Green synthesized N-doped graphitic carbon sheets coated carbon cloth as efficient metal free electrocatalyst for hydrogen evolution reaction

•N-doped graphitic carbon sheets (N-GCSs) were prepared by Rubus parvifolius fruit.•N-GCSs coated carbon cloth (CC) shows good electrocatalytic activity towards HER.•The onset potential of N-GCSs/CC is about −0.25 VRHE.•Tafel slope of N-GCSs/CC is smaller (198 mV dec−1) than bare CC.

Heteroatom doped carbon structures received a great attention owing to its applications in catalysis, energy and optics. In this work, a simple hydrothermal approach for the synthesis of nitrogen doped graphitic carbon sheets (N-GCSs) is reported. Rubus parvifolius (R. parvifolius) fruit juice and aqueous ammonia are used as carbon precursor and nitrogen dopant, respectively. The synthesized N-GCSs are characterized using Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, high resolution transmission electron microscopy (HR-TEM) and field emission scanning electron microscopy (FE-SEM) coupled with energy dispersive spectrum (EDS). The presence of hydroxyl and carbonyl functionalities in the synthesized N-GCSs are confirmed by the FT-IR analysis. The doping of nitrogen in N-GCSs is revealed through the XPS spectrum. The XRD and Raman studies imply that the synthesized N-GCSs are moderate graphitic nature. The FE-SEM and HR-TEM images of N-GCSs exposed its sheet like porous morphology. The electrocatalytic activity of N-GCSs coated carbon cloth (N-GCSs/CC) are examined towards hydrogen evolution reaction (HER) in 0.50 M H2SO4 using linear sweep voltammetry (LSV), Tafel and electrochemical impedance spectroscopy (EIS) studies. The onset potential of synthesized N-GCSs/CC is about −0.25 VRHE, which is lower than that of bare carbon cloth (CC) −0.75 VRHE. The Tafel slope of N-GCSs/CC is smaller (198 mV dec−1) than that of bare CC (253 mV dec−1), suggested fast kinetics of N-GCSs. Moreover, the N-GCSs/CC is attained −10 mA cm−2 of current density at very low over potential of −0.320 VRHE. The EIS studies also proved the excellent catalytic activity of N-GCSs/CC towards HER. Thus, the R. parvifolius derived N-GCSs is a better candidate for HER in acidic medium.

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