The adsorption of carbon and nitrogen oxides on the PuO 2 {110} surface: A DFT plus U study

The adsorptions of CO, CO 2 , N 2 O, NO and NO 2 on the PuO 2 {110} surface have been studied using density functional theory with a Hubbard U correction. Different approaching pathways are analysed to locate physisorbed states. Starting from the most stable physisorbed structures, reaction paths leading to stable chemisorbed structures are determined. The chemisorptions of CO, CO 2 , N 2 O, NO and NO 2 are extensively studied and the following aspects are compared: molecule/surface structures, atomic magnetic moments, surface work functions, density of states, adsorption energies and reaction barriers. With the exception of N 2 O, chemisorption is energetically favourable on PuO 2 {110}. Dioxide adsorption is more favourable than monoxide, and the chemisorption of nitrogen monoxide/dioxide is easier than carbon monoxide/dioxide. Chemisorption of monoxides reduces a neighbouring surface Pu, thereby providing an active site for interaction with further incoming residual molecules.