Carbon　encapsulated　iron　catalysts　hold　great　potential　for　one-step　hydroxylation　of　benzene　to　phenol　due　to　their　unique　core-shell　nanostructures.　However,　their　catalytic　performance　is　moderate,　since　the　carbon　shells　have　impeded　their　activity　toward　H(2)O(2)activation.　Herein,　we　demonstrate　that　alloying　engineering　of　Fe　cores　with　Co　atoms　is　a　promising　strategy　to　address　the　issue　about　H(2)O(2)activation.　The　incorporation　of　Co　into　Fe　cores　can　generate　strong　synergetic　effects　to　promote　H(2)O(2)activation,　while　still　maintaining　the　structural　benefits　of　carbon　shells　for　benzene　hydroxylation　reaction.　As　a　result,　the　phenol　yield　obtained　on　carbon　encapsulated　FeCo　(FeCo@C)　reaches　to　26.4　+/-　0.7%　with　a　selectivity　of　96.2　+/-　1.2%,　much　higher　than　that　of　Fe@C　and　Co@C.　With　the　improved　intrinsic　catalytic　behavior　toward　H2O2　activation　and　well　reserved　carbon　structure　benefits,　FeCo@C　should　be　a　promising　catalyst　for　a　broad　liquid-phase　reactions　using　H(2)O(2)as　the　oxidant.