Fig. 2. (a) XRD patterns of Ti₃C₂T_x, Ti₃C₂T_x/ZIF-67, and Ti₃C₂T_x-Co@NCNTs, (b) Raman spectrum of Ti₃C₂T_x, and Ti₃C₂T_x-Co@NCNTs, (c) FT-IR spectrum of Ti₃C₂T_x, Ti₃C₂T_x/ZIF-67 and Ti₃C₂T_x-Co@NCNTs, and high-resolution XPS spectra of (d) Ti 2p, (e) N 1s, (f) Co 2p, and (g) O 1s.