Talk:Electrolysis of water/Archive 1

Archive 1

Industrial electrolysis and water quality

When electrolysis is done on a large industrial scale, how pure does the water have to be? Can you just pump water out of a typical river, or would that lead to rapid fouling of the electrolysis unit? Is common tap water pure enough? Or do you have to go to the other extreme, and subject the water to distillation, or reverse osmosis, before adding the electrolyte? Answers to these questions should certainly be added to the article.199.46.199.231 (talk) 00:43, 18 December 2008 (UTC)

Theoretical maximum efficiency

I'm removing this clause: " while the theoretical maximum efficiency of the electrolysis of water is between 80–94%." The link provided makes no such claim, and in fact gives these numbers for specific systems. It states on page 20: " Norsk Hydro Electrolysers (NHE) is today a leading producer of alkaline electrolysers. Some of NHE’s electrolysers have an efficiency of over 80%..... Efficiency factors for [polymer electrolyte membrane] electrolysers up to 94% are predicted." This is the only place in the article where electrolysis of water is mentioned... 70.179.20.157 (talk) 11:10, 1 August 2008 (UTC) (andy)

Dropped Information

I dropped and did not replace the following formulas during my major reorganization of this page:

• 2H₂O + 2e⁻ → H₂ + 2OH⁻ E⁰red = −0.83 V
• 2H₂O → O₂ + 4H⁺ + 4e⁻ E⁰ox = −1.23 V

I wasn't sure where to put them. If you see somewhere they'd fit, please do. --Corvi 04:57, 21 February 2006 (UTC)

questions on W.E. from an idiot

1. When DC current is applied to the water molecule, which bond is broken first, the hydrogen bond or covalent bond? I'm assuming the hydrogen bond because it is weaker(?)
2. How much current is directly needed to break both covalent bonds of H2O?
3. How much current is directly needed to break one hydrogen bond between water molecules? (or is it heat that breaks it?)
4. Is each hydrogen bubble produced via electrolysis the result of the DC current breaking one covalent bond of the H20 molecule? If not, how much hydrogen is produced per unit of current?

I am presently stumped on this, but I'm sure that as soon as I post this I will experience a palm-forehead bonding.

BonfireBuddhist 01:38, 13 January 2007 (UTC)

Calculation Questions

Should the last lines of the opening section ("The volume of hydrogen gas produced is therefore twice the amount of oxygen gas. Assuming equal temperature and pressure for both gases, the hydrogen gas has twice the volume of the oxygen.") instead state that the mole number and not the volume of hydrogen is twice that of oxygen and then by consequence of the ideal gas law (and the accompanying assumptions) the volumes of the two gases would be in a 2:1 ratio as well.

Hanjabba 06:37, 2 March 2007 (UTC)

Endothermic or Exothermic?

Is electrolysis of water endo or exo? —The preceding unsigned comment was added by 121.223.213.155 (talk) 11:24, August 22, 2007 (UTC)

Electrolysis of water is endothermic; energy is flowing through the water delivering energy. The result is the exothermic release of heat, as excess energy is shed in an attempt to re-establish homeostasis with the surrounding environmental temperature; the water can get rather hot, and actually in some poorly designed electrolyzers the water can begin to boil. Noah Seidman 16:13, 14 September 2007 (UTC)

Endo and exothermic process are targeted towards reactions that are best described through enthalpies. Electrochemical reactions are better described as galvanic (spontaneous or giving off energy) or electrolytic (nonspontaneous or energy consuming). Electrolysis of water is an electrolytic reaction and requires energy. Since that energy can not be delivered with perfect efficiency (the has an overpotential) extra energy is poured into the system and is manifested as heat.--OMCV (talk) 05:57, 7 April 2008 (UTC)

Removed Audio File

I removed the audio file from htis page because it is over one year old, and significant changes have been made to this article since then. It holds no relevance. —Preceding unsigned comment added by 208.49.176.178 (talk) 20:50, 23 September 2007 (UTC)

Anodes/Electrodes

We seem to have had several edits and reverts pertaining to the beginning of the section, which says "Hydrogen will appear at the cathode (the negatively charged electrode, where electrons are pumped into the water), and oxygen will appear at the anode (the positively charged electrode)." -- especially, the words "positive" and "negative" being switched around. There's also an accompanying graphic which would seem to imply that hydrogen will appear at the negatively charged electrode, and oxygen will appear at the positively charged anode. Anyone care to clarify? Mikaey (talk) 07:53, 19 November 2007 (UTC)

