Nitrogen, phosphorus, sulfur tri-doped porous carbon derived from covalent polymer with versatile performances in supercapacitor, oxygen reduction reaction and electro-fenton degradation

Abstract

Versatility in energy storage and electrocatalysis is highly desired in material design due to the capability in simultaneous solving the energy and environment associated issues. The heteroelement doped carbons are traditional energy storage and electrocatalysis materials, so it is significant to further explore their versatilities. Herein, N, P, S tri-doped porous carbon was designed for application in supercapacitors (SCs), oxygen reduction reaction (ORR) and electro-Fenton (EF) via controlled pyrolysis of a covalent triazine polymer precursor. Given the high N, P, S heteroelement contents containing special functionalities and the porous texture with high specific surface area, the tri-doped porous carbon demonstrates abundant electrochemically active sites and therefore considerable capacitive and electrocatalytic capabilities. The symmetric supercapacitor based on the tri-doped carbon material delivers high energy densities in acidic (11.6 Wh kg −1 ) and alkaline (11.3 Wh kg −1 ) electrolytes. Moreover, the tri-doped carbon material also demonstrates superior four electrons (4e − ) ORR catalytic activity in alkaline medium essential for fuel cell, and two electrons (2e − ) ORR catalytic activity toward hydrogen peroxide in acidic medium, which further enables high EF degradation efficiency (98.0% in 150 min) for mixed dyes. This work demonstrates the versatility of N, P, S tri-doped porous carbon in electrochemical energy storage and pollution treatment. • Biomass-derived carbon materials are synthesized via bifunctional-salt activation. • Bifunctional salts are used to regulate heteroatom doping sites and pore structures. • The catalyst with N, P doping site achieves two-electron governed ORR with low AE. • The EF degradation of methyl yellow is up to 98.4% after 60 min with good stability. • The catalyst proves excellent reusability in treating wastewater with mixed dyes.