An Efficient Non-Precious Bifunctional Electrocatalyst Based on 1D/3D Hybrid Nanostructures of Copper Hexacyanoferrate/Multiwalled Carbon Nanotubes Towards Oxygen Electrocatalysis

Abstract

Development of efficient non-precious metal-based catalyst for oxygen reduction and evolution reactions is crucial for various electrochemical energy conversion and storage devices. Prussian blue and its analogues have attracted attention due to their suitable properties including abundant metal centers, porous 3D framework, tunable morphology, ease of synthesis and cost effectiveness. However, poor conductivity and low chemical stability in harsh conditions hinders their practical application. To overcome the limitations, functionalized multi-walled carbon nanotubes have been incorporated with the CHF by simple hydrothermal approach and the catalyst was checked for ORR and OER activity. The electrocatalyst exhibit onset potential of 0.79V vs RHE and achieved steady state current density of 4mA cm-2 at 1600 rpm ,also showing better durability and methanol tolerance as compared to commercially used 20 wt% Pt/C catalyst, making it a good alternative for solid oxide fuel cells . Along with that a good OER activity , showing 10mAcm-2 at 1.72V vs RHE was also observed. The improved performance as compared to pristine CHF and f-CNT can be assigned to the synergistic effect between CHF and f-CNT attributed to the catalytic centers of Cu and C from the parent materials for oxygen species adsorption as well as the interlinked structure of 3D CHF and 1D MWCNT for effective electron transport to the catalytic centers for oxygen electrocatalysis. The study also focuses on the material chemistry of the as prepared nanocomposite CHF/f-CNT and supports the above mentioned proposed mechanism by using FTIR, Raman and XPS techniques. This work provides a simple and efficient method to synthesize multiwalled carbon nanotube supported copper hexacyanoferrate catalyst as an efficient non-precious electrocatalyst for Oxygen electrocatalysis. Keywords: Copper hexacyanoferrate, multi-walled carbon nanotubes, functionalized, oxygen electrocatalysis, non-precious metal