Research On Preparation Of Carbon-based Catalysts By Solution Plasma System And Their Electrocatalytic Performance

In this work,a series of N-doped and F-doped carbon-based materials were prepared by solution plasma method using pollutants as precursors.The effects of experimental parameters such as different pollutant types and discharge time on the structural composition of carbon materials were explored,the structural composition of the prepared carbon materials was analyzed,and the electrocatalytic activity of the prepared carbon-based materials was evaluated.The effect mechanism of N and F doping on the electrochemical activity was explored.The specific research contents are as follows:（1）Carbon-supported ultrafine titanium dioxide（TiO₂@NC）was prepared by plasma-induced dye dissociation and recombination using dye molecules in methyl orange（MO）,methylene blue（MB）,and rhodamine B（RB）wastewater as nitrogen and carbon sources.The structure characterization and analysis of the obtained TiO₂@NCs were carried out.In one-step synthesis,N-doped carbons are generated from the dissociation and self-assembly of dye molecules by plasma action,and under the action of high energy,TiO₂is sputtered and loaded onto the generated N-doped carbon.（2）The electrochemical activity of TiO₂@NCs was evaluated.Combined with the measured electrochemical activity and structural characterization results,it was found that TiO₂@NC with the highest proportion of graphitic-N exhibited a lower overpotential（325 m V at 10 m A/cm²）in alkaline solution,and excellent durability（over 50,000 s）,and exhibited an overall water-splitting applied potential of 1.71 V.（3）A pulsed power supply was used to generate a solution plasma to induce the dissociation of perfluorooctanoic acid（PFOA）,and the F-containing fragments were grafted onto graphite sheets（F-GS）.The effects of different discharge times and different initial concentrations of PFOA on the F doping rate were explored,and the structural composition of F-GS was analyzed by a series of characterization methods.According to the characterization results,the initial addition amount of pollutant PFOA is positively correlated with the F doping amount in the obtained F-GS material within a certain range.（4）The oxygen evolution reaction（OER）activity of a series of F-GS were evaluated.According to the OER activity test results,the introduction of fluorine can effectively improve the catalytic performance of the graphite sheets.F-GS exhibits catalytic activity comparable to that of noble metal oxide RuO₂,and shows long-term stability of more than 24 h at 10 m A/cm².The reaction mechanism of OER catalyzed by F doping was explained by density functional theory calculation.This study provides a new strategy for the resource utilization of wastewater pollutants containing N and F and the preparation of N,F-doped carbon-based catalysts.