Hydrogen evolution takes place at the cathode, which is negatively charged. 2H+ + 2 e- -> H2 — Preceding unsigned comment added by 130.232.37.172 (talk) 07:27, 14 June 2012 (UTC)

In zero gravity

How is the electrolysis of water carried out in zero gravity or in situations where the electrolysis machine may be inverted? Is there a particular shape used to keep the oxygen and hydrogen bubbles separate when the machine is inverted and is a centrifuge used in zero gravity?

VegKilla (talk) 22:11, 19 December 2007 (UTC)

Methods for improving the efficiency of electrolysis

As is mentioned in the article, adding potentially free heat to the water will result in higher conversion rates. What other methods are used to increase electrolysis efficiency? What research has been done on the effect of electrode materials, electrode topologies, and brine/electrode chemistries? Does modulating the voltage across the electrodes have any influence? —Preceding unsigned comment added by Voxelman (talk • contribs) 18:13, 12 January 2008 (UTC)

Scientific fraud

To begin, I'm glad you will be willing to work on this page, Nseidm1. To begin with on this electrolysis of water page the concern is not directly the financial scam but the fraudulent information concerning electrolysis. I would direct you to Internal combustion engine#Engine Efficiency however I suspect the second to last paragraph in that section to have been installed by a sock puppet or one of your collaborators. The efficiency of an ICE is primarily dictated by the difference between the lower and upper temperatures of the engine as described by the Carnot cycle. For a terrestrial engine this means an ICE is limited by the upper thermal stability of the material used to make the engine. As a result most engines don't do better than around 35% at their max efficiency. In a well designed engine 99.9% of the fuel is combusted to H₂O and CO₂. The small fraction that isn't fully combusted ends up as trace quantities of CO and hydrocarbons. At the same time during combustion some of the nitrogen include in the fuel/air mixture is converted to NO_X. As stated before all of these trace exhaust materials are a fraction of a percent of the fuel combusted. A more complete combustion would not add a measurable effect to the systems efficiency for a well designed engine. Meaning no change in MPG. It is true that altering the fuel mixture (gasoline + another fuel) as well as the air to fuel ratio effects the concentration and relative ratio amounts of these trace exhausts. I am not surprised that a gasoline/H₂ mixture burns more efficiently (say 99.9% vs 99.99%). I trust there has been extensive studies into the gasoline/hydrogen fuel mixture since nearly every conceivable fuel mixture has been studied, thank you for identifying this literature. I would however, like to point out that most manufactures find it more efficient to add a catalytic converter rather than an exotic fuel mixture. The emission is a tangential point, the core interest is a drastic increase in fuel efficiency and that is the basis of the fraud. Just to address all the issues you mentioned the role of sludge popularized in TV commercial for various brand of gasoline is not an issue for a well designed engine using a well formulated fuel. I have include this information here as a supplement since it is in appropriate to include information on a page about water electrolysis. Please address any further concerns to this talk page.--OMCV (talk) 02:52, 23 April 2008 (UTC)

First to clarify, I am only Noah Seidman and have no sockpuppets. I only represent myself (I have no collaborators). I have edited these pages for a long time, and my knowledge and comprehension of the subject matter is continuously improving. I revert all the hype, and bad info inserted regarding fuel enhancement scams. I also wish to uphold the scientific integrity of wikipedia.

Some questions. Would an engine operating mostly 30:1 air/fuel ratios have better economy than an engine operating at 14.7:1? Since there is a limit on air flow through the intake system to achieve 30:1 ratios approximately 1/2 the fuel would have to be injected; 1/2 the fuel would entail an effect on economy. Am I totally of base here? Would fuel vaporization, prior to direct injection increase the potential economy of the engine being that only gasoline vapors are combustible? As the temperature of combustion decreases NOx production will decrease, therefore wouldn't operating an engine under ultra lean conditions reduce emissions the same way as running an engine rich? In an ultra lean burning engine what would the role be for a catalytic converter? My understanding of a catalyst is that it reduces the activation energy required for a reaction to take place; therefore encouraging the formation of dioxides from monoxides.

