In-situ template cooperated with urea to construct pectin-derived hierarchical porous carbon with optimized pore structure for supercapacitor

•The 3D hierarchically porous carbon were synthesized via in-situ template and KOH activation from pectin.•The activation temperature and the addition of urea can adjust the content of heteroatoms and the pore structure.•The in-situ hard template can adjust the micropore/mesopores ratio.•The high specific surface area and its suitable micropore/mesopores ratio are helpful to promote charge storage and ion transfer. Pectin as a functional biopolymer has been successfully exploited to produce N/O co-doped 3D carbon architecture with hierarchical pores. A simple and novel in-situ template combining with KOH activation method is utilized to prepare porous carbon using calcium acetate as the template source and urea as a dopant. The in-situ CaCO3 template, activation temperature and urea additive have a significant influence on the morphology, pore structure and performance of porous carbon. The high specific surface area of NHPC-700 (2928 m2g − 1) and its suitable micropore/mesopores ratio are helpful to promote specific capacitance and rate performance. The NHPC-700 possesses the high specific capacitance of 338 F g − 1 at 1 A g − 1 and the excellent capacitance retention of 83% from 1 A g − 1 to 50 A g − 1. Furthermore, the NHPC-700 symmetric supercapacitor shows an energy density of 22.4 Wh kg−1 at 880 W kg−1 in 1 M Na2SO4. The efficient use of pectin to synthesize functionalized hierarchical porous carbon materials has a broad development prospect. [Display omitted]