Synthesis of monolithic macroporous carbon xerogels from phenol, m-cresol, furfural and phosphoric acid by sol-gel approach

Mixtures of phenol and m-cresol in 1-propanol were first reacted with phosphoric acid and then with furfural to form gels, which were dried under ambient pressure and pyrolyzed under nitrogen atmosphere to form monolithic macroporous carbon xerogels. The molar ratio of m-cresol to phenol (m-C/P), phenol and m-cresol to furfural ((m-C+P)/F), phenol and m-cresol to phosphoric acid ((m-C+P)/H(3)PO4) was fixed at 1:5, 1:2 and 4.0 respectively while the m-C+P+F in 1-propanol was changed from 18 to 30 g/100ml to investigate the effect of the m-C+P+F concentrations on the porous properties of the monolithic carbon xerogels. It is found that the surface areas of the monolithic carbon xerogels are mainly contributed by micropores and their mesopore volumes are negligible. The monolithic carbon xerogels are rich in macropores whose sizes decrease from 4 to 0.22 mu m with increasing m-C+P+F concentrations. Moreover, the yields of the monolithic carbon xerogels are around 60%, which is higher than previous ones without phosphoric acid.