NCSU researchers develop catalytic compound to produce hydrogen and syngas feedstock

Researchers from the North Carolina State University (NCSU), US, have developed a new catalytic compound that uses solar power to convert methane and water into hydrogen and syngas.

Compared to previous thermal water-splitting methods, the new catalytic material is more than three times more efficient at converting water into hydrogen gas, researchers claim.

NCSU PhD student in the lab of professor Fanxing Li and lead author of two articles describing the material and process, Feng He said: "We're excited about the new material and process because it converts water, inexpensive natural gas, and clean, renewable solar energy into valuable syngas and hydrogen fuels."

The cleanest way to produce hydrogen gas is to split water into hydrogen and oxygen, but researchers have struggled to develop a cost-effective, water-splitting technique.

Syngas, a combination of carbon monoxide and hydrogen, is used as a feedstock for commercial processes that produce synthetic diesel fuels, olefins and methanol.

This technique hinges on a new catalytic material that is a composite of iron oxide and lanthanum strontium iron oxide, also called LSF.

Iron oxide can be used as a catalyst for thermal water splitting, but it is not very efficient and the addition of LSF improves the iron oxide's activity, making it far more efficient.

By using the new compound, researchers were able to convert 77% of the water they used in the form of steam into hydrogen. The previous conversion mark for thermal water-splitting was around 20%.

Feng He added: "We're optimistic that commercial utilisation of this technique could promote the efficient usage of solar energy and domestic natural gas, produce relatively low carbon dioxide emissions while making liquid transportation fuel, and generate low-cost, high-purity hydrogen."

With the new technique, methane is injected into a reactor that is heated with solar energy and the chamber that contains the catalytic composite, which reacts with the methane to produce syngas and carbon dioxide.

This process reduces the composite particles, stripping them of oxygen. Syngas is removed from the system and the reduced composite particles are diverted into a second reactor.

Following this, high-temperature steam is pumped into the second reactor, where it reacts with the reduced composite particles to produce hydrogen gas that is at least 97% pure.

This process reportedly also reoxygenates the composite particles, which can then be reused with the methane, starting the cycle all over again.

The steam has to be primarily produced with an external energy source, but once the cycle is started the chemical reactions produce sufficient heat to convert water into steam without an external heat source.