Hydrolysis: Electrodes best suited to split water

A. I use graphite rods and titanium welding rods as electrodes when exfoliating carbon nanoparticles via hydrolysis but I also fix CO2 in salt water by hydrolysis and use any austenitic stainless steel material to do so, e.g., stainless steel mesh, rods or scrubbing pads. You can also use copper and aluminum foil electrodes. Consider corrosion byproducts and their influence on performance and contamination of electrolyte in making your decision.

I don't want stray metal ions impregnating my nanoparticles or copper halides fouling my electrolyte solution. If however my only concern were to produce hydrogen gas, then low cost conductors would be acceptable to me as long as disposal of electrolyte solution is not made more complicated. If you're considering large quantities of gas production then I suggest you contact the Douglas County Public Utility District in Washington State. The use hydrolysis and hydrogen fuel cells as a means of storing excess power production from their hydro dams.

A. Hi Paul. Platinum anodes or platinum-clad titanium anodes are probably really the "right" material, but they would probably be expensive. If you are looking for a cheap experiment, maybe you could try using the carbon/graphite rods from a conventional carbon-zinc dry cell battery?

A. Carbon is probably a bad choice as a lot of it has zinc and traces of nasty metals. I would go to a cheap kitchen shop and buy a stainless mesh screen or even disassemble a strainer. While not as good as 316, any 18-8 or 304 stainless is cheap and very accessible. Even 316 will deteriorate if there are chlorides in the water, just will not do it quite as fast. Keep the voltage down, probably under 4 volts, lower if possible. Remember, greater surface area will give greater amperage without the destructive effects of high voltage, which is somewhat limited in the max amount of amps that you can drive thru it. Stainless is a lousy conductor of electricity. use copper leads and seal them with wax or an appropriate paint.

A. They are not cheap, but I would expect platinum clad titanium anodes to be quite durable.

A. From my days at school, in the dim and distant past, I have a recollection of electrolysing water using simple graphite electrodes.

A. The best electrodes are made from platinum, but this is expensive, especially if you need large areas, so a common cheaper answer is to use platinised titanium, which is titanium coated in a thin layer of platinum. For real cheapness, use graphite, but this will ultimately disintegrate. Most other metals will either oxidise or dissolve and become progressively more useless.

A. The answer depends on what you want to achieve.
For simple experimental purposes, stainless steel is cheap and practical.
If you are considering a serious commercial application you will find that most commercial electrolyzers operate in alkaline conditions (KOH) and use either steel electrodes or nickel plated steel. To be commercially viable requires a low operating voltage i.e., low discharge overpotential. There is a great deal of information in Modern Aspects of electrochemistry No 15 Ed ralph White et al Published by Plenum Press.
Alternatively, you could buy one ready made from Brown Boveri, DeNora, Lurgi, Norsk Hydro, The Electrolyzer Corp., Telydyne, etc.

A. There are many sites on the topic of powering cars from water/hydrogen, Randy. Maybe try putting 'hydrogen from water' into your search engine? But there are as many quack sites as there are useful sites. An easy way you can tell the difference is that the quack sites will claim or imply that a conspiracy by the oil companies, car companies, and government is "preventing you from using this free energy source", whereas the valid sites will explain thermodynamic principles and that to generate hydrogen from water requires you to put more energy in than you will get out from burning the hydrogen.

You might consider novel approaches like using solar heat plus a catalyst to convert solar energy directly to the liberation of hydrogen from water. You still can't get more energy out of burning the hydrogen than you collected from the sun, but at least you don't have to eat the transmission losses in electrical lines. Good luck!

A. Hi Alan. You might put your electrodes in salt water with the current off for a couple of weeks as a test, because I don't think galvanic corrosion is the issue, but rather de-plating caused by the impressed voltage.

If the electrodes don't have to carry heavy current you could try platinum-clad titanium because they won't de-plate under most conditions. If titanium can't carry the current, you would probably have to platinum plate copper electrodes -- but electrodeposition of platinum isn't easy.

Regards,

A. You might try platinum clad niobium for this application.

A. Hi Alan. It doesn't take much voltage to de-plate a metal, so I think the experiment will prove informative.

"Cladding" requires a thick enough covering that it be completely non-porous and pinhole-free even after allowing for some erosion and corrosion. Some types of cladding are done by autoclaving a skin of one material onto another material, and then rolling them down to thinner gauges.

Years ago I was tangentially involved in the installation of an electroplating line at a manufacturer of Dimensionally Stable Anodes, so I know that clad anodes can be manufactured by electroplating. I am not familiar with the chemistry that they employed (but wouldn't be allowed reveal it if I was) :-(

Regards,

A. Try carbon electrodes. Just an Idea.

A. Hi Kishor,

Any kind of current induced in water will produce the brown water. It depends on the quality of water and its mineral content.

Ion foot detox uses this fundamental as a neat trick to sell this foot detox thingy.

One gets a big thrill watching the water turn brown and assuming that one has been detoxified (Including yours truly).

Sorry I can't suggest any remedy; try selling foot detox as an alternative business product?

A. Hi Kishor. I think Khozem was trying to good-naturedly inform you that the water turning brown is an inherent part of your premise of electrolizing salty water with dissolved minerals in it, especially using iron-based electrodes. When you apply electricity to salty water, iron based positive electrodes (even 316SS) dissolve iron into the water, making rusty water. You might try Joe's suggestion of carbon electrodes; platinum clad titanium electrodes should work too but are very expensive, and probably not affordable for steam inhaler. But even still, Khozem's warning might apply because, as the water is distilled away, any contaminants in the water become more concentrated and discolor it.

I'm unfamiliar with other areas of the world, but we used steam inhalers in the USA when I was a child more than 60 years ago (and probably before that), so there are dozens of expired patents you can read on the subject at uspto.gov which will offer food for thought. Good luck!

Regards,

A. Hi Alex. With our present technology, hydrogen is an energy storage mechanism, not an energy source. Whether the hydrogen is made available to the engine as a compressed gas, or in some sort of bricks/sponges, or produced on-board by electrolysis, it takes more energy to make it than is recovered when it is burned.

But although there is no such thing as free energy, there is certainly such a thing as not wasting it. For example, the main reason hybrid cars get much better gas mileage than gasoline-only cars is because energy is not wasted in braking. When you press the brake pedal on a hybrid, what actually happens (except in emergency or below 2 mph) is that the motor/generators connected to the wheels charge the battery. When you need to accelerate, energy stored in the battery is converted to mechanical power by the motor/generators; when you need to decelerate, mechanical energy (momentum) is converted back to electrical power recharging the battery.

The point of this discussion of hybrids is to note that the motor/generators can only charge the battery by converting momentum to electricity. While your alternator may spin freely when it's not connected to and charging a battery, the only way it can charge the battery is by putting a mechanical load onto the engine. Unfortunately, whenever electrical power is pulled from that alternator, it's at the cost of mechanical power from the engine or the car's momentum.

So, in theory at least, a hydrogen-powered car could generate hydrogen from electrolysis during the braking period the same way present hybrids & EVs charge their batteries from braking ... but it can't generate hydrogen for free -- only by slowing down the car or requiring the engine to put more power in.

Luck & Regards,

A. Hi Alex. There is no question that there are fuels which generate more power than gasoline. Every drag racer knows of nitro-methanol, and that 'gassers' cannot successfully compete against 'top fuel' contenders. There are apparently now even several brands of nitro injector kits for street vehicles.

But whether HHO, whatever that is, and in small quantities, can actually usefully increase power output or is merely a scam, sorry, I have no idea. Maybe others readers will comment.

Luck & Regards,

Thanks again Ted, be well.