# Mining waste for cheaper hydrogen fuel production

Staff Emeritus
Summary:
feldspars, aluminosilicate from mining waste may be combined with selected, expensive metals, e.g., Pt ($1450/oz), Ir ($1370/oz) and Ru ($367/oz) or cheaper Co ($70,000/t), Ni ($26,000/t) and Fe ($641/t) to form effective 'water splitting' catalysts
Water splitting reactions that produce hydrogen are triggered using rare platinum ($1450/ounce), iridium ($1370/ounce) and ruthenium ($367/ounce), or cheaper but less active metals—cobalt ($70,000/ton), nickel ($26,000/ton) and iron ($641/ton).

Professor Ziqi Sun from the QUT School of Chemistry and Physics and QUT Centre for Materials Science and Dr. Hong Peng from the School of Chemical Engineering at the University of Queensland led research to create a new catalyst using only a small amount of these reactive metals.

They combined them with feldspars, aluminosilicate rock minerals found in mining waste that Professor Sun said some companies pay about \$30/ton to dispose of.

In the experiment, featured on the August cover of Advanced Energy & Sustainability Research, the researchers triggered a water splitting reaction using heated-activated feldspars nanocoated with only 1–2 percent of the cheaper reactive metals.
https://phys.org/news/2021-09-ingredient-cheaper-hydrogen-fuel-production.html

"Water splitting involves two chemical reactions—one with the hydrogen atom and one with the oxygen atom—to cause them to separate," Professor Sun said.

"This new nanocoated material triggered the oxygen evolution reaction, which controls the overall efficiency of the whole water splitting process," he said.

Professor Sun said cobalt-coated feldspar was most efficient and optimizing the new catalysts could see them outperform raw metals or even match the superior efficiency of platinum metals.

Andrew Mason, berkeman, 256bits and 2 others

Andrew Mason
Homework Helper
Very interesting. Just a few comments:

Are there not other, possibly cheaper, processes other than electrolysis? How about high temperature thermo-chemical processes using solar furnaces, for example?

The need for a non-carbon energy dense chemical fuel is going to become more and more pressing as the world realizes the we will eventually have to eliminate combustion of sequestered hydro-carbon. Some things will continue to need a chemical fuel source. It is going to be hard to develop electric aircraft, for example.

Hydrogen seems to be a very good fuel alternative. I was a bit surprised to see that Hydrogen has about 3 times the energy density (energy/unit mass) of diesel fuel.

AM

Bystander
Homework Helper
Gold Member
I was a bit surprised to see that Hydrogen has about 3 times the energy density (energy/unit mass) of diesel fuel.
One is less than twelve.

berkeman
Mentor
One is less than twelve.
Wakarimasen...

I was going to try to be more polite, and say "Lo siento, wakarimasen", but I was worried that might break Google Translate...

Staff Emeritus
Wakarimasen...
Atomic mass H = 1, although H2 = 2, and C = 12.

berkeman
Mentor
Atomic mass H = 1, although H2 = 2, and C = 12.

Whelp, that clears things right up. Guess I should have paid more attention in chem class. Bueller?

Astronuc
Andrew Mason
Homework Helper
One is less than twelve.
Material .................Specific Energy (MJ/kg) (combustion)

Hydrogen ..............141.86
Methane ...................55.6
Gasoline ....................46.4
Diesel fuel.................45.6

See: https://en.wikipedia.org/wiki/Energy_density and sources cited therein.

Last edited:
berkeman
Ygggdrasil
Gold Member
Hydrogen seems to be a very good fuel alternative. I was a bit surprised to see that Hydrogen has about 3 times the energy density (energy/unit mass) of diesel fuel.
It's important to note that hydrogen's numbers fall off a cliff once you consider the weight of the tanks needed to safely store the hydrogen. For the wikipedia source you cited above:
High-pressure tanks weigh much more than the hydrogen they can hold. The hydrogen may be around 5.7% of the total mass,[19] giving just 6.8 MJ per kg total mass for the LHV.

Of course, future technological developments may be able to change this. However, because of storage issues, I think hydrogen is less likely to play a role in transportation than in large scale power generation, where hydrogen could be a good solution to store excess energy from the grid for use later.

NTL2009 and Andrew Mason
Very interesting. Just a few comments:

Are there not other, possibly cheaper, processes other than electrolysis? How about high temperature thermo-chemical processes using solar furnaces, for example?

The need for a non-carbon energy dense chemical fuel is going to become more and more pressing as the world realizes the we will eventually have to eliminate combustion of sequestered hydro-carbon. Some things will continue to need a chemical fuel source. It is going to be hard to develop electric aircraft, for example.

Hydrogen seems to be a very good fuel alternative. I was a bit surprised to see that Hydrogen has about 3 times the energy density (energy/unit mass) of diesel fuel.

AM
What about in cars. The suggestion that has been brought up is way to big and cumbersome. I am all for getting into the hydrogen economy. The cheaper the catalyst the sooner the pollution will go down.