Scandium-doped TiO₂ boosts photocatalytic water splitting efficiency
OK.
The novel material demonstrated an apparent quantum yield (AQY) of 30.3%, which measures the percentage of photons that lead to useful water splitting, and a solar-to-hydrogen (STH) efficiency of 0.34%, which indicates the percent of solar energy converted into hydrogen energy. Both values set new benchmarks for TiO2-based photocatalytic overall water splitting under ambient (non-pressurized, non-heated) conditions.
Super. But is that a lot? Obvs, relatively it’s a lot. But is that anywhere close to anything anyone would want to use? Eg, does it approach, or beat, the performance of light/’leccie/electrolysis?
Also, for anyone who actually does science, if this works then try an Sc/Li doped TiO2. And also play with Li/Sc/Zr doping. Not for any particular reason other than that when alloying metals that’s what we do because of the way the atoms nicely fit together. So, why not?
Catalysts usually shouldn’t fit too well. It’s the odd shaped holes where the magic happens.
I don’t get why the first number is so high at 30.3% when what really matters is the 0.34% energy efficiency which is very low.
Conventional PV based solar to hydrogen energy efficiency is 12.6% so ~40 times better.
@Andyf
Only certain energies of photon will be any good to cause the reaction. So they’re successfully using 30.3% of the “right kind” of photon. Of course, sunlight has a full spectrum of photon energies, so the ~99% that are useless for this reaction aren’t counted in the AQY.
So this counts as cool and interesting, but unless it can be layered and allow the 99% of “other” photons to pass through and be used elsehow, it’s probably not going to be terribly useful as it stands. And given TiO2 is the colourant used in white paint, the chances are it’s going to scatter everything else quite badly.
I’ll have to dig out the paper I wrote on non-conventional electrolysis back in the 1990s, but never tested due to not having suitable equipment.
Ah! Chinese scientists! I’d read this as a fiendish oriental plot to encourage the West to develop a “hydrogen energy economy” & finally fuck themselves altogether.
Tut, tut BiS.
I didn’t know anyone else thought like me!!!
Mmmmm.
So how are the hydrogen and oxygen physically separated, once the water molecule is broken by the photon?
In conventional electrolysis, this is by the pyhsical placement of the electrodes. In this catalysis process….do you generate a hydrogen/oyxgen micture then? What could go wrong?
(Cue Basil Brush).
At 0.3%, that’s maybe 1W per square meter. But hydrogen at atmospheric pressure, so useless. You need to throw away atleast half to run a compressor and generate high pressure hydrogen that can, in dreams at least, be stored.
An interesting research result on catalysis, but doesn’t appear to have any practical use.
I’m reminded of a Desmond Bagley thriller, set in Iceland (title I cannot remember), where the object is to allow the Russkies to capture a ‘secret’ device, that they will then waste all the research on…bit like doing the crossword…
I do remember the Calvados.
Yield aside, which isn’t …bad… for a lab experiment, this setup has one crucial flaw…:
It doesn’t separate the H2 and O2 generated…. A tad important when you work with something so volatile…
It’s interesting enough, but “Needs More Work” is most definitely on the table here.. Cholic mixtures have a tendency to be…. temperamental…
@Tim the Coder
Is it Running Blind?
I remember that plot twist on TV, and that novel was turned into a miniseries.
It rings a bell because I fear the ambulance service may be trying a similar thing on me.
They’re forcing me to go to Court to make them release evidence about Mrs Nerd’s death. I’m hoping that means the evidence is useful. However, I wouldn’t put it past them to force me to do it for something innocuous, just to waste my time.
@CJNerd
That’s the one! Thank you. The title was like a dodgy tooth. Just nagging, until resolved.
Tim the Coder,
There’s also Charlie Stross with his short story “A Tall Tale”, where – supposedly – the US tried to trick the Soviets into using lethally dangerous rocket propellants…
@Jason Lynch
Oooh. Thank you. I shall go searching…I have a wodge of Charles Stross somewhere, I’ve never got around to.
@Tim the Coder,
Available as a freebie here.
Alas, your link doesnt work or hover over reveal. Could you try again please?
Found it via wikipedia. Very entertaining. Loved the John Clarke references. FOOF!
Thank you.
Nice that people advice each other on Fiction…
Thing is… lab experiment, commercial value debatable…
Thing is…. the jump in efficiency is just about the same as exchanging cyanide for magnesium in “chlorophill”..
