Next generation water splitter could help renewables power the globe
https://www.sciencemag.org/news/2020/03/next-generation-water-splitter-could-help-renewables-power-globe
Source: By Robert F. Service, Science Magazine.
Excerpt: Running the world on renewable energy is simple, in principle: Harvest solar and wind energy, and use any extra to power devices called electrolyzers that split water into oxygen (O2) and hydrogen gas. Hydrogen (H2) can serve as a fuel; it is also a staple of the chemical industry. The trouble is that current electrolyzers are costly, requiring either expensive catalysts or pricey metal housings. ... To make the water able to better conduct ions that move through the devices, today’s most common electrolyzers add high levels of potassium hydroxide (KOH) to the water. ... But KOH is highly caustic, so engineers have to build their devices out of expensive inert metals such as titanium.... That drawback prompted researchers in the 1960s to develop a version of the technology known as a proton-exchange membrane (PEM) electrolyzer, in which the dividing membrane is designed to selectively allow H+ ions through. ... They also require catalysts made from platinum and iridium...expensive and rare. ...Now, researchers report combining the best of both approaches to make a version that needs only cheap materials. ... The new device generates hydrogen about three times faster than conventional alkaline devices, though still more slowly than commercial PEM electrolyzers, Kim and his colleagues report. ...Initial indications suggest the membrane begins to break down after only about 10 hours of operation. ...The team hopes that adding fluorine to the membrane will repel the water. With that and other fixes, Kim hopes, AEM electrolyzers could join solar cells and windmills as a key technology for a carbon-free world....
Source: By Robert F. Service, Science Magazine.
Excerpt: Running the world on renewable energy is simple, in principle: Harvest solar and wind energy, and use any extra to power devices called electrolyzers that split water into oxygen (O2) and hydrogen gas. Hydrogen (H2) can serve as a fuel; it is also a staple of the chemical industry. The trouble is that current electrolyzers are costly, requiring either expensive catalysts or pricey metal housings. ... To make the water able to better conduct ions that move through the devices, today’s most common electrolyzers add high levels of potassium hydroxide (KOH) to the water. ... But KOH is highly caustic, so engineers have to build their devices out of expensive inert metals such as titanium.... That drawback prompted researchers in the 1960s to develop a version of the technology known as a proton-exchange membrane (PEM) electrolyzer, in which the dividing membrane is designed to selectively allow H+ ions through. ... They also require catalysts made from platinum and iridium...expensive and rare. ...Now, researchers report combining the best of both approaches to make a version that needs only cheap materials. ... The new device generates hydrogen about three times faster than conventional alkaline devices, though still more slowly than commercial PEM electrolyzers, Kim and his colleagues report. ...Initial indications suggest the membrane begins to break down after only about 10 hours of operation. ...The team hopes that adding fluorine to the membrane will repel the water. With that and other fixes, Kim hopes, AEM electrolyzers could join solar cells and windmills as a key technology for a carbon-free world....