Energy is critical to the survival of all living organisms. Photosynthesis, or the conversion of light energy into chemical energy, has been performed by plants and some forms of bacteria for millions of years to fuel their activities.
As the planet’s denizens search for ways to mitigate the impact of fossil fuels on the environment and search for new fuel alternatives which will be ready to replace the planet’s finite supply of oil and coal, artificial photosynthesis is increasingly being studied as a viable energy source moving into the future.
What is Artificial Photosynthesis?
Artificial Photosynthesis seeks to replicate the natural process of photosynthesis. The goal is to make fuel from solar energy, but scaled up to meet the energy demands of a modern technologically driven society.
While plants accomplish their tasks using chlorophyll to capture the needed sunlight, proteins, and enzymes that are then converted to energy, the challenge of artificial photosynthesis is in trying to oxidize water to oxygen to jump start the physical process that produces the desired chemical reaction. As such, research has concentrated on developing a catalyst to accomplish this goal, and the past decade has witnessed some promising developments in the field.
Developments in the Field
Ever since its foundation in 1994, the Swedish Consortium of Artificial Photosynthesis has utilized the research skills of leading academics at Lund University, Stockholm University, and Uppsala University for a multidisciplinary approach to unlocking the mysteries of artificial photosynthesis.
The opening decade of the 21st century has witnessed an explosion of academic interest and testing within the field. A 2003 discovery out of Brookhaven National Laboratory, identified an intermediate step that reduces carbon dioxide (CO2) to carbon monoxide (CO). It is hoped that this discovery will lead to better catalyst designs in the future.
With funding from the United States Air Force, MIT scholar, Daniel Nocera, and post doctoral fellow, Matthew Kanan, made a critical breakthrough in their Solar Revolution Project. They discovered that scarce and expensive elements such as ruthenium and rhenium that were being used as catalysts, could be substituted with the far more abundant cobalt and phosphate at a much lower cost.
Efforts to arrive at a cost efficient solution to artificial photosynthesis moved out of the academic laboratory and into corporate world in 2009, when Mitsubishi Chemical Holdings started their own program to develop the technology. Their stated goal is to use sunlight, water, and carbon dioxide as the building blocks from which plastics, resins, and fibers can be extracted for a host of industrial applications.
In 2012, Scientists from the Department of Chemistry at the Royal Institute of Technology (KTH), developed a molecular catalyzer that is capable of oxidizing water to oxygen at approximately the same speeds as natural photosynthesis. Researchers worldwide had never been able to reach speeds of 300 turnovers with a molecular catalyzer. Leading KTH scientists believe that this breakthrough makes it possible to convert solar energy to electricity more efficiently.
Electronics giant, Panasonic, also announced in 2012 that it had developed a simple and efficient artificial photosynthesis system that utilizes a nitride semiconductor as a photo-electrode for CO2 reduction. Using direct sunlight or focused light, the system accomplishes CO2 conversion at a world’s top efficiency of 0.2%, which is on a comparable level with real plants used for biomass energy.
Whereas previous efforts have relied on complex structures, the introduction of a nitride semiconductor as a photo-electrode is viewed as a simple and efficient structure, which presents significant promise for achieving scalability in real world applications.
Potential Future Impact
Wide spread adoption of artificial photosynthesis is still years away owing to the fact that it is not as cost effective as fossil fuels. That being said however, a host of advantages are anticipated by the perfection and widespread adoption of the technology. It promises to simultaneously fuel the next generation of aircrafts and freight lines while reducing our enormous quantities of carbon dioxide emissions, which have been identified as the leading cause of the greenhouse effect.
The implications for fueling the transportation sector are very promising. While current technologies favor the use of ethanol to power the movement of people and products, artificial photosynthesis promises several advantages. Unlike biomass energy, the use of artificial photosynthesis will not be in competition with arable land.
For those who dream of enhanced space travel, artificial photosynthesis holds the promise of producing a stable supply of food and oxygen that could fuel the growth of space colonies in the future. Both, the Mir Space Station and the International Space Station have already successfully used a water electrolysis system to glean oxygen from water, and recycled water from their station’s dehumidifier tube. Extrapolating forward, it is believed that a working artificial photosynthesis system will provide the building blocks for a self-sustaining atmosphere at the farthest reaches of the solar system.
Once the world realizes that the unsustainable nature of fossil fuels will not support their grandchildren in the same manner that it sustained their grandparents, the search for carbon-neutral energy will begin in earnest, and when it does artificial photosynthesis will be ready to deliver the goods without destroying the planet. The ability to capture solar energy and immediately convert and store it for later use is certainly a game changer in the search for a cleaner, safer planet.