Can Artificial Photosynthesis Solve Our Energy Problems?

For billions of years, nature has perfected photosynthesis — a process that uses sunlight to transform water and carbon dioxide into sugars. These sugars serve as the energy source for every living being on Earth, from bacteria to blue whales. Photosynthesis is, quite literally, the foundation of life.

But could we imagine recreating this process artificially — and making it produce other forms of energy instead of sugar? Many scientists believe so, and research into artificial photosynthesis is taking place across the world with exactly that goal: to generate sustainable fuels from sunlight, CO₂ from the atmosphere, and water. The same research is also underway at the Department of Physics, Chemistry, and Pharmacy at SDU.

“We’re not interested in making sugar, though. We want to make other kinds of fuel,” says chemist Gabriel Libanio Silva Rodrigues from the department.

In stead of gasoline

By fuel, he means for example ethanol, methanol, or methane — substances that could serve as practical alternatives to gasoline in regular cars.

“That means we could keep the infrastructure – for example gas stations - we already have for fuel, without having to rebuild everything around a completely new energy system,” he explains, adding:

“Ethanol, methanol and methane are only three of the most common molecules that we can produce, though, and the fuels may also be used in airplanes, ships, the chemical industry and so on, Rodrigues adds.

Works great in Nature, but …

Before we indulge in sweet dreams of filling up our cars with CO₂-neutral fuel made from sunlight, water, and air, let’s take a step back and look at what artificial photosynthesis actually is — and how far the research has come.

Photosynthesis not only produces the food we eat; it also creates the oxygen we breathe. In nature, the process is carried out by intricate enzymes that split water and CO₂ and recombine them into new compounds — sugars.

In the lab, however, recreating this process is very difficult. One of the biggest challenges is cost: so far, no research team has managed to produce meaningful amounts of sugar, methanol, or methane through artificial photosynthesis in an economically feasible way. The process still demands a lot of energy, and making it commercially accessible is not yet practical.

Efficient, but rare and expensive metals

Another hurdle is finding the right catalysts — the molecules that drive the reaction between sunlight, water, and CO₂ to form the desired fuels.

The candidates tested so far are often expensive and unstable, causing the process to stop after only a few runs. Molecules containing metals such as ruthenium, rhodium and platinum have shown promise because they can accelerate the reaction efficiently, but they’re too costly (because they are rare) and still tend to lose activity over time.

“The real challenge is finding cheaper, more stable, and more efficient catalysts that could form the basis for large-scale production of CO₂-neutral fuel,” Rodrigues explains.

Research outside the laboratory

Today, many chemists use computer modeling to search for new, potentially interesting catalysts — and this is also Rodrigues’s approach. He doesn’t work in the lab testing candidates in test tubes.

Instead, he runs simulations on the computer, which gives him the freedom to explore the entire field of chemistry — from organic to inorganic chemistry, and from physical to biological chemistry.

“I’m interested in developing computational methods that make it faster to find promising candidates without sacrificing too much accuracy. Right now, a precise simulation can take weeks or even months, so we have to strike a balance between speed and precision.”

Computer power might be the needed game-changer

Rodrigues will now spend the next two years working on this project at SDU. He is part of the SDU Climate Cluster’s GAIA program, which brings together young researchers from around the world to contribute to SDU’s climate-related research efforts.

His project is titled “From Natural to Artificial Photosynthesis: Breaking Down the Sun Mountain on the Shoulders of Computational Chemistry.”

“Computational chemistry might just be the game-changer that leads to a breakthrough in artificial photosynthesis. But I think we should see this as a long, collective journey — one where we gradually gather enough insight to one day make it all work,” he says.