The program is quite complicated
The program is quite intricate. Photosynthesis is arguably the most important biological process there has ever been. Aside from simply creating the climatic conditions that made multicellular life possible, photosynthesizing organisms continue to graciously provide our planet with the oxygen that basically everything needs to live. And yet, scientists are looking for ways to make photosynthesis even better; if they crack it, we could use photosynthesis to power stuff like cars.
You might remember the equation for photosynthesis from your freshman biology class: the process is relatively simple. Basically, plants take in sunlight, water, and carbon dioxide and turn that into oxygen and stored energy in the form of glucose. And while it’s the foundation for virtually all life on Earth, photosynthesis is surprisingly inefficient; plants are only able to store about one percent of all the energy they receive from the Sun.
But researchers know they can do better than that, so for decades they’ve been trying to create artificial forms of photosynthesis in order to power our whole world. Now you might be thinking, but isn’t that just a solar panel? Well, yes and also no. Solar panels soak up the sun’s rays to generate electricity, which is an immediate energy source resulting from the flow of charged particles. But photosynthesis makes something that stores energy. So think the difference between electricity and something like gasoline: gasoline stores energy within its chemical bonds and then releases that energy when it gets ignited, and takes up very little space to do so.
And while generating solar electricity is able to power our homes and cars, it can’t always substitute for combustible fuels, which provide an unbeatable combination of power and compactness. Roughly 40 percent of global transportation is incapable of being electrified; I mean, you’d need a pretty big battery to get a Boeing 747 off the ground.
So while solar panels generate electricity, the goal of artificial photosynthesis is to use solar energy to produce usable fuel, which is done by splitting apart water molecules just like plants do. This basic design for artificial photosynthesis has existed since 1998 and even back then it was way more efficient than Nature’s version. However, in basically all the designs we’ve ever had for the process, it can either be durable, efficient, or cheap, but never all three at once, which is a big part of why we haven’t been using artificial photosynthesis much so far.
But if we do manage to make the process cheap and efficient, what could it be used for? Well, one type of fuel that researchers want to make is hydrogen, which burns cleanly, is zero carbon, and could be used to power future combustion engines or fuel cells. However, hydrogen gas is pretty scarce and is still mostly derived from fossil fuels. But we can make hydrogen fuel using a system called an artificial leaf.
These pseudo leaves utilize a design that features two electrodes immersed in a water-based solution called an electrolyte. The electrodes each gather energy from sunlight and use that energy to split the water into hydrogen and oxygen. This is a tricky process, not only generating the gases, but keeping them separate from each other. Hydrogen gas is very flammable and can full on explode in the presence of oxygen.
But the biggest problem often involves that liquid electrolyte we discussed earlier. That’s because water has a tendency to corrode the electrodes, and as you might imagine, that’s not great for the performance of electrodes. Most devices that use these liquid electrolytes could only function for less than a day before their electrodes would be completely corroded and need replacement.
But in 2018, researchers at the Joint Center for Artificial Photosynthesis in California made a major breakthrough for keeping their equipment in Tip-Top shape. Very basically, they used a solid electrolyte instead of the usual liquid kind and only fed water vapor into the system. Without the liquid electrolyte, the risk of corrosion went way down.