Modulating the MOF Coordination Environment to Derive Nanoparticles for CO₂ Electroreduction to Formate

Metal–organic framework (MOF)-derived catalysts are widely used for CO 2 electroreduction to formate. However, the effect of the local coordination environment of MOF precursors on CO 2 electroreduction activity is still unclear. Herein, Pb-MOF precursors with different coordination environments were synthesized by electrodeposition (Pb-MOF-e) and hydrothermal (Pb-MOF-t) methods, respectively. The coordination environment in Pb-MOF-t has eight O sites of benzene-1,3,5-tricarboxylate (BTC) ligands and one O site from H 2 O, while Pb-MOF-e has seven O sites of BTC ligands and two O sites from H 2 O. Pb-MOF-e and Pb-MOF-t could be derived into 4 and 70 nm particles on Pb and carbon paper (CP), and the catalysts are named Pb NP-e/Pb, Pb NP-e/CP, and Pb NP-t/CP. In particular, Pb NP-e/Pb exhibited higher formate selectivity (92.0%), with a maximum formate formation rate of 2734.5 μmol cm –1 h –1 at −2.4 V (vs Ag/Ag + ), which is 4.7 and 5.8 times higher than that Pb NP-e/CP and Pb NP-t/CP. The experimental results showed that Pb-MOF-e has evolved structurally to form Pb nanoparticles with large an electrochemically active surface area, low interfacial transport resistance, and low adsorption potential of CO 2 ·– intermediates. In addition, the edge of Pb nanoparticles as the active site could efficiently stabilize the *OCHO intermediate and enhance the activity. The obtained Pb NP-e/Pb catalyst shows promising prospects in CO 2 electroreduction applications.