A Catalyst-Free Preparation of Conjugated Poly Iron-Phthalocyanine and its Superior Oxygen Reduction Reaction Activity

TY - JOUR

T1 - A Catalyst-Free Preparation of Conjugated Poly Iron-Phthalocyanine and its Superior Oxygen Reduction Reaction Activity

AU - Kumar, Anuj

AU - Yasin, Ghulam

AU - Tabish, Mohammad

AU - Kumar Das, Dipak

AU - Ajmal, Saira

AU - Kumar Nadda, Ashok

AU - Zhang, Guoxin

AU - Maiyalagan, T.

AU - Saad, Ali

AU - K. Gupta, Ram

AU - M. Makhlouf, Mohamed

AU - Ibraheem, Shumaila

PY - 2022/5/6

Y1 - 2022/5/6

N2 - Although Fe-phthalocyanine (FePc) has undergone extensive chemical modifications to realize improved oxygen reduction reaction (ORR), its superior performance has yet to be demonstrated at a practical level. Herein, a conjugated poly-FePc was prepared via microwave-assisted polymerization of 1,2,4,5-tetracyanobenzene in presence of FeCl 2. The characterization results of multiple spectroscopic techniques indicated that poly-FePc and monomeric FePc possessed similar structural features, proving that the polymerization process was successful. Further, the prepared poly-FePc was tested for ORR in 0.1 M KOH electrolyte and compared with the traditional 20% Pt/C and monomeric FePc catalysts. Poly-FePc was found to be the best ORR catalyst among studied electrocatalysts, displaying 258 and 40 mV positive shifts in half-wave potential compared with FePc and 20% Pt/C, respectively. The theoretical studies suggested that the large conjugation in poly-FePc down-shifted the energy of the dz 2-orbital of Fe closer to the π*-orbital of O 2 (as also supported by the anodic shift in Fe 3+/Fe 2+ redox potential after polymerization), which allowed for an optimal coupling between these orbitals and therefore followed the 4e- ORR pathway. This study found that adjusting the electronic structures of the active sites of electrocatalysts might have improved their performance.

AB - Although Fe-phthalocyanine (FePc) has undergone extensive chemical modifications to realize improved oxygen reduction reaction (ORR), its superior performance has yet to be demonstrated at a practical level. Herein, a conjugated poly-FePc was prepared via microwave-assisted polymerization of 1,2,4,5-tetracyanobenzene in presence of FeCl 2. The characterization results of multiple spectroscopic techniques indicated that poly-FePc and monomeric FePc possessed similar structural features, proving that the polymerization process was successful. Further, the prepared poly-FePc was tested for ORR in 0.1 M KOH electrolyte and compared with the traditional 20% Pt/C and monomeric FePc catalysts. Poly-FePc was found to be the best ORR catalyst among studied electrocatalysts, displaying 258 and 40 mV positive shifts in half-wave potential compared with FePc and 20% Pt/C, respectively. The theoretical studies suggested that the large conjugation in poly-FePc down-shifted the energy of the dz 2-orbital of Fe closer to the π*-orbital of O 2 (as also supported by the anodic shift in Fe 3+/Fe 2+ redox potential after polymerization), which allowed for an optimal coupling between these orbitals and therefore followed the 4e- ORR pathway. This study found that adjusting the electronic structures of the active sites of electrocatalysts might have improved their performance.

KW - Fe-phthalocyanine

KW - Mechanistic study

KW - Oxygen reduction reaction

KW - Poly-FePc

KW - Stability

UR - http://www.scopus.com/inward/record.url?scp=85129772494&partnerID=8YFLogxK

U2 - 10.1016/j.cej.2022.136784

DO - 10.1016/j.cej.2022.136784

M3 - Journal article

SN - 1385-8947

VL - 445

JO - Chemical Engineering Journal

JF - Chemical Engineering Journal

M1 - 136784

ER -