FAQ

Frequently Asked Questions

General

How does artificial photosynthesis compare to steam methane reformation?

Most of the hydrogen used today is made with steam methane reformation. Steam methane reformation also produces a tremendous amount of carbon monoxide and carbon dioxide. Without carbon capture and sequestration, steam methane reformation is one of the dirtiest methods for producing hydrogen. But it does scale well, provided you have a lot of capital to throw at production, which is why most hydrogen is produced this way. However, fifty percent or more of the cost per kilogram is energy, in the form of natural gas.

Artificial photosynthesis uses 40% less energy per kilogram when electricity is the light source. When powered by direct sunlight, the energy cost is nearly zero. And artificial photosynthesis does not create carbon, so the related carbon capture and sequestration costs don't apply.

How does artificial photosynthesis compare to electrolysis?

When powered by dedicated renewable electricity sources, electrolysis produces hydrogen without a carbon footprint. However, fifty percent or more of the cost is energy, in the form of electricity.

Artificial photosynthesis uses 40% less energy per kilogram when electricity is the light source. When powered by direct sunlight, the energy cost is nearly zero. While both processes use water as the feedstock (input from which hydrogen is formed) electrolysis produces hydrogen and oxygen, which must be separated in some cases. Artificial photosynthesis creates hydrogen and hydrogen-peroxide (a gas and a liquid) that self-separate.

Technology

Is this electrolysis?

No. Artificial photosynthesis does use water as a feed stock. However, it uses a two-electron pathway to split water into hydrogen and hydrogen peroxide using manmade light or natural sunlight as the energy source.

Electrolysis is a four-electron process that splits water into hydrogen and oxygen by blasting apart the entire water molecule with an electrical current. Electrolysis requires substantially more energy per kilogram to produce hydrogen.

Is this photoelectrochemical (PEC)?

No. Photoelectrochemical (PEC) is electrolysis on a nano-scale. While powered by sunlight, PEC converts sunlight into electricity and uses that to split the water into hydrogen and oxygen just like electrolysis. It is simply electrolysis at a nano-scale in which tiny photovoltaic "chips" convert sunlight into electricity, with all the inefficiencies that photovoltaic solar cells have. Thus, PEC depends on the same four-electron pathway as electrolysis, which reduces water to hydrogen and oxygen. With PEC these gasses are intermingled and must be separated, which drives up energy consumption and cost.

Artificial photosynthesis uses manmade or natural sunlight to split water into hydrogen and hydrogen peroxide that self-separate because one is a gas and the other is a liquid. Furthermore, because light is used directly, there are no energy inefficiencies to overcome as with PEC or solar-powered electrolysis. Thus, artificial photosynthesis is more energy efficient and the cost of the energy, when using direct sunlight, is less than solar, wind, or even grid electricity.

Is the catalyst an enzyme?

No. Our primary catalyst is inorganic and does not require special conditions like an anaerobic environment. Unlike enzymes, our catalysts are not consumed in the reaction and can be used repeatedly … perhaps indefinitely.

How pure is the hydrogen produced by artificial photosynthesis?

We are working to ascertain this information, but one factor will be the purity of the water being split. Filtered, ionized water will be quite different from unfiltered fresh or salt water.

Does artificial photosynthesis work with salt water? Pond water? Tap water?

Our catalyst works best with pure, deionized water. However, it also works with nearly any fresh or salt water source with 80-90% as much efficiency. City water that contains even small amounts of chlorine is not conducive to use with our catalysts. We are continuing to explore different water sources and their impact on the purity of hydrogen produced by each.

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