Electrocatalytic Behavior of an Amide Functionalized Mn(II) Coordination Polymer on ORR, OER and HER

Abstract

The new 3D coordination polymer (CP) [Mn(L)(HCOO)]n (Mn-CP) [L = 4-(pyridin-4-ylcarbamoyl)benzoate] was synthesised via a hydrothermal reaction using the pyridyl amide functionalized benzoic acid HL. It was characterized by elemental, FT-IR spectroscopy, single-crystal and powder X-ray diffraction (PXRD) analyses. Its structural features were disclosed by single-crystal X-ray diffraction analysis, which revealed a 3D structure with the monoclinic space group P21/c. Its performance as an electrocatalyst for oxygen reduction (ORR), oxygen evolution (OER), and hydrogen evolution (HER) reactions was tested in both acidic (0.5 M H2SO4) and alkaline (0.1 M KOH) media. A distinct reduction peak was observed at 0.53 V vs. RHE in 0.1 M KOH, which corresponds to the oxygen reduction, thus clearly demonstrating the material’s activity for the ORR. Tafel analysis revealed a Tafel slope of 101 mV dec−1 with mixed kinetics of 2e− and 4e− pathways indicated by the Koutecky–Levich analysis. Conversely, the ORR peak was not present in 0.5 M H2SO4 indicating no activity of Mn-CP for this reaction in acidic media. In addition, Mn-CP demonstrated a noteworthy activity toward OER and HER in acidic media, in contrast to what was observed in 0.1 M KOH.

Catalyzing towards clean energy: tuning the oxygen evolution reaction by amide-functionalized Co(ii) and Ni(ii) pristine coordination polymers

“…28 In a prior study, we reported several CPs derived from amide-functionalized ligands that exhibited remarkable activity in C-C coupling reactions, dye adsorption, supercapacitors and electrocatalysts for the OER and overall water splitting. [29][30][31][32] Distinguished by well-defined structures and tunable properties, these materials present a promising avenue to address challenges associated with conventional catalysts. The intricate interplay between metal centers and organic ligands in CPs/MOFs yields tailored active sites that can enhance OER kinetics.…”

“…In our previous work, we systematically changed the position of the pyridine nitrogen atom in amide-based ligands, creating CPs capable of catalysis, 29 dye adsorption, 30 water splitting, 31,32 and supercapacitance. 31 The present study presents a novel amide-based multifunctional proligand, 4-(pyrimidin-5-ylcarbamoyl)benzoic acid (HL, Scheme 1), with a pyridinium moiety.…”