Activation of Oxygen Reduction Reaction on Carbon Supported Ni‐Based Complexes. Issue 34 (9th September 2021)

• Record Type: Journal Article
• Authors: Kharwar, Yashwant P.; Gurusamy, Tamilselvi; Mandal, Sudip; Ramanujam, Kothandaraman
• Is Part Of: ChemistrySelect. Volume 6:Issue 34(2021)
• Page Start: 9101
• Page End: 9111
• Publication Date: 2021-09-09
• Subjects: Heterogeneous catalysis -- Supported catalysts -- Ni-based complexes -- Oxygen reduction reaction -- Oxygen adsorption energy (Ead).; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.202101231
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: There are unremitting efforts towards developing an effective oxygen reduction reaction (ORR) catalyst as it is seminal for the commercially viable energy conversion and storage devices such as fuel cell and metal‐air batteries. In this study, three carbon‐supported Ni‐based coordination complexes; Ni‐phen/AC, Ni‐bpy/AC and Ni‐bimz/AC (where phen=1, 10‐ phenanthroline, bpy=2, 2′‐bipyridine and bimz=benzimidazole) were explored for ORR. Among these, Ni‐bimz forms a 1D‐polymer chain via a succinate bridge, and these chains are stacked by the π‐π interactions and hydrogen bonding. The ORR potentials of these catalysts were studied using cyclic voltammetry technique with a rotating ring disk electrode system, and oxygen adsorption energies ( Ead ) onto these complexes were calculated using density functional theory (DFT) analysis. The highest onset potential of 0.89 V vs . RHE was observed for Ni‐bimz/AC, whereas 0.88 V and 0.86 V vs . RHE for Ni‐phen/AC and Ni‐bpy/AC catalysts, respectively. The Ead value for O2 via side‐on and end‐on mode over Ni‐phen, Ni‐bpy, and Ni‐bimz complexes, were calculated. The highest negative Ead value of −25.53 eV via side‐on mode was observed for Ni‐bimz complex. Abstract : Ni‐based complexes with three different N ‐heterocyclic ligands (bimz, bpy and phen) in presence of succinic acid were synthesized and dispersed on the activated carbon (AC). Among the complexes, Ni‐bimz/AC, a 1D polymer chain with succinate bridged, was completely stable in aqueous KOH medium and exhibited a half‐wave potential of 0.81 V vs . RHE whereas Ni‐phen/AC and Ni‐bpy/AC have exhibited 0.79 and 0.78 V respectively at 800 rpm and 5 mVs −1 scan rate in 0.1 M KOH electrolyte.