LAUSR

Abstract The adsorption of CO 2 , CO, and O 2 on the (001) surfaces of the CsPbX 3 (X = Cl, Br, and I) perovskites have been investigated at the first-principles level, using a hybrid exchange-correlation functional optimized to yield description of their structural, electronic, and dynamic properties, in good agreement with experiment. The CsX- and PbX 2 -terminated slabs without defects have been considered, and their dynamic properties determined, revealing zone-boundary phonon instabilities for q = π a ( 1 , 0 ) and π a ( 1 , 1 ) . Further on, the relaxation patterns at the surfaces due to adsorption of molecules have been studied for different docking sites, and the corresponding adsorption energies estimated. On the CsX-terminated surfaces, CO 2 was found to be more reactive than CO or O 2 . On the PbX 2 -terminated surfaces, the CO 2 reactivity is two times weaker than on the CsX-terminated ones, becoming in fact comparable to that of CO and O 2 , the latter having the lowest adsorption energy. The adsorption does not seem to have any significant impact on the electronic structure of the surfaces, whatever the perovskites, types of surfaces or molecules. The obtained adsorption energies and electronic structures permit to characterize attachment of the molecules studied on the surfaces in question as physisorption.