To elaborate on my role and intentions. I believe that the combination of fuel vaporization, hydrogen injection, and ultra lean burn conditions will allow an EC engine to operate slightly more efficiently, much more economically, emit less monoxides, and eliminate NOx production entirely. Fuel enhancement is more than just "hydrogen injection", its a combination of a variety of concepts with the intent to maximize the potential for a IC engine. I see no reason that an IC engine should be running under rich conditions; to me this is a waste of fuel in a cheap attempts to reduce combustion temperature. A large excess of atmosphere (lean conditions) will achieve the same temperature reducing effect, while also improving economy.

Also, automotive applications are not my favorite application, and I find it quite frustrating that I find myself involved in in depth debates on the subject. I want to apply the fuel enhancement concept to residential and power production applications, which I feel is much more viable although less applicable to the general public. I probably end up in automotive debates because it is the only engine that the general public is familiar with. Noah Seidman (talk) 03:37, 23 April 2008 (UTC)

As for being concerned about info in oxyhydrogen, hydrogen fuel enhancement and other articles. The vast majority of info regarding "fuel enhancement" is quotation from academic publication. There is little info in those sections from patents, and all bold statements are from third party academia. As you precisely pointed out efficiency cannot be effected much, which I always agreed with, but emissions and economy can be effected. The position I have always held is that "hype", and these scam marketing tackings (ie. run your car on water) are quite disturbing.

There is much academia that says the economy of an IC engine can be improved using the hydrogen fuel enhancement concept in combination with lean burn conditions. These publications should be the foundation of the information contained in Wikipedia regarding the subject. Noah Seidman (talk) 03:57, 23 April 2008 (UTC)

If I can presume your main point is that burning half the fuel doubles the economy. This is true if you get the same result however burning half the fuel releases half the chemical energy. The capture of that chemical energy is still governed by the Carnot cycle no matter how you dress it up. Your suggestions of using leaner fuel is comparable to replacing a six cylinder engine with a four cylinder. Economy improves but performance decreases. In addition if you concern is truly economy and not efficiency than many of your edits need significant revision.

Nothing you added here counters the fundamental points I made above. --OMCV (talk) 04:25, 23 April 2008 (UTC)

My intent is not to counter, it is to learn. Noah Seidman (talk) 04:42, 23 April 2008 (UTC)

The relevant description of the physical phenomenon was removed from the fraud section and substituted with a redirect to a product review Hydrogen fuel enhancement which is a prime example of the relevant fraud. The coverage of John Kanzius work may need rewording but the remainder of the information will be reverted to a form that is relevant and meaningful for a page titled electrolysis of water. --OMCV (talk) 01:14, 25 April 2008 (UTC)

Nicely reworded. My main intent on wikipedia is to establish a clear distinction between what can work and the gross perpetuation of fraud on the internet. I feel that we are effectively working toward this. Noah Seidman (talk) 02:32, 25 April 2008 (UTC)

Nseidm1 please use fewer edits when working on pages. Figure out what you are going to write and submit a single edit. This applies to all the pages you work on. In addition above you stated that you are learning this material and as a result you should be very careful with your editing. If you do feel compelled to make them it would be best for you to supply a rational for your edits on the talk page. As for the hydrogen fuel enhancement it is clearly a financially motivated advertisement with serious POV issues. Those POV issues should not migrate beyond that page.--OMCV (talk) 07:04, 26 April 2008 (UTC)

Section removed as unsourced WP:OR. A couple of links to youtube and news hype do not serve as sources. No doubt there are fraudulent commercial/consumer claims out there, but the content presented requires adequate sourcing and seems rather out of place in a general article on hydrolysis of water. I've added a see also link to Hydrogen fuel enhancement where the subject can be discussed at length. Quite simply, a long unsourced section here won't work. Vsmith (talk) 12:50, 26 April 2008 (UTC)

How much energy is required to produce a mole of hydrogen through the electrolysis of water?

In the 'efficiency' section it might be helpful to give as an absolute value the energy in kJ required for electrolysis of water, not just the efficiency as a percentage, in the context of the water fuel myth. The Oxyhydrogen article states that 241.8 kJ of energy is released for every mole of H2 and O2 burned. Does this mean that at least 257 kJ of energy is required to produce a mole of H2 by electrolysis (equivalent to the maximum efficiency of 94%)? Strayan (talk) 05:12, 31 July 2008 (UTC)

Articles for deletion nomination of Electrolysis system

I have nominated Electrolysis system for deletion. I do not think that this article satisfies Wikipedia's criteria for inclusion, and have explained why at Wikipedia:Articles for deletion/Electrolysis system. Your opinions on the matter are welcome at that same discussion page; also, you are welcome to edit the article to address these concerns. Thank you for your time.

