Electrocatalytic H2O2 production through di-nuclear copper(II) hydroxo bridged complexes with pyrrolidine and piperidine-based ligands

Koyal Pattanaik; Varsha Singh; Suman Bhattacharya; Vellaichamy Ganesan; Shahulhameed Sabiah

doi:10.1016/j.inoche.2025.114854

Electrocatalytic H₂O₂ production through di-nuclear copper(II) hydroxo bridged complexes with pyrrolidine and piperidine-based ligands

Koyal Pattanaik
, Varsha Singh
, Suman Bhattacharya
, Vellaichamy Ganesan
, Shahulhameed Sabiah

Department of Physics

Pondicherry University
Banaras Hindu University

Research output: Contribution to journal › Article › peer-review

Abstract

Hydrogen peroxide (H₂O₂) is one of the most significant molecules with a steadily increasing demand in medicine, chemical synthesis, and environmental protection. The current industrial production of H₂O₂ relies heavily on the anthraquinone process, a complex procedure that involves careful distillation generates hazardous waste, and results in the decomposition of large quantities of H₂O₂ due to its heat instability. The electrochemical process of oxygen reduction provides a highly efficient and ecologically benign method for generating H₂O₂. Two biphenyl anchored di-nuclear copper(II) hydroxo bridged complexes [Cu₂(L1)₂(µ-OH)₂(H₂O)₂](ClO₄)₂, (1) and [Cu₂(L2)₂(µ-OH)₂(H₂O)₂](ClO₄)₂, (2), where L1, 6-(2-(pyrrolidin-1-yl)ethyl)-6,7-dihydro-5H-dibenzo[c,e]azepine and L2, 6(2-(piperidin-1-yl) ethyl)-6,7-dihydro-5H-dibenzo[c,e]azepine, have been synthesized. Various analytical techniques including elemental analysis, UV–Vis, FT-IR, ESI-MS, and thermogravimetry analysis were used to characterize both complexes. X-ray diffraction of complex 1 revealed that the complex is centrosymmetric and di-nuclear with µ-OH bridges. Both units have copper(II) in a distorted square pyramid geometry. The synthesized complexes were immobilized on graphene to obtain Cu-L1 and Cu-L2 composites. These composites were characterized by Powder-XRD, FE-SEM and elemental mapping to ascertain their structural and morphological properties. They show a highly stable two-electron oxygen reduction process with onset potentials of 0.86 and 0.85 V vs RHE (Reversible Hydrogen Electrode). They showed greater electrochemical stability over 2000 CV cycles as analyzed by LSV responses. Further, the XRD patterns recorded before and after catalysis showed no significant changes, indicating that the composite materials remain stable during the ORR process. Additionally, FE-SEM images and the corresponding energy-dispersive X-ray spectroscopy (EDS) obtained before and after catalysis confirm the presence of C, O, N, and Cu.

Original language	English
Article number	114854
Journal	Inorganic Chemistry Communications
Volume	179
DOIs	https://doi.org/10.1016/j.inoche.2025.114854
Publication status	Published - Sept 2025

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This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 12 Responsible Consumption and Production

Keywords

Copper(II) hydroxo bridged complexes
Electrocatalysis
Hydrogen peroxide
Oxygen reduction

Access to Document

10.1016/j.inoche.2025.114854

Cite this

@article{582f54976cf84ea28cd98abcf4f793e6,

title = "Electrocatalytic H2O2 production through di-nuclear copper(II) hydroxo bridged complexes with pyrrolidine and piperidine-based ligands",

abstract = "Hydrogen peroxide (H2O2) is one of the most significant molecules with a steadily increasing demand in medicine, chemical synthesis, and environmental protection. The current industrial production of H2O2 relies heavily on the anthraquinone process, a complex procedure that involves careful distillation generates hazardous waste, and results in the decomposition of large quantities of H2O2 due to its heat instability. The electrochemical process of oxygen reduction provides a highly efficient and ecologically benign method for generating H2O2. Two biphenyl anchored di-nuclear copper(II) hydroxo bridged complexes [Cu2(L1)2(µ-OH)2(H2O)2](ClO4)2, (1) and [Cu2(L2)2(µ-OH)2(H2O)2](ClO4)2, (2), where L1, 6-(2-(pyrrolidin-1-yl)ethyl)-6,7-dihydro-5H-dibenzo[c,e]azepine and L2, 6(2-(piperidin-1-yl) ethyl)-6,7-dihydro-5H-dibenzo[c,e]azepine, have been synthesized. Various analytical techniques including elemental analysis, UV–Vis, FT-IR, ESI-MS, and thermogravimetry analysis were used to characterize both complexes. X-ray diffraction of complex 1 revealed that the complex is centrosymmetric and di-nuclear with µ-OH bridges. Both units have copper(II) in a distorted square pyramid geometry. The synthesized complexes were immobilized on graphene to obtain Cu-L1 and Cu-L2 composites. These composites were characterized by Powder-XRD, FE-SEM and elemental mapping to ascertain their structural and morphological properties. They show a highly stable two-electron oxygen reduction process with onset potentials of 0.86 and 0.85 V vs RHE (Reversible Hydrogen Electrode). They showed greater electrochemical stability over 2000 CV cycles as analyzed by LSV responses. Further, the XRD patterns recorded before and after catalysis showed no significant changes, indicating that the composite materials remain stable during the ORR process. Additionally, FE-SEM images and the corresponding energy-dispersive X-ray spectroscopy (EDS) obtained before and after catalysis confirm the presence of C, O, N, and Cu.",

keywords = "Copper(II) hydroxo bridged complexes, Electrocatalysis, Hydrogen peroxide, Oxygen reduction",

author = "Koyal Pattanaik and Varsha Singh and Suman Bhattacharya and Vellaichamy Ganesan and Shahulhameed Sabiah",

note = "Publisher Copyright: {\textcopyright} 2025",

year = "2025",

month = sep,

doi = "10.1016/j.inoche.2025.114854",

language = "English",

volume = "179",

journal = "Inorganic Chemistry Communications",

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T1 - Electrocatalytic H2O2 production through di-nuclear copper(II) hydroxo bridged complexes with pyrrolidine and piperidine-based ligands

