Duff5OOO OP t1_j00a9ed wrote on December 13, 2022 at 3:32 AM

>As part of their experiments the team measured the amount of hydrogen produced through electrolysis with and without sound waves from the electrical output.

>“The electrical output of the electrolysis with sound waves was about 14 times greater than electrolysis without them, for a given input voltage. This was equivalent to the amount of hydrogen produced,” Ehrnst said.

The I guess more important figure:

>“With our method, we can potentially improve the conversion efficiency leading to a net-positive energy saving of 27%.”

Combined with the cheaper metals used it looks like an interesting development.

RebelWithoutAClue t1_j00ewtv wrote on December 13, 2022 at 4:10 AM

I wish they said something about current draw. Im not clear that they were getting 14x more gas production per unit power or just a higher speed of production at constant voltage.

I used to have an electrolysis rig when I was a kid. I used carbon electrodes pulled out of old D cell carbon batteries.

I would find that gas production would slow fairly quickly unless I periodically tapped the electrodes to shake gas off of the electrodes. The accumulated bubbles would reduce contact with the water and production rate but my current draw would also decline.

I don't recall getting better gas production rate per unit power by knocking off the bubbles though.

I also remember having problem with calcium buildup fouling my electrodes. I got better results with distilled water, but I imagine that the energy required to distil water is pretty nuts. Maybe I could have used rainwater.

Duff5OOO OP t1_j00g4on wrote on December 13, 2022 at 4:21 AM

Did you check out the paper linked at the bottom?

https://onlinelibrary.wiley.com/doi/10.1002/aenm.202203164

RebelWithoutAClue t1_j00wfra wrote on December 13, 2022 at 7:14 AM

Thanks for that smack. I forget to look at papers directly when I'm on a phone because a phone is an abysmal platform for looking at complicated things.

I sure hurt my head trying to parse all of that. To be honest my experience with electrolysis principles is not far from being a layperson.

I had some fun generating hydrogen and oxygen gas mixtures for my potato cannon experiments way back in junior HS (somewhere back in the late '80's). I made some really neat observations on my ammeter that lined up with qualitative observations like the fizz rate would drop fairly quickly at the same time as current flow rate.

I could start my electrolysis cell with a good surge of current at the start, but in not very long current would drop quickly. I figured that it was bubble attachment and that seemed to be the problem because a sharp tap to the bottom of my setup would result in a bunch of detached bubbles and a surge of current only to decline again.

I hot glued a motor with a lead fishing weight pinched onto the output shaft to the bottom of the tank (a polypropylene tofu tub) so when I ran the motor it'd vibrate the floor and help shed bubbles. It made a big difference to my gas production.

I've tried to parse my way through that study a couple times and I can't find any reference to actual gas production rates. There is a lot of discussion of improvements to current density vs. voltage which should be a good thing. I am assuming that they are working on the assumption that their current density is going to be their bulk current divided by their exposed electrode area under the assumption that they have no bubbles attached to their electrodes.

This could be a good assumption if the macro observation is that there is never any bubbles stuck to the electrodes. Maybe this is a thing that can be easy to confirm visually.

I have to concede that it would be difficult to come up with a meaningful current per unit area if bubble attachment is an issue because it would be very difficult to measure the area of bubble attachment to calculate actual current per unit area.

It would be far easier to assume no bubble attachment and calculate current per area on that assumption. If the assumption is wrong then one would require higher voltages to drive the same current and that does not appear to be the case, based on their observations that sonicating the bath is reducing the voltage to drive similar current.

My inner dickhead concedes that they are actually achieving a better current flow per unit voltage with their ultrasonic trick, if their results are to be accepted.

Still I would have liked to have seen a gas per power expenditure. Run the electrolysis cell long enough and you'd have a handy checksum accounting of your efficiency improvement to "close the loop" on your voltage and current measurements. Also it would be a bulk observation that the layperson could understand without needing to understand the principles, which a monkey like me would appreciate.

