Hydrogen adsorption on TaSe2 monolayer doped with light metals: A DFT study

The first-principle DFT calculation was applied to study hydrogen adsorption performances of pure TaSe2 and that doped with light metals (Li, Na and K). Li, Na or K could successfully substitute one Se atom to build the stable doped TaSe2 with binding energy of -2.614, -3.303 or -4.172 eV, respectively, higher than their cohesive energy. The H-2 interacted weakly with pure TaSe2 but was strongly adsorbed on the doped TaSe2 due to the remarkably improved transferred charges in the doped adsorption systems. The adsorption energy of H-2 on Li was calculated to be -0.289 eV, 179.84% and 361.92% higher than that on Na or K, respectively. Then there were four H-2 molecules stably adsorbed on the Li-doped TaSe2 monolayer with reasonable average adsorption energy and transferred charges of -0.221 eV and 0.77 e, respectively. Further molecular dynamics simulations showed that four H-2 molecules could still be adsorbed on the Li-doped TaSe2 with slightly lower average adsorption energy of -0.189 eV at 300 K. Our study reveals the TaSe2 doped with Li is a promising adsorbent to interact strongly with H-2 along with effective modulation of its conductivity and could be used in the area of hydrogen adsorption/sensing.