Based on the Hirshfeld atomic charge analysis we check the electronic structures of H + or H atom bound to the crystal layers. Due to the high ionization potential of hydrogen, H + picks up an electron (~0.9 e -both in h-BN and MoS 2 ) and is bound to the crystal lattice. This charge is transferred mainly from the atoms that are in closest vicinity. Thus, the proton itself is almost neutralized, while the N or S atoms, to which the proton binds, become positively charged. Also, the second neighbors become slightly more positive, but the effect is much weaker than for the binding atom. This effect is also shown by the electron density isosurfaces (see Figure in SI).