2.3. Preparation of Self-Nitrogen-Doped Porous Carbons (SNPCs)

P(1,5-DANPh) and KOH were ground in a ratio of 1:4 by a regular blender and then the mixture was placed directly in vacuum oven overnight. The carbonization and activation processes were carried out semitonally in furnace tube for one hour at various temperatures (600, 700, and 800 °C) under nitrogen with temperature rate of 5 °C min⁻¹. After cooling the furnace to RT, the product was collected and dispersed in 1M of HCl with stirring for 2 h at 50 °C followed by filtration and washing several times with distillated water until neutral pH for the filtrate. The product (SNPCs) was dried in a vacuum oven overnight at 80 °C. The prepared samples are referred to as SNPCs-6, SNPCs-7 and SNPCs-8.