Please contact me if you're unsure why you received this message.

I thought folks here might be interested in this.OMCV (talk) 01:17, 27 October 2009 (UTC)

Half reaction equations and potential of water electrolysis?

In Equations:

In the water at the negatively charged cathode, a reduction reaction takes place, with electrons (e⁻) from the cathode being given to hydrogen cations to form hydrogen gas (the half reaction balanced with acid):

Cathode (reduction): 2 H⁺(aq) + 2e⁻ → H₂(g)

At the positively charged anode, an oxidation reaction occurs, generating oxygen gas and giving electrons to the cathode to complete the circuit:

Anode (oxidation): 2 H₂O(l) → O₂(g) + 4 H⁺(aq) + 4e⁻

The same half reactions can also be balanced with base as listed below. Not all half reactions must be balanced with acid or base. Many do like the oxidation or reduction of water listed here. To add half reactions they must both be balanced with either acid or base.

Cathode (reduction): 2 H₂O(l) + 2e⁻ → H₂(g) + 2 OH^-(aq)

Anode (oxidation): 4 OH^-(aq) → O₂(g) + 2 H₂O(l) + 4 e⁻

Combining either half reaction pair yields the same overall decomposition of water into oxygen and hydrogen:

Overall reaction: 2 H₂O(l) → 2 H₂(g) + O₂(g)

However, I have learnt from my chemistry lessons (and several other websites use this too) that the following are the half-reactions: (numbers in square brackets are electrode potentials taken from Standard electrode potential (data page))

2 H+ + 2 e- -> H2 [0.0 V] Cathode

4 OH- -> O2 + 2 H2O + 4 e- [+0.40 V] Anode

Alternately,

2 H2O + 2 e- -> H2 + 2 OH- [-0.8277 V] Cathode

2 H2O -> O2 + 4 H+ + 4 e- [+1.23 V] Anode

Can anyone explain this discrepancy? Both sets of equations add up to the overall reactions as well.

However, strangely, if I add the electrode potentials up to obtain the electrode potential of the entire reaction, I get about 0.40V, which is different from the value of -1.23 V apparently given in the "Thermodynamics of the process" Section(?). In addition to this discrepancy, I don't get the info given in the section. What does E^o
_ox and E^o
_red mean? Also, while this might not be so relevant to this page, what is Gibbs free energy? I've read the article, but I don't get it and how it can apply here. Can anyone explain? 218.186.9.231 (talk) 14:40, 25 March 2010 (UTC)

Edit: Apparently, this got deleted because "it's not about improving the article". However, I disagree. While this is mainly due to my failure to understand what was in the article, it can very well be used to improve the article. I have seen a discrepancy in this article that may confuse many people who were taught with different half-equations. This shows that there is insufficient explanation in the article. Clearing this up will definitely help improve this article.218.186.9.231 (talk) 10:15, 26 March 2010 (UTC)

Please see your talk page User talk:218.186.9.231 page for an explanation.--OMCV (talk) 15:05, 26 March 2010 (UTC)

H₃0⁺

We learn in school that H⁺ can not exist in the nature. How would the half-reactions look like if we used H₃0⁺ instead of H⁺? --Smihael (talk) 15:11, 17 May 2010 (UTC)

Substitute a H₃0⁺ for every H⁺ and add a H₂0 to the opposite side of the reaction.--OMCV (talk) 05:10, 19 May 2010 (UTC)

See Hydronium פשוט pashute ♫ (talk) 07:29, 1 March 2011 (UTC)

Electrode choice

Please answer the following questions directly in the entry, or here - in which case I'll add them to the entry.

