The　addition　of　Ce　species　in　La2O3　can　enhance　the　number　of　defect　sites　and　generate　the　Ce1-xLaxO2-3　solid　solution,　thereby　increasing　the　amount　of　the　exposed　ruthenium　species　and　proportion　of　metallic　ruthenium　species.　The　presence　of　Ce　species　in　Ru/　La2O3　promotes　the　desorption　of　hydrogen,　and　hydrogen　species　prefers　to　desorb　in　the　H-2　molecule　formation　pathway.　On　the　other　hand,　the　difference　in　the　Ce　addition　method　strongly　affects　the　exchange　between　the　adsorbed　hydrogen　species　on　Ru　catalyst　with　the　gaseous　hydrogen　species.　Owing　to　improvement　of　the　proportion　of　oxygen　vacancy,　Ru-0　and　number　of　the　exposure　of　ruthenium　species,　H-2　species　adsorbed　on　Ru/LaCe-C　prepared　by　coprecipitation　method　preferentially　desorbs　in　the　formation　of　H-2　pathway,　and　a　large　proportion　of　the　adsorbed　H　species　would　exchange　with　the　hydrogen　species　from　the　gaseous　phase,　which　leads　to　improvement　of　ammonia　synthesis　rate　by　75%　in　comparison　with　Ru/La2O3　catalyst.　(C)　2022　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.