氯气刻蚀中孔碳化钛制备分等级孔结构炭材料(英文)

Fabrication of hierarchical porous carbide-derived carbons by chlorination of mesoporous titanium carbides

以钛酸正丁酯为钛源、蔗糖为炭源,采用溶胶-凝胶法制得有机-无机复合干凝胶,后经高温炭热反应、氯气化学刻蚀分别得到中孔碳化钛及碳化物基炭材料(CDCs)。通过XRD、Raman、SEM、TEM和氮气吸附等表征,考察了钛酸正丁酯/蔗糖摩尔比例(R)对所制碳化钛和CDCs的孔结构和物理特性的影响。结果表明:在碳热过程所形成的中孔和大孔孔隙能够在氯气刻蚀过程中保持并传递给最终的炭材料。所制CDCs具有三种不同层次的孔隙结构,分别为氯气刻蚀碳化钛晶体所产生的微孔、源自蔗糖残留炭中所含的3nm～4nm中孔以及炭颗粒间相互叠加和连接所形成的大孔。通过改变R比值,所制CDCs的BET比表面积和孔容分别在1479m2/g～1640m2/g和1.06cm3/g～2.03cm3/g之间可调。

Mesoporous titanium carbides were prepared via carbotherrnal reduction of organic-inorganic gels using titanium n-butoxide as a Ti source and sucrose as a carbon precursor. The as-made titanium carbides were used as starting materials for producing carbide-derived carbons （CDCs） through thermochemical treatment in a chlorine environment. The influence of the ratio of titanium n-butoxide to sucrose （R） on the porous structure and physical properties of the mesoporous titanium carbide and the resulting CDCs were investigated using X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy, and N2 adsorption. It was found that mesoporosity and macroporosity developed in the course of the formation of the titanium carbides can be preserved and transmitted to the carbon material after chlorine treatment, while microporosity was formed by extraction titanium atoms from the carbide. The obtained CDCs have a hierarchical structure of multiscaled pores, including uniform micropores produced from carbides, mesopores with diameter of 3-4nm original from the residual free carbon and macropores formed by interconnection and overlapping of the carbon particles. By changing the R, the Brunauer-Emmett-Teller specific surface areas and total pore volumes of the CDCs could be adjusted in the range of 1479-1 640 m^2/g and 1.06-2.03 cm^3/g, respectively. These hierarchical porous carbons would have potential applications for use in catalysis, adsorption, gas separation, and electrochemical energy storage.