• What about graphite?(In my experements graphite crumbles quickly. Just in case it matters, in my test I used salt water. I've since come to prefer baking soda instead of salt because salt encourages rust. Both salt and baking soda, when dissolved in water, increase the water's conductivity, which increases production. Although baking soda doesn't increase the conductivity as much as salt, it is worth it since you're not constantly needing to replace electrodes. The graphite also seems to produce a great deal more clorine gas (from the salt) than metal electrodes ever did, I could smell it all over my garage.)
• What is the difference between the electrodes? What are the benefits / disadvantages of various materials?(Stainless steel is best. It resists rust and is far cheaper that platinum. I like to use old butter knives from thrift stores.)
• What about the electrode shape, does it have to do with amount of electrolysis occuring?(Surface area certainly matters. More area equals more conductivity, which means more production.)
• Is there importance in the distance beween electrodes?(If there is, it isn't much, as I have never noticed it.)
• What is the final verdict: Which side has the Oxygen and which the Hydrogen?(+ has oxygen, - has hydrogen.)
• Do you need to capitalize Hydrogen and Oxygen in English or American?( Sorry, I don't have an answer for this one.)

Thanks, פשוט pashute ♫ (talk) 07:26, 1 March 2011 (UTC)

REF #11+13

ref 11+13 do not appear valid anymore.Overseer19XX (talk) 17:26, 4 April 2011 (UTC)

Manner of electrolysis and production of either (2x) H2 and O2 or Oxyhydrogen / HHO / Browns Gas

the electrolysis (school experiment) picture at the top of the page shows no requirement (or gives no explanation) of separating the gases produced. Therefore, The actual Gas produced in this manner is Oxyhydrogen/HHO/Browns Gas and not as described in the opening paragraph >Electrolysis of water is the decomposition of water (H2O) into oxygen (O2) and hydrogen gas (H2) due to an electric current being passed through the water.NeiallsWheel (talk) 23:31, 17 March 2012 (UTC)NeiallsWheel

Questions - simple science experiments

I've done same research on this topic so far, but haven't seen anything concise that can help so I thought I'd pose some questions here. I'm trying to help my son complete a science experiment for 5th grade. That experiment is to demonstrate electrolysis of water using a 6v lantern battery and a salt solution (I am using filtered water and sea salt, 1 tbsp salt in 1L of water). I have to admit I thought the experiment would be easy for him, but it failed. The 6V battery generated plenty of hydrogen gas but no oxygen that we could discern. We next tried to use a 9VDC transformer powered by 110VAC and the results were similar. Finally I tried 110VAC directly and had success. My questions are:

1. The thermodynamics section seems to indicate the potential for the reaction might take place at <2V. Under what conditions and using AC or DC? Why did 6VDC and 9VDC fail to produce oxygen gas?
2. A substance is left in the salt water solution after the 110VAC (braided copper) wires are applied to the solution. What is this?
3. It seems that a significant power source must be used to generate oxygen and hydrogen? Does that make sense?

My apologies for what may be simple questions. (JT Pickering (talk) 16:23, 4 May 2008 (UTC))

This is really not the place, but you do note that if DC only produces hydrogen at one electrode, 110 V AC will simply produce hydrogen at *both* electrodes because of the nature of the alternating current? --Rifleman 82 (talk) 16:45, 4 May 2008 (UTC)

Sodium chloride will break down more quickly than the water will. If you're using sodium chloride for your salt, Chlorine gas is produced at the positive terminal (which is the anode for electrolysis), and I'm guessing that it's combining with your copper electrode to produce copper chloride. Meanwhile, you're producing sodium at your cathode (negative terminal), and that sodium is undergoing a replacement reaction with the water to produce Sodium Hydroxide and Hydrogen gas. This is just a guess; I'm not a chemist. I believe the section concerning the selection of an appropriate electrolyte should be expanded to include details of this sort. kevinthenerd (talk) 21:44, 14 June 2008 (UTC)

The oxygen may be combineing with the metal of the + electrode to produce oxidation (corrosion or rust). Try useing baking soda in the water instead of the salt as salt has corrosive qualities. P.S. Try useing stainless steel electrodes, such as old butter knives. These will resist rust and corrosion and are much cheeper than platinum. — WertMooMoo (talk) 08:52, 28 May 2013 (UTC) WertMooMoo (talk • contribs) 09:23, 18 May 2013 (UTC)

