The electrocatalytic hydrogen evolution reaction using a heteroatom-doped hollow onion-like fullerene across a wide pH range

Abstract

Electrocatalytic hydrogen production from the water splitting reaction can satiate the global future energy demand. Low-dimensional carbon nanomaterials have attracted the attention of researchers due to their low cost, easy synthetic techniques, high mechanical/chemical stability, remarkable electrical conductivity, large specific surface area, and environmentally benign nature. Specifically, hollow Onion-Like Fullerenes (h-OLFs) with high porosity can be promising metal-free electrocatalysts for the production of green hydrogen. In this work, we report the hydrothermal synthesis of h-OLF in a specific bottom-up method from glucose and sulphanilamide as organic precursors and its subsequent characterization. Upon introducing the h-OLF as a carbon-based cathodic material on the 1 cm² surface of nickel foam, reasonable hydrogen evolution reaction (HER) activity was observed in non-aqueous media containing different amounts of p-toluene sulphonic acid (PTSA), acetic acid (AcOH), sulphate buffer, and dilute HCl as the proton source, giving rise to a very low overpotential (η) of 133 mV to achieve a cathodic current of 10 mA cm⁻² and long-term HER performance, e.g., 30 000 s, while maintaining j_HER > 15 mA cm⁻² under chronoamperometric conditions. The lowest Tafel slope value and low charge transfer resistance (R_ct) indicate the favourable HER electrokinetics of the h-OLF. The highest double-layer capacitance (C_dl) in the dilute HCl-containing non-aqueous electrolyte further implies maximum exposure of the electrochemically active sites, facilitating proton adsorption ont the surface of the h-OLF, showcasing the remarkable HER activity of this unique carbon-based nanomaterial.