Hydrogen-bonded linear chain assemblies of palladium(ii)-selenoether complexes: solid state aggregates as templates for nano-structural Pd17Se15 leading to efficient electrocatalytic activity

Abstract

A analogous series of 2-(3,5-dimethylpyrazol-1-yl)phenyl substituted selenoether complexes of palladium [PdCl₂(RSeC₆H₄dmpz)]; (R = CH₂COOH (1), CH₂CH₂COOH (2), and CH₂CH₂OH (3); dmpz = dimethylpyrazole) were ably synthesized in a facile manner and exhaustively characterized. Insight into molecular structures of these complexes was keenly probed through single crystal X-ray diffraction (XRD) analysis, unfolding the structural scaffolds and laying into molecular aggregation, availed through hydrogen bonding interactions borne out of tethered protic groups. The complexes were converted to capping free palladium selenide (Pd₁₇Se₁₅) nanoparticles through pyrolysis and evaluated for their electrocatalytic efficacy towards the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) in alkaline medium. In an alkaline medium, PSNP1 (Pd₁₇Se₁₅) obtained from the hydrogen bonded aggregate of complex PdCl₂L₁ (1) produced good HER activity. PSNP1 had a little decrease in current density after 300 continuous cycles, which proves that the catalyst presents high stability in the recycling process. For the electrocatalytic oxidation of CH₃OH, the electrocatalytic rate constant (k) obtained was 0.3 × 10³ cm³ mol⁻¹ s⁻¹.