Extended Data Fig. 4: Mass spectrometer time trace with and without ammonia production.
From: Operando probing of the surface chemistry during the Haber–Bosch process
a, The equivalent experiment as for the data shown in Fig. 1b but at 523 K over Fe(110) with the complete set of mass fragments shown before any data processing, as well as the ammonia signal with all of the data processing. b, The equivalent experiment but at 673 K over Fe(110). Note here that the timescale is far longer than in Fig. 1b to ensure sufficient statistics, ensuring that the relative reactivity is representative of the lack of ammonia production. Note that, in a, there is a glitch in the mass spectrometer background as a response to the removal of N2, but it is clear that mass 15 is decreasing in pure H2 after the switchover. c, The equivalent experiment as b but performed without any X-rays on the sample.
