Effect of Heteroatoms on Pseudocapacitance for N/O Co-doped Porous Carbon in an Alkaline Aqueous Electrolyte
Weiwei Zhu, Dekui Shen, Haijiao Xie
Abstract
The primary objective of this investigation is to assess the electrochemical properties of porous carbon, concurrently doped with nitrogen and oxygen, featuring a diverse array of surface heteroatoms. We synthesized this type of porous carbon material from Houttuynia cordata, subjected to procedures of nitrogen infusion and activation. Our findings indicate a strong relationship between the pseudocapacitance of the dually doped porous carbon and the concentration of pyridinic-nitrogen. As the pyridinic-nitrogen content increases, the pseudocapacitance first increases due to the growing tendency of active sites. After the pyridinic-nitrogen/carbon atomic ratio reaches 0.027, the pseudocapacitance decreases because the conductivity of the carbon material decreases. Density functional theory simulations indicate that the band gap of pyridinic-nitrogen-doped graphene is 0.021 eV, which is larger than that of nitrogen-free graphene. The increased band gap makes electronic transitions less likely, and the conductivity decreases.