nanocrystalline Manganese Oxyiodide,” Journal of Physical Chemistry B 106, no. 16 (2002): 4053-4060.

[46] Z. Zhou, Y. Kong, H. Tan, et al., “Cation-Vacancy-Enriched Nickel Phosphide for Efficient Electrosynthesis of Hydrogen Peroxides,” Advanced Materials 34, no. 16 (2022): 2106541.

[47] S. Fujita, S. Yamaguchi, S. Yamazoe, J. Yamasaki, T. Mizugaki, and T. Mitsudome, “Nickel Phosphide Nanoalloy Catalyst for the Selective Deoxygenation of Sulfoxides to Sulfides Under Ambient H₂ Pressure,” Organic & Biomolecular Chemistry 18 (2020): 8827-8833.

[48] Y. Chen, J. Meng, M. Xu, et al, “Adaptive Active Site Turning for Superior OER and UOR on Ir-Ni₃N Catalyst,” Advanced Functional Materials 35, no. 3 (2024): 2413474.

[49] Y. Fang, D. Sun, S. Niu, et al., “Orbital-Regulated Interfacial Electronic Coupling Endows Ni₃N With Superior Catalytic Surface for Hydrogen Evolution Reaction,” Science China Chemistry 63 (2020): 1563-1569.

[50] S. Yao, V. Forstner, P. W. Menezes, et al., “From an Fe₂P₃ Complex to FeP Nanoparticles as Efficient Electrocatalysts for Water-Splitting,” Chemical Science 9 (2018): 8590-8597.

[51] P. Sathishkumar, S. Anandan, P. Maruthamuthu, T. Swaminathan, M. Zhou, and M. Ashokkumar, “Synthesis of Fe³⁺ Doped TiO₂ Photocatalysts for the Visible Assisted Degradation of an Azo Dye,” Colloids and Surfaces, A: Physicochemical and Engineering Aspects 375, no. 1-3 (2011): 231-236.

[52] J. H. Yu, N. Voronina, N. Yaqoob, et al., “Migration of Mg in Na−O−Mg Configuration for Oxygen Redox of Sodium Cathode,” ACS Energy Letters 9, no. 1 (2024): 145-152.

[53] Y. Sun, J. Lee, N. H. Kwon, et al., “Enhancing Hydrogen Evolution Reaction Activity of Palladium Catalyst by Immobilization on MXene Nanosheets,” ACS Nano 18, no. 8 (2024): 6243-6255.

RIGHTS & PERMISSIONS

2025 The Author(s). Carbon Energy published by Wenzhou University and John Wiley & Sons Australia, Ltd.