Electrocatalytic Behavior of an Amide Functionalized Mn(II) Coordination Polymer on ORR, OER and HER
Anup Paul,
Kristina Radinović,
Susanta Hazra,
Dušan Mladenović,
Biljana Šljukić,
Rais Ahmad Khan,
Maria Fátima C. Guedes da Silva,
Armando J. L. Pombeiro
Affiliations
Anup Paul
Centro de Química Estrutura, Institute of Molecular Sciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
Kristina Radinović
University of Belgrade, Faculty of Physical Chemistry, Studentski Trg 12-16, 11158 Belgrade, Serbia
Susanta Hazra
Centro de Química Estrutura, Institute of Molecular Sciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
Dušan Mladenović
University of Belgrade, Faculty of Physical Chemistry, Studentski Trg 12-16, 11158 Belgrade, Serbia
Biljana Šljukić
University of Belgrade, Faculty of Physical Chemistry, Studentski Trg 12-16, 11158 Belgrade, Serbia
Rais Ahmad Khan
Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
Maria Fátima C. Guedes da Silva
Centro de Química Estrutura, Institute of Molecular Sciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
Armando J. L. Pombeiro
Centro de Química Estrutura, Institute of Molecular Sciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
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.
