Regio-isomerism directed electrocatalysis for energy efficient zinc-air battery
Sanchayita Mukhopadhyay,
Mruthyunjayachari Chattanahalli Devendrachari,
Sandeep C. Kanade,
Chathakudath Prabhakaran Vinod,
Harish Makri Nimbegondi Kotresh,
Musthafa Ottakam Thotiyl
Affiliations
Sanchayita Mukhopadhyay
Department of Chemistry and Centre for Energy Science, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pune 411008, India
Mruthyunjayachari Chattanahalli Devendrachari
Department of Chemistry and Centre for Energy Science, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pune 411008, India
Sandeep C. Kanade
Department of Chemistry and Centre for Energy Science, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pune 411008, India
Chathakudath Prabhakaran Vinod
Catalysis and Inorganic Chemistry Division, CSIR-NCL, Pune 411008, India
Harish Makri Nimbegondi Kotresh
Department of Chemistry, Acharya Institute of Technology, Soldevanahalli, Bangalore 560107, India
Musthafa Ottakam Thotiyl
Department of Chemistry and Centre for Energy Science, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pune 411008, India; Corresponding author
Summary: We have investigated the role of ligand isomerism in modulating the mechanisms and kinetics associated with charge/discharge chemistry of an aqueous metal-air battery. The dominant electron-withdrawing inductive effect (-I effect) and the diminished electron-withdrawing resonance effect (-R effect) in the α-NO2 isomer noticeably diminishes the rate of oxygen reduction (ORR) and oxygen evolution reactions (OER) on the catalytic Co-center. In their β-counterpart, the cumulative –I and –R effects noticeably enhance the OER and ORR kinetics on the same catalytic Co-center. Therefore, the regioisomerism of the -NO2 functionality amplifies the kinetics of ORR/OER without influencing their mechanistic pathways. When isomeric electrocatalysts are integrated to aid the charge chemistry of a Zn-air battery, the overpotential could be decreased by ∼250 mV with β-NO2 isomer leading to a round-trip efficiency as high as 60%. This work contributes to the design of novel molecular platforms to target the overall round-trip efficiency of energy storage and conversion devices.