Interesting how things progress over the years. Your son is attempting this experiment in the 5th grade, we performed this in high school. I have my old high school science chemistry lab book from 1970. It gave 4 sources for DC power: 4 dry cells in series (~6 VDC), a 6 VDC lead acid storage battery, a 6-8 VDC rectifier or a 110 VDC lab outlet with an electric lamp in series to regulate the current (we didn't have the 110 VDC outlet, sounds pretty dangerous though :^{) ). The lab called for 10 ml of concentrated sulfuric acid to be slowly added with stirring to 600 ml of water. The reason for the sulfuric acid is to increase the conductivity of the water. The sulfuric acid is not used up in the electrolysis of the water. The apparatus used platinum electrodes and is exactly like the one described in the main article. (I can provide a drawing of the apparatus if needed) I did get a 2:1 ratio of hydrogen:oxygen with hydrogen at the negative eletrode and oxygen at the positive electrode. You should try to use platinum electrodes because I don't think that copper will produce the same results. Streichre 12:46, 27 June 2008 (CST)

Kevin was close on the subject but each half cell has its own overpotential and needs to be treated independently. I've included the pertinent half cells from the Standard electrode potential (data page).(May be a bit over complicated. See WertMooMoo's explanation above that begins, "The oxygen may be combineing."WertMooMoo (talk) 08:51, 28 May 2013 (UTC))

Half-reaction	E° (V)	Ref.
Na+ + e− $\rightleftarrows$ Na(s)	−2.71
2 H+ + 2 e− $\rightleftarrows$ H2(g)	≡ 0
O2(g) + 4 H+ + 4 e− $\rightleftarrows$ 2 H2O	+1.23
Cl2(g) + 2 e− $\rightleftarrows$ 2 Cl−	+1.36
H2O2(aq) + 2 H+ + 2 e− $\rightleftarrows$ 2 H2O	+1.78
S2O82− + 2 e− $\rightleftarrows$ 2SO42−	+2.07

So water needs to be reduced which also happens to be the semi-arbitrary reference point for the reduction potential scale. Thus the reduction of water happens at zero at pH 0 or -0.420 at pH 7 (via Nernst equation). Water is oxidized thermodynamically at +1.23 V for pH 0 or 0.81 V at pH 7 (via Nernst equation).

There is a small overpotential for the reduction of water but it usually reacts easy. Hydrogen is produced far before the electrode potentials become negative enough to reduce sodium cation to sodium mental. In the case of an acid electrolyte the reducing the acid's protons is the desire reaction.

The oxidation of water is a different story. Its a very complex process involving two water molecules and four electrons. As a result if there isn't a viable electrocatalyst like platinum to facilitate the reaction than the over will be high, up to a more than two volts. Even with platinum there is still an overpotential. So even if water should thermodynamically oxidize to O₂ at 0.81 V at pH 7 the kinetics are bad (high overpotential) it won't happen if something else can oxidize first. What I mean is if the kinetics (lower overpotential) are good enough for another reaction even though the thermodynamics are worse (more positive reduction potential for a oxidation) than it will happen before the thermodynamically favored reaction. There are a few things that can happen in the discussed setups: 1) the electrolyte can be oxidized for example producing chlorine from chloride (and then reacting with the electrode) or 2) you can partially reduce water via a two electron route to hydrogen peroxide which will make oxygen very very slowly. The advantage of H₂SO₄ as an electroylte is that it very hard to oxidize the highly oxidized SO₄^2- ion. Chances are in most high school set-ups perform the two electron oxidation of water to H₂O₂ than the electrode catalyzes the decomposition of H₂O₂ to make O₂. Takes more energy but no big loss in a demonstration. Copper, however, might not decompose H₂O₂. The short cutting to H₂O₂ is also a big problem with PEM fuel cells since the making H₂O₂ means they aren't pulling all the energy out of hydrogen and then the H₂O₂ corrodes many different components.--OMCV (talk) 17:51, 12 August 2008 (UTC)

Cleanup of efficiency section

I found the section on efficiency quite confusing, and in particular it was incorrectly using the HHV instead of the Gibbs free energy for efficiency definition. Some references were overly specialistic and others looked like self-promotion or "recentisms". BTW: yes I am an expert. 78.91.103.24 (talk) 15:24, 21 November 2013 (UTC)

PEM Efficiency

I think it is a mistake to have Wikipedia state that PEM electrolysis of 90% is possible. The source article(sponsored by BP) says:

Efficiency factors for PEM electrolysers up to 94% are predicted, but this is only theoretical at this time. Today, the efficiency factors for PEM electrolysers are lower than for the best alkaline electrolysers.

