Electrochemical reduction of CO₂ holds promise for renewable energy storage and electrolytic fuel generation. Previous studies have surveyed multiple aspects for engineering selective and efficient catalysts (such as size scale¹, composite material² and electrolyte co-catalysis³, etc.). Along with the density functional theory based simulation, the selectivity descriptors for the most common products CO and HCOOH are *COOH and *HCOO, respectively.⁴ The fact that CO reduction yields similar hydrocarbon products distribution suggests that CO is the ideal intermediate for further hydrogenated products.⁵ So far, only Cu-based catalysts yield energy-dense liquid hydrocarbon products⁶ (ie. CH₃OH and C₂H₅OH, etc.), this can be attributed to the unique binding energies of CO* and COH*.⁷

Inspired by enzyme chemistry that leverage metal nanoclusters with ligands in photosynthesis⁸, we explored the possibility using engineered metal-ligand electrocatalyst to yield the hydrocarbon liquid products. Our previous study on thiolate-Au system has proved ligands facilitate the proton coupled electron transfer (PCET) with mild acidic pKa.⁹ In the present work, we considered functional ligands supported by silica facilitates the PCET in CO₂ reduction on Pd nanoparticle tripled that yield of the CH₃OH production. Ligand facilitated PCET with metal center that favor CO production and adsorption may be a promising strategy for selective electrochemical CO₂ reduction.

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