A team of scientist in England have proposed a new idea that involves getting hydrogen from ammonia to power fuel cell cars that could cut costs and make hydrogen fuel cells much more viable, reports The Engineer:
The science behind their idea is old, having first been discovered by British chemist Arthur Titherley in 1894. His process reacts ammonia with sodium to produce sodium amide, which then breaks down into nitrogen, hydrogen and the original sodium. Ammonia is one of the world’s most widely produced inorganic chemicals and is typically stored in tanks pressurized to about 300 psi. That’s about the same pressure used to store and transport propane, one of the most widely-used fuels in the world.
By contrast, compressed hydrogen must be stored at pressures up to 10,000 psi. That means the tanks to store it in have to be extremely heavy. While ammonia weighs four times as much as hydrogen, an onboard ammonia storage system will still weigh less than one designed for storing hydrogen.
At present, making hydrogen from ammonia relies on ruthenium as a catalyst. Ruthenium is a precious and expensive metal, and the process to separate the hydrogen requires extreme temperatures. But using the sodium-based process proposed by British scientists Martin Owen Jones and Bill David, the process would require temperatures of only 400 degrees Celsius; a typical car battery could supply enough energy to heat their small (1.5 cubic inch) sodium/ammonia reactor to that temperature. The output of their device is not enough to power a large commercial operation, but could be scaled up to supply hydrogen to a fuel cell for cars.
Toyota, Honda, and Hyundai are all working hard on bringing fuel cell cars to market. While a hydrogen fuel cell emits no toxic gasses, most commercially available hydrogen today comes from natural gas which is derived from fracking. When you calculate the total environmental impact of hydrogen, the result is a fairly dismal picture. The process that Jones and David propose offers the possibility of supplying hydrogen for fuel cell cars in a far more earth friendly fashion. It also has the advantage of using storage tanks that are similar to those in common use today, making the build out of infrastructure to support hydrogen powered cars much cheaper and a lot less scary.
Will the Jones/David system be the savior for fuel cell powered cars? We don’t know. All we really do know is that the search for zero-emissions cars is driving a great deal of new research into both hydrogen power and battery chemistry. Which of those ideas will prove commercially feasible and rule the marketplace in the future? If we knew the answer to that, we could make a fortune in the stock market over the next 10 years or so.