Monitoring of N-doped organic xerogels pyrolysis by TG-MS

作者：Vesela Petra^*; Slovak Vaclav

来源：Journal of Thermal Analysis and Calorimetry, 2013, 113(1): 209-217.

DOI：10.1007/s10973-012-2923-0

• N-doped organic/carbon xerogels
• Nitrogen incorporation
• Pyrolysis
• TG-MS

Pyrolysis of N-doped organic xerogels prepared from different N-containing precursors has been studied by TG-MS. The pyrolytic process has been ascertained to consist of three steps. The first step (up to cca. 250 A degrees C) has been interpreted as water loss (humidity, fixed water from pores) and in some cases as formaldehyde loss. The second step has been connected with volatile substances evolution (cca. 250-450 A degrees C) with predominant release of NH3, CO2 and products of melamine (M) or urea decomposition. Reaction/pore water and formaldehyde have also been detected in this step. The third step of pyrolysis (450-1,000 A degrees C) has been ascribed to carbonization reaction when the other releases of NH3, CO2, reaction/pore water and M decomposition products have continued. This was accompanied with evolution of H-2 and 3-hydroxypyridine. On the basis of TG measurements, it was found that increasing time of condensation of organic xerogels and amount of used catalyst lead to higher yield of carbonaceous products. In addition, adsorption experiments of Pb(II) on N-doped carbon xerogels proved that relationship between adsorption properties of xerogels and nitrogen loss during pyrolysis exists. When the sample contains only amino groups, they are lost during pyrolysis as ammonia and the adsorption ability is low, while nitrogen comprised in the aromatic rings of N-precursors stays in the structure and causes enlarging of adsorption capacity.

• 出版日期2013-7