19 November 2017
Splitting water using new carbon electrocatalysts
Published online 24 January 2017
New carbon membranes with unique porous structures are promising.
A multidisciplinary team of scientists has synthesized cheap high performance freestanding carbon membranes that can be easily scaled up and potentially used in energy conversion and storage.
Porous carbon materials have been widely studied as electrocatalysts in electrochemical energy conversion and storage, particularly in powder form.
But the shortcomings of these carbon powders are many.
For these powders to be of any applied significance, they have to be mixed and pressed with electronically insulating polymer binders to give them useful defined shapes. This process however weakens the cell's overall electrical conductivity, compromising on efficiency.
Now, researchers from Saudi Arabia and Germany have developed binder-free porous carbon membranes to replace powders.
The newly synthesized membranes have a pore size gradient along the membrane’s cross-section, a structural feature that differentiates these membranes from previously proposed ones, the researchers say.
The membranes were successfully used as electrocatalysts in water splitting, which produces hydrogen from water using special semiconductors.
The scientists say they can also be used in a number of electrochemical devices, such as lithium–air batteries, fuel cells and in electrodialysis, which transports salt ions through solutions for seawater desalination purposes.
The team however says that the true significance of their research lies beyond application.
"We believe that this work significantly advances the current knowledge and technology based on porous carbon materials,” says Hong Wang of the physical science and engineering division at King Abdullah University of Science & Technology (KAUST) in Saudi Arabia, and lead author of this study. “It will promote the research paradigm transition from powders to carbon membranes.”
- Wang, H. et al. Synthesis of single-crystal-like nanoporous carbon membranes and their application in overall water splitting. Nat. Commun. http://dx.doi.org/10.1038/ncomms13592 (2017).