https://doi.org/10.1021/jacs.6c06081
http://english.cas.cn/newsroom/research-news/202608/t20260824_1188763.shtml
A research team led by Profs. CHEN Lan and GE Guanglu from the CAS National Center for Nanoscience and Technology (NCNST) has developed a catalyst‑free nanobubble chemistry strategy for ammonia synthesis at room temperature and low pressure.
By harnessing free radicals generated from the collapse of N2/H2 bulk nanobubbles, the team achieved nitrogen fixation with about 60% selectivity toward ammonia. EPR capture and DFT calculations showed that the chemical potential of H· radicals generated in situ during nanobubble collapse reaches about 2.3 eV, sufficient to directly supply the energy required for N≡N bond activation (energy barrier: 1.59 eV), thereby bypassing the high energy input and catalytic conditions required by traditional pyrolysis.
Nanobubble chemistry deals with reactions driven by gas bubbles at the nanoscale, typically less than one μm in diameter. According to the Young‑Laplace equation, a 100‑nm bubble can contain internal pressure of several dozen atmospheres. What is more, nanobubbles possess a unique boundary layer and release abundant reactive free radicals when they collapse, making them natural “microreactors” that can drive reactions normally requiring extreme conditions. This approach offers value not only in providing transient localized high temperature and pressure, but also in supplying radical chemical potential with precision—opening up a completely new activation pathway for high‑energy‑barrier reactions.
Scheme for nanobubble chemistry including both generation and implosion of the nanobubble in solution (Image from NCNST)