It turns out that one of the great scientific challenges for this century will be the generation of energy in
an environmentally benign and sustainable way.
And this means, really, that it has to be from the sun.
I’ve been working in this area for close to two decades and there are different parts to the interest that I have.
One is, of course, on compounds that will absorb light.
A quantum dot, or a semi conducting nano-crystal is a tiny chunk of semi-conductor material.
They’re important because they have properties of large materials. For example, they’re crystalline, they’re robust,
but they also have properties of molecules in that you can put them into solution and
work with them using very inexpensive techniques.
The nano-crystal will absorb what’s called a photon of light and an electron gets excited.
We engineered these nano-crystals to actually take that excited electron and have it leave the nano-particle,
hop onto a nickel ion, once two electrons are on that catalyst, two protons will come over,
absorb those electrons and go off as a hydrogen molecule.
For making hydrogen out of protons in this way, people have typically used platinum catalysts and other catalysts that are
made from expensive metals it would be much more sustainable if we used metals that were more abundant on the Earth,
lower cost, and lower toxicity. Often those metals are ones like iron and cobalt and nickel.
Between Pat’s knowledge of generating inexpensive catalysts, and Rich’s knowledge of the energy,
and our knowledge of the nano-crystal,
to put all the pieces together to make this kind of catalyst
using the robust light harvester, which is inexpensive.
The work that we have right now, using the quantum dots, these give us unprecedented levels of activity.
Whereas before we might be talking about 100 or 1000 turnovers of hydrogen per molecule of catalyst,
we’re talking about 500,000 to 1 million turnovers at this point.
Hydrogen is important because we already have cars that run on hydrogen; fuel cell cars.
And they produce water instead of producing harmful emissions, like carbon monoxide, carbon dioxide.
So really from the point of view of having something that’s sustainable for millions of years.
We have sunlight, which is sustainable, water, which is sustainable, and hydrogen, which you can burn in a clean way.
This definitely adds to the promise of creating a new system for hydrogen production.
And not only does it lead to the promise of it happening, it leads to the promise of being able to do this
in an inexpensive way that doesn’t use more of the world’s resources than we need to.