Hydriding and dehydriding energies of PuHx from ab initio calculations

•We obtain the AFM ground state for PuH2 and the FM ground state for PuH3.•We firstly present the chemical potential of hydrogen at 300–1500K.•The equilibrium hydrogen pressure for PuHx is given for the first time.

Based on ab initio   calculations within the density-functional theory (DFT)+U(DFT)+U theoretical formalism, we systematically study the electronic properties of different PuHx compounds. We successfully obtain the antiferromagnetic ground state for PuH2 and the ferromagnetic ground state for PuH3. In combination with chemical potential calculations, we obtain the hydriding and dehydriding energies for PuHx compounds at different temperatures, which accord well with available experimental results. The equilibrium hydrogen pressure along the hydriding and dehydriding processes is presented and carefully analyzed.