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Rare metals could make hydrogen-powered cars more efficient

Rare metals could make hydrogen-powered cars more efficient
From Engadget - November 20, 2017

The system builds on a hydrogen production process called steam reforming. During the process used today, 700 to 1,000 degree Celcius steam reacts with methane (natural gas) under high pressure in the presence of a catalyst like nickel or platinum, producing H2, water and CO2. The problem is that only 65-75 percent of the methane's energy is captured as hydrogen and the process still releases significant amounts of CO2 -- about half of what your car produces when burning gasoline.

By adding a ceramic membrane to that process, the researchers were able togenerate hydrogen from natural gas in one step "with near zero energy loss," they said. The membrane is made from barium, zirconia, yttrium and other rare elements, and the trick is to apply an electrical voltage difference across its surface. When you do that, the steam and methane mix will transit to the other side as protons, creating ionized hydrogen.

The end result is concentrated, impurity-free hydrogen that's already compressed electrochemically at up to 50 bar (750 psi). With not much more treatment, it's then ready to be used in a fuel-cell vehicle or for industrial purposes. The team did not mention how pollutive the process would be, but if less methane is required to make the same amount of hydrogen, it should produce less CO2. The system retains about 88 percent of the methane's energy, so "zero energy loss" is actually about a 12 percent loss.

They also note that the process scales down well, meaning you could produce hydrogen from your own natural gas lines using a small generator. That would let you refuel a hydrogen car at home, much as you can with an EV, reducing the need for complex H2 fueling infrastructure.

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