Heterogeneous catalytic and chemical looping routes to N2 activation: general discussion

Justin S. J. Hargreavesopened discussion of the introductory lecture by HideoHosono: In the case of conventionally supported ruthenium catalysed ammoniasynthesis there is a strong inuence of particle size which can be associated withthe expression of B5 active sites. In the case of electride supported ruthenium isthe nature of any structure sensitivity different?Hideo Hosonoresponded: Ru B5 sites exhibit high activity. I think this is alsotrue for the electride support. The role of the electride is promotion of electrons tothe N2absorbed on the Ru, leading to N2dissociation.One thing to add: LaRuSi is a layered crystal. Ru atoms form a planar unit, withno B5 site, but this material works well. The turnover frequency (TOF) is 600 timeshigher than that of pure Ru powder. Density functional theory (DFT) calculationsrevealed that the dissociation of N2occurs easily on the exposed Ru plane ofLaRuSi. A systematic study providesrm evidence that layered Ru with a negativecharge in LnRuSi is a new type of active site that differs signicantly from B5sites.1I think the active site is not restricted to B5 sites.