Portal de Periódicos da CAPES

On the flexibility of the carbon skeleton

1993; Royal Society of Chemistry; Volume: 89; Issue: 6 Linguagem: Inglês

10.1039/ft9938900935

1364-5455

Jacob E. Koresh,

Diamond and Carbon-based Materials Research

The rigid matrix of amorphous carbon which is composed of disperse graphitic layers responsible for both constrictions and wider pores is found to be somewhat flexible. Nitrogen which is a non-swelling molecule could easily dilate critical constrictions in low-activated carbons. Low-pressure hystereses are observed for nitrogen isotherms at 77 K on these carbons. Study of the nitrogen hystereses of gradually activated ultramicroporous carbon fibres shows that air at 400 °C activates the carbon much more vigorously than CO2 and steam at 800 °C. It is shown that air activation produces heterogeneous carbon with unactivated regions inside the fibres, while CO2 and steam homogeneously activate all the carbon matrix.