It is a small, thin, rectangular-shaped device. In a similar way to real leaves, the artificial leaf has the ability to absorb the energy of sunlight and directly convert it into a chemical fuel, which can then be used later as an energy source. The device does not need external wiring nor control circuits to operate; all it needs is to be placed within a container of water with exposure to sunlight. Best of all, the artificial leaf does this all without releasing any carbon dioxide into the air.
The significance of this innovation cannot be understated, as carbon dioxide is the biggest contributor to global warming. Turning that carbon dioxide into methanol would not only decrease the greenhouse gas emissions, but also provide a substitute for the fossil fuels which create them.
The inspiration for this new technology is based on the way plants use energy from sunlight to turn carbon dioxide into food. Yimin Wu, an engineering professor at the University of Waterloo, stated, “We call it an artificial leaf because it mimics real leaves and the process of photosynthesis. A leaf produces glucose and oxygen. We produce methanol and oxygen.”
The process works via a cheap powder known as cuprous oxide. The powder is created by a chemical reaction; four substances – glucose, copper acetate, sodium hydroxide, and sodium dodecyl sulfate – are added to water and then heated to a particular temperature. The powder starts off blue, then it slowly turns green, then orange, and then a distinct red after about an hour.
From there, the powder acts as a trigger for another chemical reaction. When the powder is mixed in with water, a beam of white light is directed at it with a solar simulator. The reaction produces oxygen and concerts the carbon dioxide within the water into methanol. The methanol is then collected as it evaporates once the solution is heated. “This is the chemical reaction that we discovered. Nobody has done this before,” said Yimin Wu, who has been with the project since 2015.
“I’m extremely excited about the potential of this discovery to change the game,” Wu went on to say. “Climate change is an urgent problem and we can help reduce CO2 emissions while also creating an alternative fuel.”
As with many new technologies, however, it is not yet complete. There is much more that needs to be done still. For one thing, in the initial testing run, the artificial leaf only captured 4.7% of the total possible hydrogen fuel available from the solar energy. Thankfully, upgraded versions of the device have achieved better results, reaching closer to 10% of the available hydrogen fuel.