水微液滴气–液界面单电子介导的氧化还原过程

Single-electron-mediated redox processes at the air-water interface of water microdroplets

水通常被认为是一种稳定的溶剂,然而当把水分散成微米级大小的微液滴后,其将展现出许多独特的性质.这些性质中最引人注目的就是微液滴表面自发形成的高达10^(9)V m^(-1)的电场,该电场能够将水中的氢氧根离子或其他闭壳层分子中的电子撕扯出来,生成自由基和电子,从而进一步触发氧化还原反应.本文综述了40余种单电子介导水微液滴表面自发的氧化还原反应并讨论了相应的反应动力学,论证了此类反应的本质是以电子作为“载流子”的过程.最后,结合合成化学和大气化学的背景,我们对微液滴的氧化还原能力的潜在且广泛的影响进行了讨论和展望.

Water is typically regarded as a stable solvent;however,when dispersed into microdroplets,it exhibits numerous distinctive properties.The most notable one among these properties is the spontaneously formed electric field on the surface of microdroplets,reaching up to 10^(9)V m^(-1).This electric field has the capacity to dislodge electrons from hydroxide ions or from closed-shell molecules in water,yielding radicals and electrons.Consequently,this process further initiates redox reactions.This article provides a comprehensive overview of more than 40 types of singleelectron-mediated spontaneous redox reactions occurring on the surfaces of water microdroplets.The corresponding reaction kinetics is discussed,underscoring the intrinsic electron-driven nature of these reactions.Finally,by integrating perspectives from synthetic chemistry and atmospheric chemistry,we explore and anticipate the broad and potential impacts of the redox capabilities of microdroplets.