Carbon-supported　ruthenium　catalysts　are　very　promising　application　in　ammonia　synthesis.　Here　we　show　that　the　oxygen　functional　groups　can　be　introduced　into　carbon　preloaded　with　Ru　species　by　HNO3　gas-phase　oxidation　treatment.　The　results　reveal　that　the　presence　of　oxygen　functional　groups　facilitates　the　desorption　of　hydrogen　species.　Moreover,　the　decomposition　of　barium　nitrate　is　accelerated,　and　the　ill　effects　of　carbon　methanation　and　hydrogen　poisoning　are　effectively　alleviated.　The　combination　of　the　change　in　the　existing　form　of　Ba　promoter,　the　acceleration　in　the　desorption　and　exchange　of　hydrogen　species　accounts　for　the　superior　ammonia　synthesis　activity　of　Ru　catalyst　with　HNO3　gas-phase　treatment.　Understanding　the　role　of　oxygen　functional　groups　provides　design　rules　for　the　rational　design　of　carbon-supported　Ru　catalyst　with　highly　activity　and　stability　for　ammonia　synthesis　or　other　hydrogen-involved　reactions.　(C)　2022　Elsevier　Inc.　All　rights　reserved.