Electrocatalytic Oxygen Reduction in Alkaline Medium at\xa0Graphene-Supported Silver-Iron Carbon Nitride Sites\xa0Generated During\xa0Thermal Decomposition of Silver Hexacyanoferrate

Beata Dembinska,Adam Szwed,Enrico Negro,Krzysztof Miecznikowski,Pawel J Kulesza,Kamila Brzozowska,Vito Di Noto

doi:10.1007/s12678-018-0501-3

Beata Dembinska, Adam Szwed + Show 5 more

Open Access

https://doi.org/10.1007/s12678-018-0501-3

Copy DOI

Abstract

Silver-iron carbon nitride, which has been prepared by pyrolysis (under inert atmosphere) of silver hexacyanoferrate(II) deposited on graphene nanoplatelets, is considered here as electrocatalyst for oxygen reduction in alkaline medium (0.1 M potassium hydroxide electrolyte) in comparison to simple silver nanoparticles and iron carbon nitride (prepared separately in a similar manner on graphene nanoplatelets). The performance of catalytic materials has been examined using such electrochemical diagnostic techniques as cyclic voltammetry and rotating ring-disk electrode voltammetry. Upon application of the graphene nanoplatelet-supported mixed silver-iron carbon nitride catalyst, the reduction of oxygen proceeds at more positive potentials, as well as the amounts of hydrogen peroxide (generated during reduction of oxygen at potentials more positive than 0.3 V) are lower relative to those determined at pristine silver nanoparticles and iron carbon nitride (supported on graphene nanoplatelets), when they have been examined separately. The enhancement effect shall be attributed to high activity of silver toward the reduction/decomposition of H2O2 in basic medium. Additionally, it has been observed that the systems based on carbon nitrides show considerable stability due to strong fixation of metal complexes to CN shells.Graphical ᅟ

Highlights

Proton-Exchange Membrane Fuel Cells (PEMFCs) are promising environmentally friendly electrochemical devices for energy conversion and are still dominating research on lowtemperature fuel cells, but, in recent years, substantial progress in fabrication and utilization of anion exchange membranesAmong the most widely studied oxygen reduction catalysts in alkaline media are the carbon-supported nitrogen-coordinated iron systems obtained via hightemperature pyrolysis of simple precursors
We address fabrication and physicochemical identity of the graphene-nanoplatelet-supported silver-iron carbon nitride catalytic systems derived from thermal decomposition of silver(I) hexacyanoferrate(II) deposited onto polycarboxylate-functionalized graphene nanoplatelets (GNP)
The resulting material is elucidated for oxygen reduction reaction (ORR) in 0.1 M KOH, and the system’s activity is compared to the performance of pristine silver nanoparticles and iron carbon nitride

Summary

Introduction

Proton-Exchange Membrane Fuel Cells (PEMFCs) are promising environmentally friendly electrochemical devices for energy conversion and are still dominating research on lowtemperature fuel cells, but, in recent years, substantial progress in fabrication and utilization of anion exchange membranesAmong the most widely studied oxygen reduction catalysts in alkaline media are the carbon-supported nitrogen-coordinated iron systems (abbreviated as FeNC) obtained via hightemperature pyrolysis of simple precursors.

Results

Conclusion