Multiwalled carbon nanotubes grown over green iron nanocatalyst as electrode for hydrogen-producing electrochemical cell

In order to develop sustainable and renewable energy sources, novel approaches to design noble metal-free efficient electrocatalysts such as carbon and metal dichalcogenides nanostructures are being investigated for hydrogen evolution reaction (HER). In the present work, we successfully synthesize iron nanoparticles (Fe–GT) via facile green approach without using any surfactant and for the first time, green-synthesized iron nanoparticles are utilized as catalysts for production of multiwalled carbon nanotubes (MWCNTs). The synthesized MWCNTs (GT) were characterized using SEM, TEM, XRD and Raman spectroscopy techniques. The MWCNTs (GT)-coated conducting carbon paper electrode was applied as non-precious metal electrocatalyst for HER. The MWCNTs (GT) electrode demonstrates improved electrochemical activity towards HER with a smaller value of Tafel slope ~ 105 mV dec− 1 and overpotential (η10) ~ 192 mV, which is quite comparable to other reported metal-free HER catalyst. We also designed an indigenous electrochemical cell and showed the hydrogen production and collection using MWCNTs (GT) as cathode.