ナノバブル化学により、穏和な条件下で触媒を必要としないアンモニア合成を実現(Nanobubble Chemistry Enables Catalyst-Free Ammonia Synthesis Under Mild Conditions)

2026-08-24 中国科学院(CAS)

中国科学院(CAS)の研究チームは、ナノバブルの崩壊時に生じる高エネルギーの反応性を利用し、触媒を使わず、室温・低圧でアンモニアを合成する新手法を開発した。N₂/H₂ナノバブルの崩壊で発生するH・ラジカルが窒素固定を促進し、アンモニアへの選択率約60%を達成。EPR測定とDFT計算から、生成するH・ラジカルの化学ポテンシャルは約2.3 eVに達し、N≡N結合活性化に必要な1.59 eVを上回ることが示された。これは400℃超・200気圧程度を要する従来のハーバー・ボッシュ法とは異なり、ナノバブルを局所的な「マイクロリアクター」として利用する新たな反応パラダイムである。省エネルギー・低炭素なアンモニア製造への応用に加え、高エネルギー障壁反応の新しい活性化手段としても期待される。

ナノバブル化学により、穏和な条件下で触媒を必要としないアンモニア合成を実現(Nanobubble Chemistry Enables Catalyst-Free Ammonia Synthesis Under Mild Conditions)
Scheme for nanobubble chemistry including both generation and implosion of the nanobubble in solution (Image from NCNST)

<関連情報>

ナノバブルラジカル駆動型N₂水素化による持続可能なアンモニア生産:穏やかな条件下でのハーバー・ボッシュ反応の代替法 Nanobubble Radical-Driven N2 Hydrogenation for Sustainable Ammonia Production: A Haber-Bosch Alternative under Mild Conditions

Shangkun Jin;Ruiyi Zhang;Lan Chen ;Guanglu Ge
Journal of the American Chemical Society  Published:August 20, 2026
DOI:https://doi.org/10.1021/jacs.6c06081

Abstract

Ammonia is a cornerstone for global agriculture and promising renewable energy storage, yet its production through the conventional Haber-Bosch process accounts for nearly 2% of worldwide energy consumption, underscoring the urgent need for sustainable alternatives. Recent advances in interfacial chemistry, such as droplet-assisted reactions, have demonstrated unique reactivity in confined environments under mild conditions. However, many of these approaches rely on hydroxyl radicals and exhibit limited selectivity toward oxygen-free hydrogen-rich products like ammonia. Here, we report a catalyst-free nitrogen fixation strategy that achieves high ammonia selectivity (∼60%) using nanobubble-driven radical chemistry at ambient temperature and pressure. By harnessing the cavitation-decoupled N2/H2 nanobubbles collapsing in water, our system enables spontaneous nitrogen fixation with an optimized ammonia yield of ∼0.24 mg·L−1 achieved through 30 min nanobubble generation and subsequent 24 h standing, driven primarily by hydrogen radicals in a mechanism reminiscent of confined implosion. This collapse generates localized transient extremes of temperature and pressure, which promotes the formation of reactive hydrogen radicals. The high chemical potential of these radicals (∼2.3 eV) directly supplies the energy required for N≡N bond activation, eliminating the need for catalysts and external energy input. Beyond offering a scalable and energy-efficient route to green ammonia synthesis, this study provides mechanistic insight into prebiotic nitrogen-fixation pathways. The approach aligns with the global transition toward decentralized, low-carbon chemical production and contributes to a sustainable future for both energy and agriculture.

0500化学一般
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