The　Co@BN　core–shell　nanostructure　of　Co　core　and　boron　nitride　(BN)　shell　was　prepared　through　a　facile　one-step　thermal　treatment.　The　as-prepared　Co@BN　nanocomposites　exhibited　excellent　dye-sensitized　photocatalytic　hydrogen　evolution　activity　(13.78　mmol　h−1　g−1)　with　visible　light　and　the　apparent　quantum　yield　was　1.15%.　The　enhanced　adsorption　of　EY　on　the　BN　shell　and　the　Co/BN　Schottky　junction　facilitate　the　tandem　transfer　of　photo-generated　carriers　to　the　Co　surface.　Moreover,　the　core–shell　interface　serves　as　a　nanoreactor　boosting　the　reduction　of　H+　to　H2　on　the　Co　surface.　Additionally,　the　magnetic　recyclability　makes　Co@BN　favorable　for　its　practical　application.　This　work　extends　the　application　of　the　＇photocatalysis　under　shell＇　and　has　potential　in　dye-sensitized　solar　cell.　©　2020　Elsevier　B.V.