Tuning metal-support interactions in MOF-derived CoNi@NC supported Pd catalysts for efficient hydrogenation of bicarbonate using glycerol as a hydrogen donor

Abstract

The hydrogenation of bicarbonate, a byproduct of CO₂ captured in alkaline solutions, into formic acid (FA) using glycerol (GLY) as a hydrogen source offers a promising carbon-negative strategy for reducing CO₂ emissions. While Pd-based catalysts are effective in this reaction, they often require high temperatures, leading to low FA yield due to strong hydrogen adsorption on Pd surfaces. In this work, metal–organic framework derived N-doped carbon encapsulated CoNi alloy nanoparticles (CoNi@NC) were prepared, acid-leached, and employed as a support to modulate the electronic structure of Pd-based catalysts. The electron transfer driven by the Mott–Schottky effect increases the electron density of Pd, lowers its d-band center, and thereby weakens hydrogen adsorption on Pd. Consequently, Pd/CoNi@NC achieved a full conversion of GLY with 87.2% yield of lactic acid and 57.3% yield of FA, outperforming Pd/NC and Pd/C. Additionally, Pd/CoNi@NC demonstrated high catalytic stability and was magnetically separable for ease of use.