Explore the dissolving boundary between science and science fiction with news from the front lines of discovery and imaginative speculation on how each one could change our world.
In 2011, scientists debuted an advanced solar cell they dubbed an “artificial leaf”. Like a real plant leaf, the playing card-sized device creates energy from sunlight and water. When placed in a container of water in bright sunlight, catalysts in the “leaf” split water into its components, hydrogen and oxygen, and releases them as streams of bubbles, which can be collected and used as fuel. With a single gallon of clean water, this device could provide a home in a developing country with enough electricity for an entire day. But one problem is that people in such countries may not have enough drinking water to spare. A recent improvement to the technology may correct this issue.
Earlier versions of the leaf required pure water, otherwise bacteria formed a biofilm on the leaf’s surface and eventually stopped its production. Now the leaf has the ability to “self-heal”: parts of the catalyst can disassemble, denying bacteria the smooth surface necessary to form a film. It can then re-assemble and continue splitting molecules. This could make the technology much more applicable in regions where clean water is already scarce.
An estimated 3 billion people on Earth live in areas without electrical distribution, and 1 billion lack reliable access to clean water. This latest improvement to the “artificial leaf” could make it a viable option for all of them. The leaf is made of cheap, abundant materials—silicon, cobalt, and nickel—and requires no external wires or circuits. It is also much less costly and complicated to use than conventional solar panels, making it a better solution for difficult conditions.
The artificial leaf compared to conventional electrical production systems is rather like a mobile phone compared to a phone booth. It’s small, portable, wireless, and offers accessibility in places that were previously unreachable. If mechanisms for harnessing the leaf’s chemical energy are made simple and affordable, it could drastically improve quality of life in developing regions. Additionally, it could reduce dependence on more environmentally destructive fuel forms in these areas, such as coal or fossil fuels.
Better yet, how about tweaking the “leaf” design for use as a water purifier? If it can split water into hydrogen and oxygen, effectively filtering out impurities, those gases could plausibly be reassembled into clean drinking water. Given that a seventh of the human population lacks reliable clean water, this application could potentially have an even greater impact than quick, cheap electricity.
On a more imaginative scale, the “leaf” could be a great solution in terraforming. Assuming a reliable source of water could be secured, the “leaf” offers an effective solution for powering critical electrical systems—life support, perhaps, or communication devices—without the hassle of installing generators or other bulky systems. It could power mobile scouting teams and even entire colonies. Easy, reliable power could be critical to success in a “developing world” of another sort.