Silicon oxycarbide-derived hierarchical porous carbon materials for rhodamine B and CO 2 adsorption

The hollow mesoporous silicon oxycarbide (SiOC) ceramics without mixed Si−O−C units (SiO 2 /C composites) were synthesized through the solvothermal route in Na 2 CO 3 solution, and porous carbon materials were prepared by HF etching. Amorphous SiO 2 is transformed into cristobalite SiO 2 as the increase in pyrolysis temperature from 1000 to 1400 °C, while the free C (C free ) content decreases as the elevation of pyrolysis temperature. The carbothermal reduction reaction of SiO 2 with C free not only results in the formation of SiC nanowires, but also further reduces the C content. However, after HF etching, the C content in carbon materials increases as elevation of pyrolysis temperature, and more micro-/mesopores are created by removal of SiO 2 . The microstructure and porosity of carbon materials are tailorable by simple changing the pyrolysis temperature. Furthermore, the HF etching results in the insertion of F only in SiO 2 and which has no effect on the C free . The hierarchical porous structure in conjunction with surface oxygen-containing functional group make the carbon materials obtained at 1400 °C exhibit the good rhodamine B (RhB) and CO 2 adsorption performance. The maximum RhB and CO 2 adsorption capacity is 130.9 mgg −1 and 1.31 mmolg −1 , respectively. Graphical Abstract