Structural, magnetic properties of in-plane chemically ordered (Mo2/3R)2AlC (R = Gd, Tb, Dy, Ho, Er and Y) MAX phase and enhanced capacitance of Mo1.33C MXene derivatives

The crystallographic structure of rare-earth-contained (Mo2/3R1/3)2AlC (R = Gd, Tb, Dy, Ho, Er and Y) i-MAX phases have been verified to be C2/c monoclinic. The magnetic behaviors are varied from antiferromagnetism to non-linear ferromagnetism from R = Gd to Ho in (Mo2/3R1/3)2AlC i-MAX phases due to variant R-R interactions. The capacitance of Mo1.33[email protected]R MXene derived from different (Mo2/3R1/3)2AlC precursors varies from 170 F/g to 228 F/g but can be double by hydrazine monohydrate treatment. The highest one of 431 F/g up to now has been achieved in Mo1.33[email protected] MXene, which is caused by the increased fraction of critical -O group evidenced by XPS spectra. Our results illustrate the promising applications in supercapacitor of Mo1.33C MXene derived from R-contained (Mo, R)2AlC i-MAX phases.