Synergetic Conversion Of Coal Char And Methane And The Prepared Supercapacitor Electrodes

Natural gas?methane is the main component?is an important raw material for the production of H₂ or synthesis gas?CO and H₂?.In particular,the large-scale development of unconventional natural gas such as shale gas has strongly promoted the development of methane conversion technology.Coal char is an important product of coal pyrolysis,and its value-added utilization is of great significance for the grading and efficient conversion of coal.Supercapacitor is a promising energy storage device,presenting great expectation in portable electronic devices,industrial and transportation fields.Carbon materials?e.g.,activated carbon,graphene,carbide derived carbon,etc.?are common electrode materials used for supercapacitors,which have attracted much attention for their low cost,eco-friendly and good capacitance performance.In this paper,co-production of syngas and hybrid carbon materials were achieved by designing and utilizing synergistic conversion of coal char and methane.In terms of the research content,we primarily explored the formation mechanism of synthesis gas in this process,characterized the surface and structural properties of the carbon material formed by the reaction.And the capacitance performance of the carbon material was evaluated as the electrode material of the supercapacitor.In this study,K₂CO₃,Na₂CO₃ and molten salt?mixture of K₂CO₃ and Na₂CO₃?were used as catalysts for synergistic conversion of coal char and methane,and a series of experiments and performance evaluations were performed.When K₂CO₃was used as catalyst for synergistic conversion of coal char and methane,effect of the operating parameters?including the catalyst dosage,feed gas velocity,reaction temperature and time?was investigated and evaluated for the production of synthesis gas.At the same time,cyclic voltammetry,galvanostatic charge/discharge and electrochemical impedance spectroscopy tests were used to evaluate the performance of carbon materials as the supercapacitor electrode material.It was found that K₂CO₃ had a positive effect on both the activation of coal char and the methane conversion.Besides an appropriate amount of synthesis gas production,a hybrid carbon material?mainly consists of the porous carbon formed by the activation of coal char and the carbon formed during the methane conversion?can be obtained with the specific surface area and structural characteristics.When the carbon material was used as the electrode of the supercapacitor,it showed a good capacitance performance.The specific capacitance was up to 125 F/g at a scan rate of 5 m V/s and 133 F/g at a current density of 1 A/g.Based on the good performance of K₂CO₃ as a catalyst,the similar chemicals such as Na₂CO₃and molten salt?a mixture of K₂CO₃ and Na₂CO₃?were also used as a catalyst for the synergistic conversion of coal char and methane,and the related performance was also investigated and evaluated in this study.