Room temperature synthesized layered CAU-17 MOFs for highly active and selective electrocatalytic CO2 reduction to formate

Modulating the morphology of metal-organic frameworks (MOFs) has been identified as an effective strategy for enhancing the electrocatalytic performance of CO 2 reduction reactions (CO 2 RR). In this study, CAU-17 MOFs ([Bi(BTC)(H 2 O)]·2 H 2 O·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-17-Layer). Compared to CAU-17-HP, CAU-17-Layer exhibits an excellent selectivity towards formate with the maximum Faradaic efficiency of 95.5% at − 1.1 V RHE in an H-cell. Subsequently, the limited catalytic activity of CAU-17-Layer was boosted by anchoring nano CeO 2 onto its surfaces (CeO 2 @CAU-17-Layer). The as-prepared composite catalyst demonstrated outstanding performance in the conversion of CO 2 to formate, with a current density surpassing − 100 mA cm -2 at potentials more negative than − 1.0 V RHE and reaching − 200 mA cm -2 at − 1.5 V RHE in a flow cell. This study demonstrates the significant potential of morphology-engineered and rare-earth metals composited MOFs in facilitating highly efficient reduction of CO 2 .