The　electrocatalytic　coupling　of　methanol　and　CO　to　produce　dimethyl　carbonate　(DMC)　is　an　attractive　strategy　for　converting　C1　resources　into　value-added　products,　while　the　controlled　adsorption　and　coupling　of　two　key　intermediates,　*CO　and　*OCH3,　have　not　been　demonstrated　yet.　Herein,　a　heterointerface　engineering　strategy　is　developed　to　modulate　intermediate　adsorption　and　facilitate　the　C─O　bond　formation.　By　constructing　a　Pd　and　PdO　heterostructure　catalyst　with　abundant　interfaces　(designated　as　Pd/PdO-r),　the　Pd0　sites　serve　to　stabilize　*CO　and　the　electrophilic　Pd2+　sites　can　promote　the　*OCH3　adsorption,　thereby　optimizing　their　spatial　proximity　and　reactivity.　In　addition,　the　heterointerfaces　allow　to　lower　the　coupling　reaction　barrier,　enabling　an　efficient　electrocatalytic　pathway　for　the　DMC　synthesis.　Consequently,　the　Pd/PdO-r　heterostructure　catalyst　exhibited　a　high　Faradaic　efficiency　of　86%　with　a　DMC　yield　rate　of　252 µmol　h−1　mgcat−1　in　flow　cells.　The　work　suggests　an　effective　approach　to　design　heterointerfaces　for　enhanced　intermediate　adsorption　and　coupling,　thus　promoting　the　formation　of　valuable　multicarbon　products　from　C1　resources.　©　2025　Wiley-VCH　GmbH.