Coupling Bimetallic Oxides/Alloys and N-Doped Carbon Nanotubes as Tri-Functional Catalysts for Overall Water Splitting and Zinc-Air Batteries

Qing Qin; Ping Li; Lulu Chen; Xien Liu

doi:10.1021/acsami.8b15612

Coupling Bimetallic Oxides/Alloys and N-Doped Carbon Nanotubes as Tri-Functional Catalysts for Overall Water Splitting and Zinc-Air Batteries

ACS Appl Mater Interfaces. 2018 Nov 21;10(46):39828-39838. doi: 10.1021/acsami.8b15612. Epub 2018 Nov 12.

Authors

Qing Qin¹, Ping Li¹, Lulu Chen¹, Xien Liu¹

Affiliation

¹ State Key Laboratory Base of Eco-Chemical Engineering, College of Chemistry and Molecular Engineering , Qingdao University of Science & Technology , Qingdao 266042 , P. R. China.

PMID: 30376289
DOI: 10.1021/acsami.8b15612

Abstract

An effectively multifunctional electrocatalyst is crucial for catalyzing the reactions occurred at electrodes in zinc-air batteries and water splitting cells, such as oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and oxygen reduction reaction (ORR). Herein, two non-noble metal-based multifunctional electrocatalysts of N-doped carbon nanotubes NCNT/CoFe-CoFe₂O₄ and NCNT/MnO-(MnFe)₂O₃ are prepared by a simple solvothermal procedure, followed by two-step annealing under the argon and ammonia atmosphere. The resultant electrocatalysts exhibit good trifunctional performances for HER, ORR, and OER. Notably, the NCNT/CoFe-CoFe₂O₄ and NCNT/MnO-(MnFe)₂O₃ assembled zinc-air batteries exhibit high energy densities of 727 and 776 W h kg_Zn^-1 at the current density of 20 mA cm^-2, respectively. Furthermore, the NCNT/CoFe-CoFe₂O₄-based rechargeable zinc-air battery remains excellent durability after discharge-charge cycle testing for 22 h, comparable to the noble metal-based catalyst (Pt/C + IrO₂)-assembled zinc-air battery. Furthermore, the NCNT/CoFe-CoFe₂O₄ and NCNT/MnO-(MnFe)₂O₃-assembled water splitting cells need ∼1.65 and 1.70 V, respectively, to deliver a current density of 10 mA cm^-2, lower than that of IrO₂-Pt/C (1.71 V) and present excellent durability under long-term electrolysis. This work provides a facile strategy to prepare highly active multiple functional electrocatalysts for energy conversion and storage.

Keywords: hydrogen evolution reaction; oxygen evolution reaction; oxygen reduction reaction; water splitting cell; zinc−air battery.