Iron phthalocyanine with coordination induced electronic localization to boost oxygen reduction reaction

Abstract

Iron phthalocyanine (FePc) is a promising non-precious catalyst for the oxygen reduction reaction (ORR). Unfortunately, FePc with plane-symmetric FeN 4 site usually exhibits an unsatisfactory ORR activity due to its poor O 2 adsorption and activation. Here, we report an axial Fe-O coordination induced electronic localization strategy to improve its O 2 adsorption, activation and thus the ORR performance. Theoretical calculations indicate that the Fe-O coordination evokes the electronic localization among the axial direction of O-FeN 4 sites to enhance O 2 adsorption and activation. To realize this speculation, FePc is coordinated with an oxidized carbon. Synchrotron X-ray absorption and Mössbauer spectra validate Fe-O coordination between FePc and carbon. The obtained catalyst exhibits fast kinetics for O 2 adsorption and activation with an ultralow Tafel slope of 27.5 mV dec −1 and a remarkable half-wave potential of 0.90 V. This work offers a new strategy to regulate catalytic sites for better performance.

Coordination Engineering of Single‐Atom Catalysts for the Oxygen Reduction Reaction: A Review

“…[157] Chen et al prepared well-defined Fe single-atom catalyst coordinated with pyrrole-N at room temperature, which showed excellent ORR performance, while other researchers believed that pyridine-N coordinated Fe single atom was the active site. [158] It is worth noting that different parameters (e.g., geometric configuration of the support, N-speciation, crystallinity, valence state of the center metal atom, etc.) can affect the electrochemical performance, and it is hard to change one parameter to a large extent on purpose without influencing the others.…”

Reconstructing 1D Fe Single‐atom Catalytic Structure on 2D Graphene Film for High‐Efficiency Oxygen Reduction Reaction

“…The result signifies the removal of partial edge‐H atoms from the molecular structure of α‐FePc during the synthesis process [16] . In addition, the peak at 1378 cm −1 in the FTIR spectrum of α‐FePc could be attributed to the stretching vibration of Fe−O bond, which is formed due to the natural oxygen affinity of active Fe 2+ ions [17] . The Fe−O peak vanished while two extra peaks at 665 cm −1 and 962 cm −1 (stretching and bending vibrations of Fe−O−Fe bonds, respectively) occurred, suggesting changed Fe−O coordination configuration in Fe SAC@G‐110 [18] .…”

All carbon hybrid N-doped carbon dots/carbon nanotube structures as an efficient catalyst for the oxygen reduction reaction

“…This is because the embedded heteroatoms can alter the local spin or charge density considerably by producing an irregular charge distribution in the adjacent sites, thereby enhancing the electronic conductivity and promoting adsorption and activation of molecular oxygen. 24,25 In the carbon material family, carbon quantum dots (CQDs, C-dots, or CDs) as a new class of zero-dimensional nanocarbon with sizes below 10 nm, showed good solubility, low cytotoxicity, great compatibility, and simple synthesis, and could be functionalized with surface passivation. 26,27 CDs have highly defective oxygen-containing moieties that are distributed randomly at the basal plane and edge sites.…”