  (2D) lateral heterostructures (LH) combining Ti$_2$C and Ta$_2$C MXenes were
investigated by means of first-principles calculations. Our structural and
elastic properties calculations show that the lateral Ti$_2$C/Ta$_2$C
heterostructure results in a 2D material that is stronger than the original
isolated MXenes and other 2D monolayers such as germanene or MoS$_2$. The
analysis of the evolution of the charge distribution with the size of the LH
shows that, for small systems, it tends to distribute homogeneously between the
two monolayers, whereas for larger systems electrons tend to accumulate in a
region of $\sim$~6 {\AA} around the interface. The work function of the
heterostructure, one crucial parameter in the design of electronic nanodevices,
is found to be lower than that of some conventional 2D LH. Remarkably, all the
heterostructures studied show a very high Curie temperature (between 696 K and
1082 K), high magnetic moments %present in the ferromagnetic ground state, and
high magnetic anisotropy energies. These features make (Ti$_2$C)/(Ta$_2$C)
lateral heterostructures very suitable candidates for spintronic,
photocatalysis, and data storage applications based upon 2D magnetic materials.
