Molybdenum　(Mo)　serves　as　the　key　site　in　the　nitrogenase　enzyme,　catalyzing　the　conversion　of　N-2　into　NH3　under　ambient　conditions.　However,　the　strong　affinity　of　Mo　sites　for　N-2　hinders　H-2　adsorption　due　to　the　competitive　nature　of　N-2　and　H-2　on　a　single　site,　resulting　in　an　unsatisfactory　ammonia　synthesis　performance.　Here,　we　propose　an　approach　of　intervening　C-60　layer　as　a　second　site　for　H-2　adsorption　on　two-dimensional　Mo2CTx.　The　C-60　layer　thickness　is　readily　tunable　by　varying　its　loading　content.　An　optimal　C-60　layer　significantly　enhances　the　electronic　interaction　between　the　C-60　layer　and　the　Mo2CTx　layer,　leading　to　a　remarkable　decrease　in　the　work　function　and　an　increase　in　the　electron　density　of　Mo　atoms.　Therefore,　the　separate　adsorption　of　N-2　and　H-2　on　distinct　sites　is　substantially　facilitated.　The　present　work　offers　insights　into　the　correlation　between　structure　and　performance　in　NH3　synthesis　catalysts.