Substantial emissions of CO 2 have presented formidable challenges for global climate dynamics. Electrochemical reduction of CO 2 to produce formic acid (HCOOH) is considered to be a promising approach for achieving carbon neutrality. Nevertheless, the development of a catalyst exhibiting both high catalytic activity and selectivity toward desired products remains an arduous task. Herein, we report the synthesis of a unique porous bismuth-based MOF (Bi-BTC) through microwave-assisted agitation. The Bi-BTC MOF has a good catalytic performance in electrochemical CO 2 RR to formate products. At -0.9 V (vs RHE) potential, the Faradaic efficiency of formate can reach 96%, and the current density of the CO 2 RR is 25 mA/cm 2 . Bi-BTC also exhibits good electrochemical stability. FE formate and current density were maintained for 24 h with almost no attenuation. It was found that Bi-BTC was reconstructed in the CO 2 RR process. The shape of nanocolumn before electrolysis is transformed into an ultrathin nanosheet. The soft and hard acid-base theory (HSAB) proves that the reason for the reconfiguration is that the hard base ions (HCO 3 - ) and the intermediate acid (Bi 3+ ) break in the Bi-O bond in Bi-MOF, resulting in the transition of the original column structure of Bi-BTC to Bi 2 O 2 CO 3 ultrathin nanosheeets. The DFT calculation shows that the restructured Bi 2 O 2 CO 3 nanosheet exposes a crystal surface structure, which is conducive to lower the activation energy barrier of the electrochemical CO 2 RR intermediate *OCHO and stabilizing the reaction intermediate. Therefore, it is more beneficial to improve the selectivity of the electrochemical CO 2 RR to formate formation. This result proves that irreversible reconfiguration of catalyst is beneficial to electrochemical CO 2 RR. In addition, coupling a Bi-BTC cathode with a stable anode (IrO 2 ) enables battery-driven high-activity CO 2 RR and an OER with good activity and efficiency.