Figure: Reaction of ammonia to form dinitrogen presents the possibility of accessing the stored hydrogen equivalents for energy applications.

Could ammonia be developed as a hydrogen storage medium to support a hydrogen-based energy economy? 

The motivationThe ability to efficiently transform molecular dinitrogen into value-added commodity chemicals represents a significant challenge. One lead strategy involves the use of metal-containing compounds to break the N-N triple bond. In many cases, the products of these reactions are unreactive compounds containing a metal-nitrogen multiple bond.

The discovery – SFU researchers discovered that oxidation of certain metal-nitrogen compounds, synthesized from ammonia as the nitrogen source, can be easily activated at room temperature to liberate dinitrogen (N2). They also showed that they can turn off the activation reaction via subtle changes to the compound structure. The authors are currently exploring other mild methods of activating compounds containing metal-nitrogen multiple bonds.

Its significance – This research highlights the tunability of nitrogen activation reactions under mild conditions. Specifically, it is the first example of direct activation of a metal-nitrogen multiple bond via removal of an electron at room temperature. SFU researchers use ammonia (NH3) as the nitrogen source; thus, this chemistry may represent a key step toward the eventual use of NH3 as a hydrogen storage medium. While the controlled release of H2 remains a formidable challenge, NH3 is relatively inexpensive and transportable, and could play an important role in the transition to a hydrogen-based energy economy.

Read the paper“Tuning Electronic Structure to Control Manganese Nitride Activation” by Ryan M. Clarke and Tim Storr. J. Am. Chem. Soc., 138 (47):15299–15302 (2016). DOI: 10.1021/jacs.6b09576

Website article compiled by Jacqueline Watson with Theresa Kitos