Fig. 2: Nitride formation and depletion.
From: Operando probing of the surface chemistry during the Haber–Bosch process
The formation and depletion of nitride on the surface of each catalyst are shown as a function of time. At the top, the N2 gas is introduced with a total pressure of 150 mbar and spectral collection begins. Then, after the nitride begins to stabilize, H2 gas is introduced immediately in a 1:1 ratio with N2 with a total pressure of 300 mbar, reducing the surface within the frame of the detector. Next to each time series are example spectra normalized to the background, with a grey arrow showing the frame it represents. a, The data for 673 K over Fe(110). b, The data for 673 K over Fe(210). c, The data for 623 K over \({\rm{Ru}}(10\bar{1}3)\). For Ru, the spectra shown are the summation of the entire time series. Note the difference in y-axis scale in the spectral figures.
