Modulating　the　morphology　of　metal-organic　frameworks　(MOFs)　has　been　identified　as　an　effective　strategy　for　enhancing　the　electrocatalytic　performance　of　CO2　reduction　reactions　(CO2RR).　In　this　study,　CAU-17　MOFs　([Bi　(BTC)(H2O)]&　sdot;2　H2O　&　sdot;MeOH)　were　prepared　via　a　sonication-assisted　method　at　room　temperature,　which　is　considered　a　simpler　technique　compared　to　the　conventional　hydrothermal　method.　Additionally,　the　morphology　of　CAU-17　MOFs　was　further　regulated　by　incorporating　a　rare-earth　metal　(La),　resulting　in　the　observation　of　two　distinct　structures,　i.e.　CAU-17　hexagonal　prism　(CAU-17-HP)　and　CAU-17　layer　(CAU-17Layer).　Compared　to　CAU-17-HP,　CAU-17-Layer　exhibits　an　excellent　selectivity　towards　formate　with　the　maximum　Faradaic　efficiency　of　95.5%　at1.1　VRHE　in　an　H-cell.　Subsequently,　the　limited　catalytic　activity　of　CAU-17-Layer　was　boosted　by　anchoring　nano　CeO2　onto　its　surfaces　(CeO2　@CAU-17-Layer).　The　as-prepared　composite　catalyst　demonstrated　outstanding　performance　in　the　conversion　of　CO2　to　formate,　with　a　current　density　surpassing　-　100　mA　cm　-2　at　potentials　more　negative　than　-　1.0　VRHE　and　reaching　-　200　mA　cm　-2　at1.5　VRHE　in　a　flow　cell.　This　study　demonstrates　the　significant　potential　of　morphology-engineered　and　rareearth　metals　composited　MOFs　in　facilitating　highly　efficient　reduction　of　CO2.