I kind of wish that they crunched their numbers in a way to compare against Gibbs Free energy. I remember a list of chemical reactions that were related to change in enthalpy in HS. I imagine that we are trying to approach an ideal Gibbs Free energy limit so it would be useful to compare improvements in electrolysis in terms of efficiency relative to GFE limits.

I suppose the one thing that is remaining is that I do not know how much power was inputted to their ultrasonic transducer. What was the power required to run their transducer?

Piezo elements aren't very efficient (something like 10% efficient) and liquid mediums tend to eat ultrasonic energy and convert it to heat like mad.

It may be a neat trick to boost output with a sonifier, but it may be that the the effects they're playing with require too much transducer power which negates their 27% efficiency boost.

I remember dumping a bunch of salt into my water bath to increase my rate of gas production. It worked like a charm! I probably quadrupled my gas production rate! I lit a cup of gas mix to celebrate and was treated to a nice loud pop and a kind of funny different flame colour which was immediately intriguing.

Then it hit me as it hit my eyes and lungs: I had ignited a mix of hydrogen and chlorine which was making HCL in my mucous membranes and I just gassed myself...

Duff5OOO OP t1_j010vna wrote on December 13, 2022 at 8:12 AM

> I forget to look at papers directly when I'm on a phone because a phone is an abysmal platform for looking at complicated things.

I completely missed it when i originally looked on my phone. Tried to look up "Advanced Energy Materials" and had no luck. Only found it was linked later when i was at my PC. Figured you may have had the same trouble i had :)

>I sure hurt my head trying to parse all of that.

Ditto. Much of it is well past my understanding without spending the night looking up a heap of different side topics to get an idea on what's going on.

"Our investigations reveal a further dominant mechanism is at play: in the same way that the extraordinary surface acceleration ( m s−2)) (Figure 1b,c), local evanescent electric field ( V m−1)) and pressure (–1 MPa)) associated with the SRBW-forcing has been shown previously to drive free radical and proton formation,[31, 32] we show from an examination of the interfacial water structure via Raman spectroscopy, evidence for the disruption of the tetrahedral hydrogen bond water network of the neutral electrolyte."

???

We need an AMA with someone involved. :)

The cost savings with electrolyte and electrode i get. Sounds promising by itself. Would like some more info on gas volume produced per unit of energy input as a total system.

>I had ignited a mix of hydrogen and chlorine which was making HCL in my mucous membranes and I just gassed myself...

Nice one! A least you noticed early enough :)

RebelWithoutAClue t1_j011ykd wrote on December 13, 2022 at 8:27 AM

I looked up Raman spectroscopy on wikipedia. I think they're shooting a laser at the working area of the electrodes to observe the wavelengths of scattered light. It appears to me that they are applying a kind of molecular emissions spectroscopy where they excite their sample region with a chosen wavelength of laser to excite the molecules in the region. The molecules enter a higher energy state, due to laser excitation, and when they "come back down" to a lower energy level the emit light of different wavelengths which may be analyzed. Also the emissions spectra of disassociated protons and OH radicals will have their own character that can be observed.

I suppose that they observe a different emissions spectra when they're making noise and electrolyzing than when they aren't making noise. I sure hope that they're not affecting their experiment with their use of their laser because it surely is a wavelength that can affect water molecules.

Anyways it doesn't appear to involve alkaline treated noodles as far as I can tell.

For the record: I did not notice the strange emissions spectra of my gas combustion trial soon enough. I saw a funny colour that wasn't the usual purple hue and said "huh"... Then my eyeballs, sinuses, and lungs were getting fried when I took my next breath as my brain assimilated it's findings a few seconds too late.

TA_faq43 t1_j00cqr3 wrote on December 13, 2022 at 3:52 AM

Is it bsically agitating the electrolysis so more atoms are coming into contact vs passive state? Would increasing the temperature also have similar effect?