2026-05-07 スタンフォード大学
＜関連情報＞
- https://news.stanford.edu/stories/2026/05/metals-nanocrystal-clean-hydrogen-energy-research
- https://www.science.org/doi/10.1126/science.aea8044
競合反応性が多金属ナノ結晶におけるサイズと組成の集中を促進する Competitive reactivity drives size- and composition-focusing in multimetallic nanocrystals
Jeesoo Yoon, Jinwon Oh, Dongjun Kim, Pin-Hung Chung, […] , and Matteo Cargnello
Science Published:7 May 2026
DOI:https://doi.org/10.1126/science.aea8044
Editor’s summary
Multimetallic nanocrystals offer valuable properties but are challenging to synthesize. Yoon et al. systematically explored how the interplay of ruthenium seeds with iron, cobalt, nickel, and copper precursors can be exploited to produce uniform pentametallic nanocrystals. They showed that progressive addition of multiple metals suppresses unwanted nucleation and directs growth toward a uniform product. The resulting nanocrystals exhibited high thermal stability and enhanced catalytic activity for ammonia decomposition, highlighting a general strategy for designing complex functional nanomaterials. —Jack Huang
Structured Abstract
INTRODUCTION
Multimetallic nanocrystals exhibit physical and chemical properties unattainable in monometallic systems, arising from the synergistic interplay of their constituent elements. Synthesizing these materials with precise control over their size and composition represents an important goal. Differences in reduction potentials, interfacial energies, and nucleation and growth kinetics among metal precursors create both thermodynamic and kinetic challenges that often lead to asynchronous reduction and incorporation processes. Rather than forming a single, uniform product, these disparities frequently generate multiple particle populations with distinct sizes and compositions. Therefore, rational design principles that govern competitive reduction and growth processes are critical to directing multimetallic synthesis toward uniform products.
RATIONALE
We hypothesized that the inherent chemical complexity of reduction for multiple metal precursors could be exploited rather than avoided. Specifically, we investigated whether introducing a high number of different competing metals simultaneously during a seed-mediated synthesis might suppress the formation of unwanted heterogeneous products. Under such competitive conditions, mutual affinities and altered energy barriers control the reaction pathways, guiding synthesis toward a single, compositionally uniform product.
RESULTS
We discovered a counterintuitive, composition-focusing effect in which increasing the number of reacting metals dramatically improved product uniformity. Whereas introducing one or two base metals to ruthenium seeds yielded inhomogeneous products, simultaneously adding four metal precursors suppressed side reactions, resulting in a single pentametallic nanocrystal product. Time-lapse analysis during the heating process demonstrated that the metals deposited sequentially. The initial elements that deposited acted as mediators that lowered the energy barrier for the addition of subsequent metals, building a multidomain architecture. This focusing phenomenon also proved highly versatile, successfully yielding uniform products regardless of seed size, precursor ratios, or the constituent metals. When used as ammonia decomposition reaction catalysts, the pentametallic nanocrystal-based catalysts achieved a catalytic rate more than four times higher than that of ruthenium catalysts and maintained their structural integrity and performance even after high-temperature treatments up to 900°C.
CONCLUSION
Our study demonstrates that competitive reactivity, typically viewed as a hurdle in chemical synthesis, can actively drive the formation of highly uniform multimetallic nanocrystals. By increasing the number of competing elements, side reactions could be suppressed to focus the growth into a single structure. The design rules established in this study provide a generalizable strategy for synthesizing complex multimetallic nanocrystals, offering a versatile platform for advancing catalysis and sustainable energy technologies.
Composition-focusing in multimetallic nanocrystal synthesis.
Increasing the number of constituent metals triggers a composition-focusing effect that leads to uniform nanocrystals. This phenomenon is driven by sequential co-reduction, in which initial metal deposition mediates synergistic incorporation of subsequent elements (scale bar, 10 nm). The resulting pentametallic nanocrystals maintain structural integrity and catalytic performance as supported catalysts during the ammonia decomposition reaction.
Abstract
Multimetallic nanocrystals (NCs) offer distinctive properties driven by synergistic interactions among their constituent metals. Although colloidal chemistry enables control over size and composition, competing reactivities among metal precursors often complicate the synthesis of complex NCs. In this study, we systematically elucidate how the competitive reactivity of different metals in solution can be exploited to synthesize uniform pentametallic NCs despite numerous competing pathways. Mechanistic studies reveal heterodimers as key intermediates that mediate further metal incorporation through selective nucleation. Notably, the addition of more metals suppresses homogeneous nucleation, resulting in size- and composition-focusing to produce complex NCs with distinct multimetallic domains. When supported, these NCs show excellent thermal stability and catalytic activity for ammonia decomposition, offering a promising strategy for designing complex nanomaterials for energy-related applications.
