Facile dissociation of molecular nitrogen using lanthanide surfaces: Towards ambient temperature ammonia synthesis
Jay R. Chan, Stephanie Lambie, Joe Trodahl, D. Lefebvre, Maxime Le Ster, Ali Shaib, Felicia Ullstad, S. A. Brown, B. J. Ruck, Anna L. Garden, F. Natali
Abstract
A combined experimental and computational study is reported on a hitherto unrecognised single lanthanide catalyst for the breaking of molecular nitrogen and formation of ammonia at ambient temperature and low pressure. We combine in situ electrical conductance and electron diffraction measurements to track the conversion from the lanthanide metals to the insulating lanthanide nitrides. The efficiency of the conversion is then interpreted using $\mathrm{DFT}+U$ calculations, suggesting a molecular nitrogen dissociation pathway separate from that well established for transition metals. Finally, we show that exposure of the lanthanide surfaces to both molecular nitrogen and hydrogen results in the formation of ammonia.