With the electric vehicle revolution practically at our doorsteps, now would be a good time to accelerate the global renewable energy transformation. After all, we don’t want all those Cybertrucks hauling stuff around on fossil fuel-sourced electricity, right? A research team at Brookhaven National Laboratory in New York has come up with a nature-inspired solar power solution, one that could spark joy in the hearts of hydrogen and battery EV fans alike.
Solar Power Device Inspired By Plants
If you’re already thinking that “nature-inspired solar power” leads into something like artificial photosynthesis, that’s just about right.
Solar power is primarily associated with photovoltaic or thermal collection technology, but there is also a third wave of technology bubbling up to the surface, which mimics the process by which plants absorb and convert sunlight.
Loosely speaking, the result is to “split” water to produce hydrogen gas, which can then be used as a zero emission fuel.
Artificial photosynthesis is a bit more involved than conventional water-splitting. In a conventional system, an electrical current is generated offsite (ideally with solar power or other renewable energy), then introduced to water. In artificial photosynthesis, the water itself becomes the host for a photoelectrochemical reaction powered by sunlight.
The Brookhaven Solar Power Solution
If this all sounds like early stage research, well, it is. Artificial photosynthesis has a long way to go before it can hit the mainstream like PV cells and thermal collection.
For now, it’s all about the breakthroughs.
As explained by the folks at Brookhaven, the new breakthrough involves strategically deploying light-absorbing dyes, called chromophores, to break the chemical bonds that hold water molecules together.
The researchers combined catalysts and chromophores in such a way as to double the efficiency of the process. The ramped-up system provides a more effective platform for follow-on R&D.
In other words, don’t go looking down Aisle 12 of your local Walmart for that portable photoelectrochemical machine just yet, but keep an eye out for research that builds on the Brookhaven process.
How Does It Work?
The tricky part behind artificial photosynthesis (well, one of them) is to get the catalyst to activate the chromophore, without dragging electrons from the chromophore back to itself.
If all goes according to plan, the catalyst can then “steal” electrons from the water molecules, and that’s what makes the water molecule split apart.
Here’s the explainer from Brookhaven (break added for readability):
“The new approach uses molecular “tethers”—simple carbon chains that have a high affinity for one another—to attach the chromophore to the catalyst.
“The tethers hold the particles close enough together to transfer electrons from the catalyst to the chromophore—an essential step for activating the catalyst—but keeps them far enough apart that the electrons don’t jump back to the catalyst.”
Got all that?
For another way to look at it, consider the difference in speed between the movement of electrons and the pace of a chemical reaction.
In a press release describing the new system, lead Brookhaven chemist Javier Concepcion explained that “electrons move fast, but chemical reactions are much slower.”
“So, to give the system time for the water-splitting reaction to take place without the electrons moving back to the catalyst, you have to separate those charges,” he said.
In addition to breaking water molecules apart, the Brookhaven system is also designed to nudge the freed-up hydrogen ions together, to form hydrogen gas.
Why Renewable Hydrogen Is Good News For EV Fans
As for the significance of the new breakthrough, let’s hear from Concepcion again.
“One of the most important aspects of this setup is not just the performance, but the ease of assembly,” he said. “Because these combinations of chromophores and catalysts are so easy to make, and the tethers give us so much control over the distance between them, now we can study, for example, what is the optimal distance.”
While they’re busy working on that, last week CleanTechnica spoke with Mathias Lelievre, CEO of the clean tech firm ENGIE Impact, about accelerating the pace of global electrification.
Lelievre foresees that renewable hydrogen (meaning conventional water-splitting, for now) could be a “massive game-changer” that enables energy storage to ramp up at scale, potentially fostering more rapid growth in solar power and other renewables.
The energy storage aspect is important because millions of battery EVs are set to hit the road within the next several years. They will be competing with each other for grid space, and they will also be competing with all-electric buildings and electrified industrial processes. Energy storage — and lots of it — is the key to managing demand and providing other grid services in an all-electric economy.
Stay tuned for more insights from Mr. Lelievre.
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Renewable hydrogen process developed by Brookhaven National Laboratory (screenshot via YouTube): Stony Brook University graduate student and study coauthor Lei Wang.