Transition-metal cation intercalation in Mo2CTx MXene: Intercalant-dependent structural evolution

Duman N., Cakir D., Abraham B. M., AYDINOL M. K., Gogotsi Y., Buke G. C.

Journal of Alloys and Compounds, vol.1082, 2026 (SCI-Expanded, Scopus)

  • Publication Type: Article / Article
  • Volume: 1082
  • Publication Date: 2026
  • Doi Number: 10.1016/j.jallcom.2026.191101
  • Journal Name: Journal of Alloys and Compounds
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Public Affairs Index, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
  • Keywords: Characterization, Electrocatalysis, Intercalation, Mo2CTx, MXene, Post-process
  • Middle East Technical University Affiliated: Yes

Abstract

Transition-metal cation intercalation provides a practical post-synthetic route for modifying the interlayer structure of MXenes. However, intercalant-dependent structural evolution in Mo2CTx MXene has not been systematically examined under directly comparable processing conditions. Here, Mo2CTx MXene was synthesized by selective etching of Mo2Ga2C and subsequently treated with Cu2+, Ni2+, Co2+, or Mn2+ ions. X-ray diffraction (XRD) reveals intercalant-dependent basal-spacing expansion, with Mn-, Co-, and Ni-intercalated samples showing an interlayer expansion of approximately 2 Å, whereas Cu-intercalated Mo2CTx shows a smaller expansion of approximately 1 Å and less well-resolved higher-order basal reflections. X-ray photoelectron spectroscopy (XPS) shows cation-dependent shifts in the Mo 3d region and distinct chemical-state signatures for Cu, Co, and Ni, consistent with changes in the Mo chemical environment of the MXene host. Complementary characterization supports the incorporation of transition-metal species while showing that the Mo–C framework and stacked morphology are largely retained after intercalation. Alkaline hydrogen evolution measurements and descriptor-level density functional theory (DFT) calculations on idealized Mo2CO2 models are used as functional probes of the intercalation-induced changes. Overall, this study shows that transition-metal cation intercalation produces intercalant-dependent structural evolution in Mo2CTx MXene, linking basal-spacing expansion, chemical-state changes, and electrochemical response under identical processing conditions.