Charged Boron Nitride Binds CO₂

Industrial processes for CO₂ capture use aqueous amine solutions or ammonia. But both of those methods are energy intensive and plagued with technical challenges including equipment corrosion. In search of alternatives, Aijun Du of Queensland University of Technology, in Australia, and coworkers examined the affinity of CO₂ for BN nanosheets and nanotubes using density functional theory calculations. They found that injecting electrons into the BN materials causes CO₂ to bind tightly and selectively. When the group removed the charge, CO₂ was spontaneously released (J. Am. Chem. Soc. 2013, DOI: 10.1021/ja400243r). The injected electrons populate p-like orbitals located on the boron atoms, imparting a Lewis base character that attracts CO₂, a Lewis acid. The switchable materials could be made into capacitors and used on smokestacks as reusable CO₂-scrubbing cartridges, the team says, or used to separate mixtures produced in natural gas processing or biomass gasification.