“Energy efficiency is key to the future of hydrogen as a clean fuel” says co-author Irene Yuste, chemical engineer at CoorsTek Membrane Sciences and PhD candidate at the University of Oslo. “Our work shows that protonic membranes can make hydrogen from ammonia, natural gas and biogas so efficiently that hydrogen fuel cell cars will have lower carbon footprint than electric cars charged from the electricity grid.”
Proton ceramic membranes are electrochemical energy converters, like batteries and fuel cells. They work by first splitting hydrogen-containing molecules, such as water or methane, and then further breaking hydrogen atoms into protons and electrons. Protons are transported through the solid ceramic membrane while electrons are transported separately through a metallic conductor connected to a power source. When protons and electrons recombine on the other side of the ceramic membrane, pure hydrogen is produced as a compressed gas.
“When energy is transformed from one form to another there is energy loss”, explains Jose Serra, professor with Instituto de Tecnología Química in Spain, and a co-author of the report in Science. “With our proton ceramic membranes, we can combine otherwise distinct steps of conventional hydrogen production from fuels like natural gas and ammonia into a single stage where heat for catalytic hydrogen production is supplied by the electrochemical gas separation. The result is a thermally balanced process that makes hydrogen with near zero energy loss.”
Proton ceramic membranes have been under development at universities and corporate laboratories for three decades, with thousands of scientists contributing to incremental improvements. The news today is that, for the first time, proton ceramic membrane technology has been demonstrated at practical scales to make hydrogen for fuel cell cars and other clean energy deployments.
Key to the recent breakthrough in the scale-up is a novel material developed by CoorsTek Membrane Sciences from glass-ceramics and metal particles bonding into a composite that can be shaped like a glass during fabrication, has the high-temperature robustness of a ceramic, and the electronic conductivity of a metal.
“Our ceramic membrane technology is built from small cells that are joined into stacks and further combined into bigger modules”, says Per Vestre, Managing Director for CoorsTek Membrane Sciences. “The modular nature of this technology makes it possible to start with small hydrogen generators and scale big by adding new modules as demand for hydrogen increase.”
With the ability to run on natural gas, biogas, or ammonia, the proton ceramic membranes offer a fuel-flexible and fuel-flexible hydrogen production platform. And when hydrocarbons are used as fuel, the membranes directly deliver by-product CO2 as a concentrated stream that can easily be liquified for cost-effective transport to use or storage so that no carbon is released to the atmosphere.