Re:Solar-driven water splitting at 13.8% solar-to-hydrogen e...
by lazide on Thursday November 18, 2021 @05:39PM
(#29271528)
To answer your question regarding commonality/ready availability -
Carbon, Nitrogen, and Iron are cheap and easy (you’re likely within body length of a large quantity right now). 32% of the earths mass is estimated to be Iron. $1/lb or less in massive quantities.
Nickel and Molybdenum are slightly harder to find, but not by much - nickel makes up 1.8% of the earth by mass and is a reasonably common metal in everyday manufacturing. It’s currently at $3.97/lb spot price at tonne quantities. Moly is in everything from greases to steels, and while typically not used in large bulk quantities alone, is available for such [https://tradingeconomics.com/commodity/molybden] at looks like $23/lb give or take.
So all commonly available elements, albeit (nanotubes) not necessarily in the form desired just yet.
> The trimetallic NiFeMo electrocatalyst takes the shape of nanometer-sized flakes anchored to a fully carbon-based current collector comprising a nitrogen-doped carbon nanotube network, which in turn is grown on a carbon fiber paper support. This catalyst electrode contains solely Earth-abundant materials, and the carbon fiber support renders it effective despite a low metal content.
I don't know anything about chemistry so I'll have to take their word on the fact that the elements they use are abundant.
The two concerns for area are:
1) The cost of panels to cover the area
2) The cost of the area itself, and the availability of a ton of empty space in a convenient location
If they are using abundant materials, the first is not as much of a concern, compared to photovoltaics. Since they are producing some sort of fuel rather than directly producing electricity, transmission efficiency is not really a concern*. So maybe we could plop a bunch of these things down in some sunny middle-of-nowhere desert.
* I guess is we consider vehicles to transport fuel, which must themselves burn fuel, to in some sort of abstract sense be part of the transmission efficiency, this computation could be pretty complicated.