Bioinspired Copper Coordination Polymer Catalysts for Oxygen Reduction Reaction

Abstract

Non–noble metal catalysts have recently emerged as promising alternatives to the expensive platinum catalysts for the oxygen reduction reaction (ORR). In this study, a new domain of materials, copper based coordination polymers, has been investigated as promising catalysts for ORR. The study was inspired by copper incorporating biomolecules, which efficiently catalyse the oxygen reduction reaction in nature. Two coordination polymers, [Cu2(μ−AcO)4Po)]n (shortened as[Cu–A]) and [Cu2(μ−BzO)4Po)]n (shortened as[Cu–B]), incorporating one–dimensional chains of Cu(II) paddle wheel units bridged with phosphineoxide ligands were combined with multi−walled carbon nanotubes (MCNTs) to prepare hybrid electrocatalysts for ORR. The electrochemical analysis demonstrates that [Cu–A] catalyses ORR with 3.24 numbers of electrons with Tafel slopes of 122/83 mV dec−1 while it is 2.37 numbers of electrons with Tafel slopes of 131/84 mV dec−1 for [Cu–B]. Rotating disk electrode measurements and evaluation of Tafel slopes reveal that acetate moieties attached to Cu site shift the onset potential of ORR anodically (ca. 40 mV) compared to the one with benzoate bridging groups. The effect of bridging ligands to the stability and activity of catalysts in alkaline media was also evaluated. This study opens a new perspective for the development of non–platinum ORR catalysts.

A Versatile Approach to Access Trimetallic Complexes Based on Trisphosphinite Ligands

“…At variance, reaction with CuCl, led to the formation of an insoluble white solid upon concentration of the resulting dichloromethane solution under vacuum. This may result from the formation of a coordination polymer (4a) based on the binding of two phosphinite ligands to each of the copper atoms, as previously reported for polydentate phosphines [45][46][47][48], and even for a related bisphosphinite ligand [49]. This solid could be conveniently washed with hexane and dissolved in CDCl 3 to be characterized by NMR spectroscopy, though subtle variations in temperature or concentration caused the formation of less tractable viscous solutions.…”

Structural, Optical, Electrical and Electrocatalytic Activity Properties Of Luminescent Organic Carbon Quantum Dots

“…The numbers of electrons involved in the ORR and Tafel slope were estimated using this data and summarized in Table (Detail calculation process is described in the Supporting Information (SI)). Based on the number electrons involved in the ORR at the C qdots‐CNT/GC from Figure (c), two pathways of ORR mechanism can be predicted i. e. parallel (k 1 =k 2 and k 3 =0) and serial (k 2 =2×k 3 and k 1 =0) pathways shown in (Scheme S1) . However, these parameters estimated for the CNT/GC demonstrate that the ORR follows the serial pathway (k 2 =k 3 and k 1 =0) favourably with ca.…”

“…Based on the number electrons involved in the ORR at the C qdots-CNT/GC from Figure 9(c), two pathways of ORR mechanism can be predicted i. e. parallel (k 1 = k 2 and k 3 = 0) and serial (k 2 = 2 3 k 3 and k 1 = 0) pathways shown in (Scheme S1). [43] However, these parameters estimated for the CNT/GC demonstrate that the ORR follows the serial pathway (k 2 = k 3 and k 1 = 0) favourably with ca. 2 electron process.…”

Sodalite‐type Cu‐based Three‐dimensional Metal–Organic Framework for Efficient Oxygen Reduction Reaction

“…and Kharwar et al. used one‐dimensional copper‐based coordination polymers for effective ORR catalysts …”

“…Recently Mishra et al and Kharwar et al used one-dimensional copper-basedc oordination polymers for effective ORR catalysts. [25][26][27][28] In the search of better sustainable green ORR catalystf or the fuelc ell to replace the platinum catalyst, we have synthesized ac atalyst, which mimics the enzyme oxygen activation. Here we have reported at hree-dimensional Cu-based MOF ([(Cu 4 Cl) 3 (H 0.5 BTT) 8 (H 2 O) 12 ]·3MeOH·9DMF) with tetrazole ligand (H 3 BTT = 5,5'-(1,4-phenylene) bis(1H-tetrazole)).…”