Extended Data Figure 8: Detailed analysis of HRTEM images of the debris layer of MoN_x–Cu.

a, HRTEM image showing nanocrystals of δ′-MoN and γ-Mo₂N embedded in an amorphous carbon matrix. There were also onion-like carbons in many of the regions examined. The d-orbital spacing of 0.341 nm is a typical value for this form of carbon structure^28,29. b, HRTEM image showing the amorphous matrix with one crystalline domain (yellow box), which corresponds to δ-MoN.