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Science

Chemists Discover Water Microdroplets Spontaneously Produce Hydrogen Peroxide (phys.org) 36

An anonymous reader quotes a report from Phys.Org: Stanford researchers report Aug. 26 in Proceedings of the National Academy of Sciences that microscopic droplets of water spontaneously produce hydrogen peroxide. The discovery could pave the way for greener ways to produce the molecule, a common bleaching agent and disinfectant, said Richard Zare, the Marguerite Blake Wilbur Professor in Natural Science and a professor of chemistry in the Stanford School of Humanities and Sciences. The discovery was made serendipitously while Zare and his lab were studying a new, more efficient way to create gold nanostructures in tiny water droplets known as microdroplets. To make those structures, the team added an additional molecule called a reducing agent. As a control test, Zare suggested seeing if they could create gold nanostructures without the reducing agent. Theoretically that should have been impossible, but it worked anyway -- hinting at an as yet undiscovered feature of microdroplet chemistry.

The team eventually traced those results to the presence of a molecule called hydroxyl -- a single hydrogen atom paired with an oxygen atom -- that can also act as a reducing agent. That equally unexpected result led Katherine Walker, at the time a graduate student in Zare's lab, to wonder whether hydrogen peroxide -- a molecule with two hydrogen and two oxygen atoms -- was also present. To find out, Zare, Walker, staff scientist Jae Kyoo Lee and colleagues conducted a series of tests, the simplest of which involved spraying ostensibly pure water microdroplets onto a surface treated so that it would turn blue in the presence of hydrogen peroxide -- and turn blue it did. Additional tests confirmed that water microdroplets spontaneously form hydrogen peroxide, that smaller microdroplets produced higher concentrations of the molecule, and that hydrogen peroxide was not lost when the microdroplets recombined into bulk water.
The researchers suggest that a strong electric field near the surface of water microdroplets in air triggers hydroxyl molecules to bind into hydrogen peroxide.
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Chemists Discover Water Microdroplets Spontaneously Produce Hydrogen Peroxide

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  • The G7 countries (and others) share freely their discoveries in the fields of science, while others (China, Russia) do not share everything. That's great to live in a free country... but isn't the free science sharing a bit risky?
    • by AHuxley ( 892839 )
      China will invite some other nations experts in to build a new factory.
      No tax, great investment. Lots of skilled low cost workers. Export to the world.
      Make lot of profit quickly in China.
      The investment is approved and the new tech is in place.
      A short time later the same factory is found all over China.
      The Communist courts do nothing.
      Winning.

      The Wests security services where too politically controlled to not allow that loss of advanced tech to China.

      Your question about Russia.
      They watch wha
  • Did they check if there is some pure hydrogen in there also?    Would be cool if we could just mist water and collect hydrogen gas, h202, etc.
    • Would be cool if we could just mist water and collect hydrogen gas, h202, etc.

      Excellent! Drive up to the gas station and tell the attendant, "Fill'er up with hydrogen producing water microdroplets" for your hydrogen powered car.

      And as plus . . . Hydrogen Burning Funny Cars . . . as opposed to Nitro Burning Funny Cars . . . give out more water as exhaust. Which means even more hydrogen producing water microdroplets!

      How more renewable can you get than that . . . ?

  • by burningcpu ( 1234256 ) on Wednesday August 28, 2019 @02:25AM (#59132032)
    The abstract gives more detail and is less annoying. Unfortunately the article is paywalled.

    We show H2O2 is spontaneously produced from pure water by atomizing bulk water into microdroplets (1 m to 20 m in diameter). Production of H2O2, as assayed by H2O2-sensitve fluorescence dye peroxyfluor-1, increased with decreasing microdroplet size. Cleavage of 4-carboxyphenylboronic acid and conversion of phenylboronic acid to phenols in microdroplets further confirmed the generation of H2O2. The generated H2O2 concentration was 30 M (1 part per million) as determined by titration with potassium titanium oxalate. Changing the spray gas to O2 or bubbling O2 decreased the yield of H2O2 in microdroplets, indicating that pure water microdroplets directly generate H2O2 without help from O2 either in air surrounding the droplet or dissolved in water. We consider various possible mechanisms for H2O2 formation and report a number of different experiments exploring this issue. We suggest that hydroxyl radical (OH) recombination is the most likely source, in which OH is generated by loss of an electron from OH at or near the surface of the water microdroplet. This catalyst-free and voltage-free H2O2 production method provides innovative opportunities for green production of hydrogen peroxide.

    https://www.pnas.org/content/early/2019/08/20/1911883116#sec-6

    I have a few thoughts regarding the study. First, I disagree strongly that rearrangement of a boron-containing molecule, under these conditions, is evidence for the presence of peroxide. Boron is a highly mobile element and nebulization is known to 'splatter' apart such organics. What happens, is a small charge forms on the surface of a water droplet, and as the droplet sheds molecules through evaporation, the charge concentrates among the remaining. This is called electrospray ionization. Rearrangement and subsequent release of boron is the expected result of nebulization of such a chemical.

    The concentration determined via titration was 30x10-6M. I am suspicious of the validity of this data for several reasons. The titration is a redox-reaction and is not specific to peroxide. I have the same objection to the starch-indicator-strips they describe. Further, 30uM would be considered a trace concentration, WRT a nonspecific redox titration.

    Basically, I'd need to see lots of data to support their analytical methods, before I'd buy into any of this. I don't think they have a handle on the principles.

    • I'm pretty sure it is true. It is published by Scientists and I read about it on the Internet.

    • by eth1 ( 94901 )

      We show H2O2 is spontaneously produced from pure water by atomizing bulk water into microdroplets (1 m to 20 m in diameter).

      I'm not sure I'd class water droplets 1-20 meters in diameter as "micro"...

  • Don't make me

      {laugh?}

    It only spurts when I....

      {laugh?}

  • Comment removed based on user account deletion
  • Apparently the water was contaminated with hydroxylic acid.

  • by Chromal ( 56550 ) on Wednesday August 28, 2019 @01:15PM (#59133652)
    Does this mean the mist coming off of waterfalls contains hydrogen peroxide? Does this have a cleansing effect on the water or air in the vicinity?

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