Electron transfer number control of the oxygen reduction reaction on nitrogen-doped reduced graphene oxides for the air electrodes of zinc-air batteries and organic degradation

Autor: Chi-Chang Hu, Sheng-Hui Wu, Po-Chieh Li
Rok vydání: 2016
Předmět:
Zdroj: Materials Chemistry and Physics. 183:551-560
ISSN: 0254-0584
DOI: 10.1016/j.matchemphys.2016.09.014
Popis: The mean electron transfer number ( n ) of the oxygen reduction reaction (ORR) on reduced graphene oxide (rGO) is controlled by nitrogen doping for the air electrodes of Zn-air batteries and electrochemical organic degradation. Melamine and pyrrole are employed as the nitrogen sources for fabricating N-doped rGO (N-rGO) by microwave-assisted hydrothermal synthesis (MAHS). The n value of the ORR is determined by the rotating ring-disk electrode (RRDE) voltammetry and is successfully controlled from 2.34 to 3.93 by preparation variables. The N-doped structures are examined by the x-ray photoelectron spectroscopic (XPS) analysis. The morphology and the defect degree of N-rGOs are characterized by high resolution transmission electron microscopy (HR-TEM) and Raman spectroscopy. N-rGOs with high and low n values are employed as the air electrode catalysts of zinc-air batteries and in-situ hydrogen peroxide (H 2 O 2 ) generation, respectively. The highest discharge cell voltage of 1.235 V for a Zn-air battery is obtained at 2 mA cm −2 meanwhile the current efficiency of H 2 O 2 generation in 1-h electrolysis at 0 V (vs. RHE) reaches 43%. The electrocatalytic degradation of orange G (OG), analyzed by UV-VIS absorption spectra, reveals a high decoloration degree from the relative absorbance of 0.38 for the azo π-conjugation structure of OG.
Databáze: OpenAIRE
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