Synthesis and characterization of metal-free nanosheets of carbo-catalysts for bifunctional electrocatalyst towards HER and OER application

•Metal-free electrocatalysts were synthesized from Acorus Calamus.•KOH-activated C-750 shows the presence of 5.9% of the nitrogen atom.•The Raman spectra C-750 activated carbon shows ID/IG ratio is 1.32.•HER results of C-750 reached only low overpotential.•OER results show a small Tafel slope of 0.071 V/dec. Production of “green hydrogen” through water electrolysis is attracting considerable attention in recent years, due to the high demand for green energy technologies. The efficiency of water electrolysis depends on the electrocatalytic activity of anodic and cathodic electrocatalysts. Currently, utilizing Pt and RuO2-based electrocatalysts is expensive in terms of commercial aspects. Therefore, growing research for inventing efficient and cheap electrocatalysts is undergoing rigorously. In this work, we have synthesized, biomass-derived electrocatalysts with intrinsically implanted heteroatoms as hydrogen and oxygen evolution reactions in alkaline electrolytes. The biomass carbon catalyst is derived from the carbonation of the Acorus Calamus plant “root”. The derived carbon is activated by KOH treatment (C-750). The resultant carbon powder is characterized by various physiochemical and electrochemical characterization techniques. The C-750 catalyst is found to have excellent morphology, surface area (3488 m²/g), pore size (4.08 nm), pore volume (1.10 cc/g), and intrinsically doped N. The HRTEM analysis of C-750 reveals well-distributed microporous and graphitic surfaces. When used as an electrocatalyst for HER and OER analysis, the C-750 exhibited appreciable electrocatalytic activity with an overpotential of -0.330 V and 0.563 V vs. RHE, respectively at the current density of -10.0 mA/cm2. In addition, the C-750 catalyst also showed excellent stability with almost zero degradation in a chronoamperometric measurement carried out for 10 hrs. [Display omitted]