Synthesis of nitrogen-doped graphyne/iron catalysts via γ-ray irradiation and their properties

Abstract

In this study, graphdiyne was prepared using a γ-irradiated N-doping photogram to transform two-dimensional graphdiyne into a one-dimensional tubular structure for use as substrate-supported iron nanoparticles for cathodic redox reaction (ORR) in fuel cells. Methods such as scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and isothermal nitrogen adsorption and other characterization methods were used to characterize and analyze the surface morphology, element composition, crystalline structure, and defect degree of the prepared composites. In the alkaline solution, the prepared catalyst was characterized by ORR performance, four-electron selectivity, kinetics and stability via cyclic voltammetry test, linear sweep voltammetry test and electrochemical AC impedance spectroscopy test. The results showed that after γ-ray irradiation, the nitrogen-doped graphite monoalkyne-loaded iron nanoparticle (NGY-Fe) catalyst had a larger specific surface area (411.3 m2/g) and a multilevel pore structure, which was conducive to the exposure of the active center. Moreover, the O2 permeation barrier was decreased, and the ORR activity of the NGY-Fe was significantly improved, especially in terms of the stability and methanol resistance, which were far superior to those of the commercially available commercial Pt/C catalysts.

Keywords

• γ-ray irradiation
• defects
• catalysis
• graphyne
• dope