Microenvironment Regulation of Metal-Organic Frameworks to Anchor Transition Metal Ions for the Electrocatalytic Hydrogen Evolution Reaction

Bearing triazine-centered linkers, three primitive metal-organic frameworks (MOFs) with a Zr6O4 cluster have been prepared as ZrL1 (without any branch), ZrL2 (with -F), and ZrL3 (with -SCH3). The electrocatalytic hydrogen evolution reaction (HER) by their pristine and transition metal-loaded (TM loaded) forms was studied. It was found that the loading of TM ions could enhance the electrocatalytic power of these TM-loaded MOFs in HER, as reflected by their lower overpotentials and smaller Tafel slopes when compared with primitive MOFs. More importantly, the best electrocatalytic HER performance of ZrL3TM among all TM-loaded MOFs studied in this work highlights the effective housing of TM ions for unambiguous active sites through cooperative coordination by triazinic N and thioether pendants. This work proposes microenvironment regulation of MOFs as an effective strategy to enhance the electrocatalytic activity of MOF materials.