--Paulwesterberg (talk) 16:31, 2 December 2014 (UTC)

That was exactly how it was said in Bellona 2002 [1], now in 2014, 12 years later 2014 - Development of water electrolysis in the European Union Mion (talk) 09:22, 3 December 2014 (UTC)

Honjie Dai's system

I briefly mentioned Hongjie Dai's system, see http://news.stanford.edu/news/2014/august/splitter-clean-fuel-082014.html Honjie Dai's water splitter http://www.technology.org/2014/08/25/scientists-develop-water-splitter-runs-ordinary-aaa-battery/

Not sure though whether it's more efficient/less costly than Daniel Nocera's system, or Bob Boyce's electrolyser. Perhaps the latter 2 should also need to be mentioned.

2A02:A03F:12C7:F000:213:20FF:FE3B:A79E (talk) 09:11, 15 February 2015 (UTC)

→== OXYHYDROGEN not present in this electrolysis of water section? ==

To keep this acknowledgement simple, please refer to section 18 of this archive (2012)Talk:Electrolysis_of_water/Archive_1 https://en.wikipedia.org/wiki/Talk:Electrolysis_of_water/Archive_1 Amendments to this learning platform seem to include deletion/eradication of some very basic understandings of history & science

There is an oxyhydrogen page on Wikipedia Is there a date planned for its deletion too? NeiallsWheel (talk) 19:18, 17 October 2015 (UTC)NeiallsWheelNeiallsWheel (talk) 19:18, 17 October 2015 (UTC)17/10/2015

"Oxyhydrogen" refers to any mixture of H2 and O2. "Brown's Gas" is an archaic term for a 2:1 molar mixture of the same, and "HHO" is a fringe term used by the perpetual motion woo crowd. What is the actual proposal you are making for a change to this article? VQuakr (talk) 21:56, 17 October 2015 (UTC)

VQuakr Page reads *with my proposed addition* Electrolysis of water is the decomposition of water (H2O) into oxygen (O2) and hydrogen gas (H2) due to an electric current being passed through the water.

This technique can be used to make hydrogen fuel (hydrogen gas) and breathable oxygen;

• Also Oxyhydrogen (Wikipedia link) https://en.m.wikipedia.org/wiki/Oxyhydrogen

can be produced if the gases are not separated* currently most industrial methods make hydrogen fuel from natural gas instead.

VQuakr Article reads Use at Home Hydrogen can be made at home (often not for any purpose other than blowing up), most often with electrolysis of water. The phrase in brackets (often not for any purpose other than blowing up) should be deleted completely and instead a small explanation (below)complete with a link to this Wikipedia page

In this home surplus solar energy is used to create hydrogen, which is stored and utilized in winter through a fuel cell to create electricity https://en.m.wikipedia.org/wiki/The_Hopewell_Project

VQuakr I would also be editing the oxyhydrogen page With this link, and a relevant piece of text to update this educational community with an effective example of an another application for oxyhydrogen (the terms hydroxy and HHO are more commonly used names for oxyhydrogen) this is also a valid case for ensuring that pages for HHO, browns gas, and hydroxy, are commonly directed to the oxyhydrogen page.

Effect of hydroxy (HHO) gas addition on performance and exhaust emissions in compression ignition engines >Ali Can YilmazErinç UludamarKadir Aydin< http://www.sciencedirect.com/science/article/pii/S0360319910013595

