First-principles Study Of Hydrogen Adsorption On The Two-dimensional GaN Nanosheet

The structural,energy and electronic properties of hydrogen molecules adsorbed on alkali metals?Li,Na and K?and transition metals?Ni,Pd and Pt?decorated GaN-ML are systematically investigated based on the first-principles calculations based on density functional theory?DFT-D2 method?.Hydrogen adsorption has a large adsorption energy and a very unstable structure on a pristine GaN-ML.Therefore,the hydrogen storage ability of the pristine GaN-ML can be remarkably improved by introducing alkali and transition metals to decorate GaN-ML.By calculating the binding energy of the metal on the pristine GaN-ML,we choose the most stable decoration position to be the top position of the N atom.The structure and related properties of a hydrogen molecule adsorbed on the metal to decorate the substrate at the top of the N are studied.The result shows that the adsorption of hydrogen on the transition metal-decorate GaN-ML is smaller than that of the alkali metal-decorate GaN-ML,and the structure is more stable.The structure and the electronic properties of multiple hydrogen molecules adsorbed on the Pt-decorate GaN-ML are specifically studied.These current properties of hydrogen molecules adsorbed on alkali metal and transition metal decorated GaN-ML will help guide scientists to develop better hydrogen storage materials in the future.We systematically study the geometric stability and hydrogen storage capacity of Ni atom decorated GaN monolayer?GaN-ML?with three types defects(V_N and V_Gaa substrates,SW defect)using the first-principles calculations based on density functional theory?DFT-D2method?.For Ni-decorated defective GaN-ML,Ni atom can be stably combined on substrates due to higher binding energy,and the Ni atom can accommodate up to three H₂ molecules.The H₂ molecules adsorbed on Ni-decorated V_Gaa substrate undergo a weak physical interaction.However,the Ni-decorated V_N and SW defect substrates show sensitive to H₂ molecules,which can satisfy the requirement for hydrogen storage.Therefore,these results indicate that the Ni-decorated defective GaN-ML can be potential candidates for better storage of H₂molecules.Our work can supply some guidance to explore promising novel hydrogen storage materials using group ?-? nitrides.