Can peeps keep Conspiracy out of actual Science? ( and yes… this classes as such…)
Not quite “Adults are Talking….” but this one… Got a nephew studying “Material Science” at the same Uni that gave us the CD player get back to me on this one for …once a year-ish….
It does move some goal posts… This, as the song goes, Is Not A Love Song… It opens roads…..
Jason: I think the stuff the Soviets were using long after the US went to solid fuel was pretty lethal anyway. I don’t think I would like to be dissolved in RFNA…
Nope… it’s worth it… Depends on the mechanism, and what you do with it, but this crystal can produce free Oxigen radicals at Human conditions, just wilh light and water.
That alone is worth it… It produces the most agressive substance known to Man, capable of reducing *anything* to ashes… By baking it in the Sun…
Might not be useful for energy generation, but as for getting rid of Nasty Stuff, yes… I can see Potential…..
It’s basically the same as the coating they put on self-cleaning double glazing.
Very fine Titanium dioxide to cause oxygen radicals to remove dirt.
But original comment remains: if using it to split water, how do you keep the H and O separate so no big bangs?
@Tim the Coder
Looks like it’s available as a freebie here.
The vaunted “hydrogen economy”?
The hydrogen (in whatever form) has to be burned is a useful manner, in an engine or something else.
This is the societally useful energy on which growth can be built.
How much energy and infrastructure is needed to split, gather, compress (to very considerable pressures)/liquify , store, transport etc etc?
In the magical byzantine city of grift, capital and spiritual center of powerpoint land, none whatsoever (which, alas, is the problem).
I’m not being negative, just realistic.
This “hydrogen economy” is just milk float 2.0. Another cart before the horses ideology.
Is that the “oxidises anything: glass, asbestos, research chemists….”
Sorry but this seems to be the sort of thing that comes out of giving universities research grant money. All very interesting but. If you want hydrogen gas, why not electrolysis using solar panels? Or you can get C+H compounds from sunlight via algae. Both current state of the art. Why spend all that money trying to make this shit work?
Always worth remembering. The primary reason for research is to line academics’ pockets.
If you want it as a printed freebie, it’s available here: reactormag.com/a-tall-tail/
Of course I’m sure that anyone who was really interested has long since found this out.
>But original comment remains: if using it to split water, how do you keep the H and O separate so no big bangs?
Flow the gas mixture through something that preferentially binds with oxygen? And ideally that you can keep cool enough that it doesn’t ignite the H2/O2 mixture;)
>If you want hydrogen gas, why not electrolysis using solar panels?
There’s an interest in being able to plop an otherwise ‘inert’ block down and let it scavenge energy from the environment. Granted, an actual operating machine is probably going to need power for all sorts of auxilliary machinery (pumps at a minimum) making the whole thing moot. And you can repurpose the energy from solar panels to other things if you need to . . .
And there’s just research for research’s sake – you never know when you might come up on something world-changing.
Finally, ‘science writers’ rarely really know the science, let alone engineering, and hype things up because that’s what they get paid for. Regular journalists are even more ignorant.
@Agamammon Something that has even more affinity for oxygen than hydrogen?
Ummm… not impossible, but… ummm… let me hide behind these blast-proof doors before you try that… 😉
>Something that has even more affinity for oxygen than hydrogen?
It doesn’t need more affinity, just a lower activation energy. The Hydrogen is already removed from the Oxygen, so we’re not talking about some kind of Thermit process.
Aye. Powdered sodium would work. 🙂
Sigh. If something has more affinity for oxygen than hydrogen, then it will exist in an oxydised state anyway. So you will need to use lots of energy to de-oxydise it, so you can use to separate the oxygen from the hydrogen.
Add perpetual motion and it may just work, just ask Rachel from Accounts to repeal the laws of thermodynamics, job’s a goodun.
An extremely fine membrane might work, hydrogen being so small and all that. But it’s bound to clog up over time leading to a build up of unseparated gas. Boom.
more affinity for oxygen than hydrogen
Or more affinity for hydrogen than oxygen?
Fluorine could be enormous fun.
‘So how are the hydrogen and oxygen physically separated, once the water molecule is broken by the photon?’
Burn them; let them burn. It will give you a solar candle. Yeah, use sunlight, with some losses, to make light. Everyone will have one on their mantel.