Nano Solar Cells being Developed to Produce Hydrogen in Simple Plastic Bags

The ability to split water into its consituent elements of hydrogen and oxygen using electolysis has been known for over 100 years. This process can provide large amounts of hydrogen which can be used to power our homes and cars in a non-polluting and renewable way. However, traditional methods of electrolysis require highly purified water to ensure that components in the hydrolysis system do not become fouled up. In addition, an already-existing method of producing electricity is required to power the hydrolysis process itself.

Standard photovoltaic cells can be used to generate electricity to produce electrolysis, but this is an inefficient and expensive process. Instead, a company called Hypersolar is developing a way of mimicing the photosynthesis that plants use, by optimizing the process of hydrolysis at a nano-level.

The idea is to use tiny components of photovoltaic material, in self-contained nano-sized photoelectrochemical particles. These are integrated into small electrolysis particles which are covered in special encapsulation materials. The particles can be immersed under water where they will produce hydrogen automatically when exposed to the sun.

The company announced in May 2012 a working prototype of a small scale photovoltaic device, coated with their unique but inexpensive polymer coating to create a self-contained particle. The polymer coating protects the particle from corrosion like from acidic water or waste, thus enabling the particles to produce hydrogen from almost any water source without the need for purification. A demonstration video released by the company shows a small scale solar device, which has been placed at the bottom of an inexpensive plastic bag filled with waste water from a paper and pulp mill. Bubbles can be clearly seen floating up to the top of the bag.

One question that seems to have been raised by sceptics on the internet is that if hydrolysis produces both hydrogen and oxygen, surely these gas bubbles must be both. Therefore wouldn't the hydrogen and oxygen just recombine at the top of the bag and revert straight back to water? Not being a chemist, I had wondered the same myself. Apparently however, according to investigations I've done, the process of hydrogen and oxygen combining to form water is very slow. It's only if a spark or heat source is introduce that the two gasses will combine rapidly and explosively.

So based on this, it seems the top of the bag would contain a mixture of hydrogen and oxygen. The hydrogen would then need to be seprated from the oxygen. I'm not sure how Hypersolar do this but it's certainly possible, using membrane filtration for example.

Following Hypersolar's May demonstration, a further video was released in July 2012 using smaller sized solar devices, again immersed in water in a simple plastic bag. Waste water from Califoina's Salton Sea was used to further demonstrate the versatility of the cells. This new demonstration showed a complete system which appeared to show the hydrogen being extracted from the bag into a conventional hydrogen fuel cell to producing the electrical output to power a small fan and LED lights.

For their final systems, the company intends to use much smaller nano-sized photovoltaic particles, or what they call photoelectrochemically active heterostructure elements. If their hopes are attained, they could create the possibility of completely independent hydrogen production where stand-alone hydrogen production units can be used to replenish fuel cells without the need for a network of cross-country pipelines. Who knows, maybe one day we could all be creating some or even all of the hydrogen we need to power our cars and homes in our back yard.