AU - Pattanaik, Koyal

AU - Singh, Varsha

AU - Bhattacharya, Suman

AU - Ganesan, Vellaichamy

AU - Sabiah, Shahulhameed

PY - 2025/9

Y1 - 2025/9

N2 - Hydrogen peroxide (H2O2) is one of the most significant molecules with a steadily increasing demand in medicine, chemical synthesis, and environmental protection. The current industrial production of H2O2 relies heavily on the anthraquinone process, a complex procedure that involves careful distillation generates hazardous waste, and results in the decomposition of large quantities of H2O2 due to its heat instability. The electrochemical process of oxygen reduction provides a highly efficient and ecologically benign method for generating H2O2. Two biphenyl anchored di-nuclear copper(II) hydroxo bridged complexes [Cu2(L1)2(µ-OH)2(H2O)2](ClO4)2, (1) and [Cu2(L2)2(µ-OH)2(H2O)2](ClO4)2, (2), where L1, 6-(2-(pyrrolidin-1-yl)ethyl)-6,7-dihydro-5H-dibenzo[c,e]azepine and L2, 6(2-(piperidin-1-yl) ethyl)-6,7-dihydro-5H-dibenzo[c,e]azepine, have been synthesized. Various analytical techniques including elemental analysis, UV–Vis, FT-IR, ESI-MS, and thermogravimetry analysis were used to characterize both complexes. X-ray diffraction of complex 1 revealed that the complex is centrosymmetric and di-nuclear with µ-OH bridges. Both units have copper(II) in a distorted square pyramid geometry. The synthesized complexes were immobilized on graphene to obtain Cu-L1 and Cu-L2 composites. These composites were characterized by Powder-XRD, FE-SEM and elemental mapping to ascertain their structural and morphological properties. They show a highly stable two-electron oxygen reduction process with onset potentials of 0.86 and 0.85 V vs RHE (Reversible Hydrogen Electrode). They showed greater electrochemical stability over 2000 CV cycles as analyzed by LSV responses. Further, the XRD patterns recorded before and after catalysis showed no significant changes, indicating that the composite materials remain stable during the ORR process. Additionally, FE-SEM images and the corresponding energy-dispersive X-ray spectroscopy (EDS) obtained before and after catalysis confirm the presence of C, O, N, and Cu.

AB - Hydrogen peroxide (H2O2) is one of the most significant molecules with a steadily increasing demand in medicine, chemical synthesis, and environmental protection. The current industrial production of H2O2 relies heavily on the anthraquinone process, a complex procedure that involves careful distillation generates hazardous waste, and results in the decomposition of large quantities of H2O2 due to its heat instability. The electrochemical process of oxygen reduction provides a highly efficient and ecologically benign method for generating H2O2. Two biphenyl anchored di-nuclear copper(II) hydroxo bridged complexes [Cu2(L1)2(µ-OH)2(H2O)2](ClO4)2, (1) and [Cu2(L2)2(µ-OH)2(H2O)2](ClO4)2, (2), where L1, 6-(2-(pyrrolidin-1-yl)ethyl)-6,7-dihydro-5H-dibenzo[c,e]azepine and L2, 6(2-(piperidin-1-yl) ethyl)-6,7-dihydro-5H-dibenzo[c,e]azepine, have been synthesized. Various analytical techniques including elemental analysis, UV–Vis, FT-IR, ESI-MS, and thermogravimetry analysis were used to characterize both complexes. X-ray diffraction of complex 1 revealed that the complex is centrosymmetric and di-nuclear with µ-OH bridges. Both units have copper(II) in a distorted square pyramid geometry. The synthesized complexes were immobilized on graphene to obtain Cu-L1 and Cu-L2 composites. These composites were characterized by Powder-XRD, FE-SEM and elemental mapping to ascertain their structural and morphological properties. They show a highly stable two-electron oxygen reduction process with onset potentials of 0.86 and 0.85 V vs RHE (Reversible Hydrogen Electrode). They showed greater electrochemical stability over 2000 CV cycles as analyzed by LSV responses. Further, the XRD patterns recorded before and after catalysis showed no significant changes, indicating that the composite materials remain stable during the ORR process. Additionally, FE-SEM images and the corresponding energy-dispersive X-ray spectroscopy (EDS) obtained before and after catalysis confirm the presence of C, O, N, and Cu.

KW - Copper(II) hydroxo bridged complexes

KW - Electrocatalysis

KW - Hydrogen peroxide

KW - Oxygen reduction

UR - https://www.scopus.com/pages/publications/105007733893

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DO - 10.1016/j.inoche.2025.114854

M3 - Article

AN - SCOPUS:105007733893

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VL - 179

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