Synthesis Of Calcium Carbide Based Porous Carbon Materials Through Mechanochemical Reaction

Porous carbon materials(PCM)refer to the materials that use carbon as their basic skeleton with different pore structures.Due to their well-developed pore structure,high specific surface area and good electron conductivity,PCMs are widely used in the fields of adsorption,catalysis,and electrochemistry.As a commercial inorganic material with high carbon content,calcium carbide can be used as a raw material for carbon materials because of its low price and high reactivity.Presently,CaC2 is facing some problems such as excessive production capacity and fewer downstream products.Therefore,development of new applications of CaC2 is of great significance for the well development of the calcium carbide industry.Previous study shows that the mechanical force of ball mill can destroy the crystal structure of CaC2,improve its reactivity,and carbon material with high specific surface area can be synthetized though the ball mill reaction of CaC2 and polyhalogenated species.In order to further study the reactivity of CaO2,find a new method to prepare carbon materials with high application value,we studied its ball mill reaction with 17 new compounds and characterized the PCMs by SEM,XRD,Raman,XPS,BET and TEM.The results show that calcium carbide has high reactivity under ball mill conditions and can react with various anions and some metal cations(even the poorly oxidative Mg2+)to generate PCMs.The carbon content of the PCMs is between 55%-80%.Some heteroatom-doped PCMs were obtained by the reaction of CaC2 and some N-,S-P-bearing compounds.The carbon materials is of mainly disordered structure,and some degree of graphitized structure can be found.All the carbon materials are microporous and mesoporous with varying specific surface area depending on the reactants used.Among them,C-16 has the highest specific area of 591.3 m2.g-1.Cyclic voltammetry and galvanostatic charge-discharge tests were performed on the synthesized carbon materials,and their specific capacitance was calculated.The results show that some of the carbon materials have definite electrochemical properties.Among them,C-16 has the highest specific capacitance of 69.9 F·g-1,while most carbon materials have poor electrochemical performance whit their capacitance below 1 F·g-1.By analyzing the structure-performance relation of the PCMs,it is found that the carbon with higher graphitized structure is favorable to a better electrochemical performance.Adsorption ability of the carbon materials for dibenzothiophene in model oil was studied experimently.The results show that some of the carbon materials have good adsorptive desulfurization performance,and C-1 shows the best desulfurization performance with adsorbance being 19.1 mg·g-1,but most of the carbon materials have poor desulfurization performance.It is found that the adsorption desulfurization performance of the carbon materials is closely related to their specific surface area,and the higher the specific surface area,the better the desulfurization performance.Based on the present study along with the previous results,the enhanced reactity of calcium carbide under ball mill condition is verified,and PCMs with varying constituents and structure may be prepared by ball mill reaction of CaC2 with different compounds.This study gives us a better insight into the calcium carbide chemistry,and provides new ideas for the preparation of PCMs and hetroatom-doped PCMs as well.