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

The hydrogenation of bicarbonate, a byproduct of CO captured in alkaline solutions, into formic acid (FA) using glycerol (GLY) as a hydrogen source offers a promising carbon-negative strategy for reducing CO 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.