A Cathode Material of Fuel Cells: F-Doped γ-Graphyne/PtPd Nanocomposite from Plasma Activation and Gamma Irradiation

Abstract

γ-Graphyne, a type of carbon material, has become one of the potential candidates for improving fuel cell catalysts, but its large oxygen permeation barrier during the oxygen reduction process hinders the improvement of electrocatalytic performance. In this work, we used plasma fluorination to treat γ-graphyne and combined it with gamma irradiation technology to synthesize F-doped γ-graphyne/PtPd nanoparticle nanocomposite, realizing the first application of γ-graphyne in the field of oxygen reduction catalysis. The as-prepared F-doped γ-graphyne/PtPd catalyst exhibits overall good ORR performance, especially reaching the level of graphdiyne in terms of peak potential, half-wave potential, and current density. Under alkaline conditions, it was comparable to commercial Pt/C and showed more rapid kinetics. Taken together, we found that the high catalytic activity originates from the structural changes that the12-membered ring structure is opened, which is brought about by plasma fluorination treatment and gamma irradiation, which facilitates the diffusion of O2 in the catalytic process, adsorption, and electron transfer of O2 on the surface of the catalyst. The treated γ-graphyne can be a carbon substrate material with high potential in the field of oxygen reduction catalysis.

High-Performance Electrocatalytic CO2 Reduction for CO Generation Using Hydrophobic Porous Carbon Supported Au

“…Similarly, no obvious difference was detected between 20%Au/XC-72, 20%Au/FXC-72, 20%Au/HPC-800, and 20%Au/FPC-800 electrocatalysts. The C 1s spectrum of the series electrocatalysts is depicted in Figure c, in which there was only one single peak at 284.8 eV for 20%Au/XC-72, which was attributed to the C–C/CC species. − After fluorine doping in 20%Au/FXC-72, a new peak centered at 289.4 eV was detected, which was due to the presence of C–F species, − suggesting the fluorine species was successfully involved into the framework of FXC-72. As for the 20%Au/HPC-800 electrocatalyst, besides for the peak centered at 284.8 eV, a peak centered at 287.1 was also observed, which was attributed to the C–O/C–O–C species. − It may be resulted from the residual oxygen of ligand molecules during pyrolysis process.…”

“…The C 1s spectrum of the series electrocatalysts is depicted in Figure c, in which there was only one single peak at 284.8 eV for 20%Au/XC-72, which was attributed to the C–C/CC species. − After fluorine doping in 20%Au/FXC-72, a new peak centered at 289.4 eV was detected, which was due to the presence of C–F species, − suggesting the fluorine species was successfully involved into the framework of FXC-72. As for the 20%Au/HPC-800 electrocatalyst, besides for the peak centered at 284.8 eV, a peak centered at 287.1 was also observed, which was attributed to the C–O/C–O–C species. − It may be resulted from the residual oxygen of ligand molecules during pyrolysis process. However, after fluorine doping in the 20%Au/FPC-800 electrocatalyst, the peak intensity associated to C–O/C–O–C species was significantly weakened because fluorine possesses the strongest electronegativity, which has the priority to bond with carbon.…”

Heteroatom Modified TiO2/Graphene Aerogel Composites by Electron Beam Irradiation in Supercapacitors

“…produces a certain pseudocapacitive behavior and is proven to be an effective way to further improve the capacitive properties of the material. , For example, Sharavath et al, synthesized N-doped TiO 2 /graphene nanocomposites (N-TiO 2 /NG) by hydrothermal method and achieved a specific capacitance of 205.1 F g –1 at 1 mV s –1 and cycling stability of 78.8% after 5000 consecutive charges and discharges at 1 A g –1 , which have more excellent electrochemical properties. In addition, the codoping of two or more elements with different electronegativity (e.g., N, S) causes unique electron distribution and induces structural distortions, resulting in a synergistic effect that can more effectively improve the electrochemical properties of the material. ,, So far, many methods have been used to prepare N, S codoped carbon materials (e.g., hydrothermal/solvothermal reaction, high-temperature calcination, etc. ), but these methods are time-consuming and environmentally unfriendly and require high-temperature reactions.…”

“…In addition, the codoping of two or more elements with different electronegativity (e.g., N, S) causes unique electron distribution and induces structural distortions, resulting in a synergistic effect that can more effectively improve the electrochemical properties of the material. 8,22,23 So far, many methods have been used to prepare N, S codoped carbon materials (e.g., hydrothermal/solvothermal reaction, high-temperature calcination, etc. ), but these methods are time-consuming and environmentally unfriendly and require high-temperature reactions.…”

Ab Initio Dynamics of Graphene and Graphyne Electrodes in Vacuum and in the Presence of Electrolytes

“…Several computational and experimental studies characterizing the structural and energetic properties of graphyne and exploring its applications have been published recently. − In particular, computational studies based on static DFT calculations and/or classical molecular dynamics simulations have provided a precious volume of information about these systems. − Work involving its electronic structure as well as the changes produced by substitutional groups, functionalization, or adsorption of ions has been extensively carried out. ,,,,− Despite this vast volume of information, little is known about the intramolecular dynamics of these materials and the interaction of their electronic density with condensed media. In this work, we obtain this information through ab initio molecular dynamics (AIMD) simulations in which we investigate the structural, spectroscopic, and electronic properties of a graphyne electrode in contact with an ionic liquid (EMIM-BF 4 ), which is a typical electrolyte in electrochemical applications.…”