A Mixed‐Ligand Metal–Organic Framework Strategy to Construct High‐Density O/S‐Shelled Ag Nanoparticle Electrocatalysts for Syngas Modulation

ABSTRACT

Surface ligands can reshape the near‐site microenvironment for CO ₂ electroreduction; however, it remains difficult to install and retain high‐density ligand layers with well‐defined composition under cathodic reconstruction. Here, we introduce a mixed‐ligand metal–organic framework strategy that prearranges lattice‐matched ligands at tunable ratios and translates this composition control into the working catalysts. An Ag–triazole mixed‐linker precursor, MAF‐stu‐11(O/S), is constructed from two ditopic triazole ligands that differ only by ether versus thioether bridges, enabling defined S:O feed ratios while preserving an isoreticular framework. During electrolysis, the crystalline precursors reconstruct into ligand‐shelled Ag nanoparticle catalysts while retaining detectable O/S‐rich interfacial species derived from the parent scaffold. This enables systematic tuning of syngas selectivity through the combined effects of O/S ligand ratio and applied potential, with H ₂ /CO continuously adjustable from about 0.14 to 2.86 while sustaining practical current densities. Electrochemical analyses and in situ ATR‐FTIR tracking of both intermediates and ligand evolution support a ligand‐mediated regulation of interfacial proton/water accessibility and CO ₂ activation. More broadly, this work provides a potentially general route to access composition‐defined, high‐density ligand‐shelled metal nanoparticle electrocatalysts via metal–organic framework rational design and electrochemical reconstruction.