Electrocatalytic and supercapacitor performance of Phosphorous and Nitrogen co-doped Porous Carbons synthesized from Aminated Tannins

Highlights: • Microwave Synthetic technique using aminated tannins is reported for the first time. • P,N doped carbon was characterized extensively for physico-chemical properties. • Cyclic Voltammetry, RDE and RRDE studies were investigated for O₂ reduction capability. • O₂ reduction occurred by a kinetically favored one step four electron reduction pathway. • The charge storage capacity was found to be 161 F/g at 5 mV/S in alkaline conditions. - Abstract: A phosphorus and nitrogen co-doped carbon material (PNDC) was synthesized from aminated tannin and polyphosphoric acid by a rapid and highly efficient microwave synthetic technique. X-ray photoelectron spectroscopy study was useful in the identification of nitrogen and phosphorous environments in a sp² hybridized carbon lattice. The PNDC was found to be a porous material with a surface area of 433 m² g⁻¹. PNDC sample exhibited excellent thermal stability and the Raman spectroscopic studies were used for analyzing defects in the sp² hybridized carbon lattice. This material has promising electrochemical applications, especially for catalyzing oxygen reduction reaction in fuel cells and for charge storage in supercapacitors. The oxygen reduction capability of PNDC was investigated in 0.1 M KOH solution, and rotating disk and ring disk electrode studies were performed to identify the mechanism of oxygen reduction. The capacitative behavior of the PNDC was investigated in 6 M KOH and specific capacitance was determined to be 161 F g⁻¹ due to the electric double layer charge storage phenomenon.