High nitrogen-doped porous carbon material from porous aromatic framework; an approach to bi-functional Metal-free electrocatalyst.

[Display omitted] • Azo group (N = N) was used as a source of nitrogen to introduce nitrogen into the porous carbon materials for the first time. • Nitrogen-doped porous carbon materials through pyrolysis of the Azo-bridged calix[4]resorcinarene porous aromatic framework were synthesized and characterized. • Nitrogen-doped porous carbon materials has been utilized for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) This study successfully synthesized nitrogen-doped porous carbon materials through pyrolysis of the azo-bridged calix[4]resorcinarene porous aromatic framework. This was the first time that N was introduced into porous carbon materials by using the azo group (N = N) as a nitrogen source. Nitrogen-doped porous carbon materials (N-C-x) were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and nitrogen adsorption–desorption isotherms. The efficiency of the fabricated electrocatalysts was assessed toward oxygen reduction reaction (ORR) in whole-range pH and oxygen evolution reaction (OER) in the base media. N-C-900 displayed outstanding activity among the prepared samples. In the ORR, the onset potential for N-C-900 was 0.99 V, 0.925 V, and 0.98 V vs. RHE in base, natural, and acidic electrolytes, respectively, which were close to commercial Pt/C in the same electrolyte. In OER, the optimal catalyst N-C-900 had an overpotential of 220 mV and a Tafel slope of 212 mV.dec-1, similar to RuO 2. [ABSTRACT FROM AUTHOR]