The　NO　oxidation　on　Cu　2　O(111)　with　molecular　oxygen,　dissociated　oxygen,　and　lattice　O,　was　studied　by　using　periodic　density　functional　theory.　Cu　2　O　could　promote　NO　oxidation　via　the　more　favorable　Elay-Rideal　mechanism.　For　NO　oxidation　with　molecular　oxygen,　path　II　(NO　+　O　2　∗　→　O　∗　ONO　→　NO　2　+　O　∗　;　NO　+　O　∗　→　NO　2　∗　→　NO　2　)　was　found　as　the　most　probable　route,　in　which　NO　2　desorption　is　the　reaction　rate　determining　step.　The　NO　oxidation　reaction　with　dissociated　oxygen　is　also　possible.　In　this　case,　O　2　dissociation　occurs　after　surpassing　a　barrier　of　105　kJ/mol.　Thereafter,　NO　molecule　can　readily　react　with　oxygen　adatoms　without　barrier　or　with　a　moderate-low　barrier　of　49　kJ/mol.　Both　of　the　produced　NO　2　molecules　will　release　from　the　surface.　The　barrier　to　be　surmounted　is　53.3　and　103.2　kJ/mol,　respectively.　The　reaction　of　NO　with　lattice　O　has　a　high　barrier　and　it　is　very　unlikely.　The　present　results　enrich　our　understanding　of　the　catalytic　oxidation　of　NO　by　metal-oxide　catalysts.　©　2014　Elsevier　B.V.　All　rights　reserved.