When pyrolyzing carbon or metal oxide/carbon precursor, why it is needed to rise to a certain relatively low temperature, hold the temperature for some time, and then rise to a high timperature, hold again. What is the advantage compared with directly raising the temperature to the highest and hold ?
Like the description in the paper (JACS 137.7 (2015): 2688-2694):
The homogeneous compound was placed in the crucible and calcined at
600 °C in a type furnace for 1 h in N2 atmosphere. The parent material
placed was further raised to 800 °C at a ramp of 2.5 °C min−1 and kept
at 800 °C for 1 h in N2 atmosphere.
Pyrolysis requires heating the hydrocarbon in an inert environment (such as nitrogen) sometimes with steam to thermally decompose the material without reaching complete combustion. To reduce the thermal stresses on the pyrolyzer's material, heating is done gradually and ramped in steps to minimize thermally-induced stresses.
Hope this helps answer your question.
Professor Yehia Khalil
Yale University
USA
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