In this study, hydroxy gas (HHO) was produced by the electrolysis process of different electrolytes (KOH(aq), NaOH(aq), NaCl(aq)) with various electrode designs in a leak proof plexiglass reactor (hydrogen generator). Hydroxy gas was used as a supplementary fuel in a four cylinder, four stroke, compression ignition (CI) engine without any modification and without need for storage tanks. Its effects on exhaust emissions and engine performance characteristics were investigated. Experiments showed that constant HHO flow rate at low engine speeds (under the critical speed of 1750 rpm for this experimental study), turned advantages of HHO system into disadvantages for engine torque, carbon monoxide (CO), hydrocarbon (HC) emissions and specific fuel consumption (SFC). Investigations demonstrated that HHO flow rate had to be diminished in relation to engine speed below 1750 rpm due to the long opening time of intake manifolds at low speeds. This caused excessive volume occupation of hydroxy in cylinders which prevented correct air to be taken into the combustion chambers and consequently, decreased volumetric efficiency was inevitable. Decreased volumetric efficiency influenced combustion efficiency which had negative effects on engine torque and exhaust emissions. Therefore, a hydroxy electronic control unit (HECU) was designed and manufactured to decrease HHO flow rate by decreasing voltage and current automatically by programming the data logger to compensate disadvantages of HHO gas on SFC, engine torque and exhaust emissions under engine speed of 1750 rpm. The flow rate of HHO gas was measured by using various amounts of KOH, NaOH, NaCl (catalysts). These catalysts were added into the water to diminish hydrogen and oxygen bonds and NaOH was specified as the most appropriate catalyst. It was observed that if the molality of NaOH in solution exceeded 1% by mass, electrical current supplied from the battery increased dramatically due to the too much reduction of electrical resistance. HHO system addition to the engine without any modification resulted in increasing engine torque output by an average of 19.1%, reducing CO emissions by an average of 13.5%, HC emissions by an average of 5% and SFC by an average of 14%. NeiallsWheel (talk) 02:09, 19 October 2015 (UTC)NeiallsWheel 

HHO is a fringe term; per WP:REDFLAG you need a lot more than one marginal source to add it to the article. I removed the recently added "blowing up" phrasing as unencyclopedic. VQuakr (talk) 04:56, 19 October 2015 (UTC)

And another sourced study

Performance and Exhaust Gas Analysis Of A Single Cylinder Diesel Engine Using HHO Gas (Brown’s Gas)[Download] C.Naresh, Y.Sureshbabu, S.Bhargavi Devi

http://www.ijer.in/ijer/index.php/explore/layout/issue-archive/volume-3/volume-3-issue-special1 NeiallsWheel (talk) 08:11, 19 October 2015 (UTC)NeiallsWheel NeiallsWheel (talk) 08:18, 19 October 2015 (UTC)NeiallsWheel

IJER is on Beall's list of predatory journals. Anything else? VQuakr (talk) 08:10, 22 October 2015 (UTC)

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why not use H2O<==>(HO-) + (H+) as first step?

1. standard reaction any where in pure water: H2O<==>(HO-) + (H+)
2. Reduction at cathode: 2 H+(aq) + 2e− → H2(g)
3. Anode (oxidation): 2 OH−(aq) → 1/2 O2(g) + H2O(l) + 2 e−
4. 2 and 3 lead 1 to the right direction — Preceding unsigned comment added by 240E:82:600:7E8E:21F7:7BD8:F092:3085 (talk) 03:43, 22 February 2019 (UTC)

Anodic/Cathodic similarities between galvanic and electrolytic cells

Hi Vquakr.....I appreciate your concerns. The anodic/cathodic similarities/relationships between galvanic and electrolytic cells can be a confusing subject but, in my opinion, worthy of discussing in order to convey a true understanding. I tried to simplify it as much as I could but this obviously remained unsatisfactory to you. Do you have any suggestions for further improvements or do you think it is totally unnecessary to begin with. — Preceding unsigned comment added by ChemMater (talk • contribs)

Hi ChemMater, and thanks for starting this thread. For anyone else's reference, the proposed edit under discussion is [2]. There are a number of editorial and concision problems with the proposed edit, but those aren't particularly important because I don't think the edit is necessary at all. What you are describing is not unique to electrolysis of water, so if more explanation of anode v cathode is needed in the context of electrolysis, it should be discussed at Electrolysis#Process of electrolysis, not here. VQuakr (talk) 01:36, 31 October 2019 (UTC)

Thanks. I agree that seems to be a very logical alternative...I am teachable...

Thermodynamics

The first paragraph in this section and the first line in the second paragraph actually work together and it would be better to not separate them. Specifically, where it is stated "it follows that..." is based on 237 kJ divided by [2 * (96485 C/mole)]. As written the "it follows that ..." is too far removed from the 237 kJ for it to be obvious how 1.23 V is obtained. I hope someone more comfortable with editing will fix this.

Please tryChidgk1 (talk) 17:51, 30 April 2023 (UTC)

Anyone like to expand with economics politics and industry?

https://www.iea.org/reports/electrolysers Chidgk1 (talk) 18:43, 30 April 2023 (UTC)