Mechanisms of the Higher Catalytic Activity of Polymer Forms over Complexes for Non-pyrolytic Mono-1,10-phenanthroline-Coordinated Cu2+ (Cu-N2 Type) in an Oxygen Reduction Reaction

Yaoze Liu; Xinxing Mou; Shengping Yu; Chunchun Zhang; Junxian Chen

doi:10.1021/acs.inorgchem.3c01005

Mechanisms of the Higher Catalytic Activity of Polymer Forms over Complexes for Non-pyrolytic Mono-1,10-phenanthroline-Coordinated Cu²⁺ (Cu-N₂ Type) in an Oxygen Reduction Reaction

Inorg Chem. 2023 Jul 24;62(29):11436-11445. doi: 10.1021/acs.inorgchem.3c01005. Epub 2023 Jul 11.

Authors

Yaoze Liu¹, Xinxing Mou¹, Shengping Yu¹, Chunchun Zhang², Junxian Chen¹

Affiliations

¹ Key Laboratory of General Chemistry of the National Ethnic Affairs Commission, School of Chemistry and Environment, Southwest Minzu University, Chengdu 610041, China.
² Analytical and Testing Center, Sichuan University, Chengdu, Sichuan 610064, P.R. China.

PMID: 37433112
DOI: 10.1021/acs.inorgchem.3c01005

Abstract

In this paper, we have thoroughly investigated the ORR mechanism of non-pyrolytic mono-1,10-phenanthroline-coordinated Cu²⁺ (Cu-N₂ type) complexes and polymers by molecular dynamics and quantum mechanics calculation. In contrast to the complex-catalyzed ORR, which follows a direct four-electron pathway along intermediates of Cu(I)-Phen, the polymer-catalyzed ORR follows an indirect four-electron pathway by intermediates of Cu(II)-Phen. By analyzing the structure, spin population, electrostatic potential (ESP), and density of states, we confirmed that the higher ORR catalytic activity of the polymer is due to the conjugation effect of coplanar phenanthroline and Cu(II) in the planar reactants or at the base of the square-pyramidal intermediates. The conjugation effect allows the highest ESP to be located near the active center Cu(II), while the lower ESPs are distributed on the phenanthroline, which is very favorable for the reduction current. This will serve as a theoretical foundation for the development of new highly efficient ORR non-pyrolytic CuN₂ polymer catalysts.