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

Metal–organic framework (MOF)-derived catalysts are widely used for CO2 electroreduction to formate. However, the effect of the local coordination environment of MOF precursors on CO2 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 H2O, while Pb-MOF-e has seven O sites of BTC ligands and two O sites from H2O. 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 CO2·– 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 CO2 electroreduction applications.