Adsorption of water molecule on (001) and (110) surfaces of MgH2

► H2O prefers to adsorb on (110) surface with an adsorption energy of − 0.96 eV. ► Surface structure was distorted by the adsorption of H2O. ► Bonding interactions between O and Mg atoms affect adsorption of water molecule. ► It could potentially generate Mg(OH)2 if H2O dissociates on surfaces of MgH2.