I am trying to synthesize graphitic carbon nitride (g-C3N4) from Urea by pyrolysis. I used an alumina crucible with lid, and heated 10g Urea to 550oC and maintained at this temperature for 3 hours. According to a published paper, I'm supposed to get 4% yield. But my end product (yellow colored powder/flake) was only 0.015g. Please let me know how the yield can be enhanced. Thank you!