For first time, researchers witnessed formation of nanosized water bubbles in real time and at the molecular-scale. Here, the scientists observed hydrogen and oxygen atoms merge to form tiny, nano-sized bubbles of water. This demonstrated how palladium, a rare metallic element, can rapidly generate water from hydrogen and oxygen. The element catalyzes the gaseous reaction to generate water.
Since the early 1900s, researchers have known that palladium can act as a catalyst to rapidly generate water. But how, exactly, this reaction occurs has remained a mystery. Viewing the process with atomic precision was simply impossible, at least until nine months ago.
The researchers from Northwestern University witnessed this process at the nanoscale for the first time with an electron microscope. By viewing the process with extreme precision, they discovered how to optimize it to generate water at a faster rate.
The new process could be used to generate water on-demand in extreme environments, including on other planets. This is useful since the reaction does not require extreme conditions; hence, the researchers say it could be harnessed as a practical solution for rapidly generating water in arid environments.
For the experiment, the scientists developed an ultra-thin glassy membrane that holds gas molecules within honeycomb-shaped nanoreactors, so they can be viewed within high-vacuum transmission electron microscopes.
Here the researchers can examine samples in atmospheric pressure gas at a resolution of just 0.102 nanometers, compared to a 0.236-nanometer resolutionusing other state-of-the-art tools. The technique also enabled, for the first time, concurrent spectral and reciprocal information analysis.
The researchers think their observation might be the smallest bubble ever formed that has been viewed directly. A process called electron energy loss spectroscopy, to analyze the bubbles.
“By directly visualizing nanoscale water generation, we were able to identify the optimal conditions for rapid water generation under ambient conditions,” states Northwestern’s Vinayak Dravid, senior author of the study. “These findings have significant implications for practical applications, such as enabling rapid water generation in deep space environments using gases and metal catalysts, without requiring extreme reaction conditions.”
Dravid adds: “Think of Matt Damon’s character, Mark Watney, in the movie ‘The Martian.’ He burned rocket fuel to extract hydrogen and then added oxygen from his oxygenator. Our process is analogous, except we bypass the need for fire and other extreme conditions. We simply mixed palladium and gases together.”
The research has been published in the Proceedings of the National Academy of Sciences. The study is titled “Unraveling the adsorption-limited hydrogen oxidation reaction at palladium surface via in situ electron microscopy”.
