O-, meso- and macro-pores along with the Brunauer mmett eller (BET) certain surface area can reach up to 892 m2 g-1 . CO2 sorption analysis shows that numerous ultramicopores (0.6 nm) are present in HPC. Phosphorus prefers to become doped under a high temperature (800 C). Electrochemical measurements in aqueous KOH and H2 SO4 electrolytes reveal that HPCs with similar BET surface regions show fairly unique supercapacitive properties as a Fmoc-Gly-Gly-OH manufacturer consequence of the various ionic sizes of K and SO4 2- . Thinking of the detailed pore-structure parameters and ionic size in aqueous electrolyte, the developed microporosity in HPC8 is conducive for the penetration of SO4 2- compared with HPC6. Configurated with the P-doping and created microporosity, the assembled symmetric supercapacitor can endure a high operation potential of 1.5 V and deliver a high power density of 16.4 Wh kg-1 in aqueous H2 SO4 electrolyte.Nanomaterials 2021, 11,three of2. Experimental Section two.1. Material Preparation Dopamine (hydrochloride), colloid silica (30 wt suspension in water), phytic acid dipotassium salt, and hydrofluoric acid (HF) have been purchased from Sigma Aldrich and used as received without having additional purification. Within a standard experiment, 0.36 g dopamine and 0.09 g phytic acid dipotassium salt were dissolved in 18 mL water by magnetic stirring to form a transparent resolution, then 2 mL colloid silica was added in to the solution. The mixture was magnetically stirred for ten min followed by getting transferred into a plastic beaker and after that immersed in liquid nitrogen and kept for one more ten min. The frozen mixture was then placed inside a freeze-dryer and dried for 24 h. The dried item was further placed in a tube furnace and carbonized at a target temperature (600 and 800 C) for 1 h with a heating price of 2 C min-1 under Ar flow rate of 50 cm3 min-1 . The item was completely washed with HF, deionized water, and ethanol to eliminate the silica and dried within a vacuum oven at 100 C. The obtained porous carbons carbonized at 600 and 800 C were labeled as HPC6 and HPC8, respectively. To investigate the impact of freeze-drying on the porous structure of carbon, the talked about mixture was straight vacuum-dried at 50 C rather of becoming frozen and freeze-dried, followed by carbonized at 800 C. Immediately after the exact same post-treatment procedure, the obtained carbon sample was denoted as C8. two.2. Material Characterization The microstructure of the samples was characterized by X-ray diffraction (