Researchers at Forschungszentrum Juelich, Germany designed a photoelectrochemical water splitting device which is the first of its kind to produce flexibility, compatibility and most of all scalability for efficient production of hydrogen as renewable fuel.
What is artificial photosynthesis?
Artificial photosynthesis refers to any process usually chemical, which replicates natural photosynthesis to convert sunlight, water and carbon dioxide into carbohydrates and oxygen. Artificial photosynthesis refers to any process that can capture energy from sunlight and store it in the form of chemical bonds in a fuel. Photoelectrochemical water splitting devices convert water into hydrogen ions and oxygen.
Scientists at Forschungszentrum Juelich, Germany have developed a compact design for artificial photosynthesis that is scalable. The scalable size of the design and concept is flexible even upto the materials used. Their findings have been published in the journal Nature Communications. Solar and wind power are already receiving much attention as sources of renewable energy. Harvesting energy from these sources and efficient storage technologies need to be developed.
Photoelectrochemical water splitting
It is one such technology that focuses on harvesting energy from sunlight to split the bond between water molecules to produce oxygen and hydrogen ions as fuel that must be stored in cells. The technology basically employs a solar cell and electrolyser. Hydrogen as fuel has been attaining considerable attention in recent years.
While the theory of photoelectrochemical water splitting remains clear there is a need for realistic design and technology that must be compact yet scalable. This technique has been limited to laboratory scale until researchers at Juelich stepped up to the task of making it scalable.
Unique design by Juelich Institute
Researchers at the Juelich Institute of Energy and Climate Research designed a unique, compact and complete technology in a self contained system at low cost and with easily available materials. The design covers a surface area of 64 square cm and appears relatively small. Its flexible design can be repeated and continuous repetition of the basic units can be used to fabricate a system to cover greater areas. The basic unit itself is composed of several solar cells that are connected by special laser technique.
The unique design of the basic unit with its cells being connected in ceries enables a single unit to reach a voltage of 1.8 volts for hydrogen production. It provides greater efficiency than the lab scale experimental models.
The present solar to hydrogen efficiency of the prototype unit is 3.9% and although it doesn’t sound like much it is the first of its kind and only drafted complete facility. The researchers defend the 3.9% efficiency by comparing it to the efficiency of natural photosynthesis that achieves only 1%. The researchers are hopeful that they can soon increase the efficiency to 10% by employing conventional solar cell materials. They may even consider employing a novel class of hybrid materials called peroskites that can possibly achieve an efficiency of 14%.
The major advantage of this piece of work lies in the ability to optimize the two main components separately; the two main components being the photovoltaic portion and the electrochemical portion. The photovoltaic portion produces electricity from sunlight and the electrochemical portion uses the electricity to split water. The technology has already been patented by the Juelich researchers as it is also applicable to all types of thin film photovoltaic technology and electrolysers.