In this study, we report a method
for fabrication of rhodium nanoparticles
decorated on graphene oxide (Rh–GO) with high coverage of active
sites of Rh nanospheres (NSs) on GO. It is one of the most pivotal
aspects in the development of novel systems having high electrocatalytic
performance toward overall water splitting reactions and is found
to be better than universally acceptable Pt-based nanoelectrodes.
The synthesis of nanohybrids shows the well-dispersed Rh NSs (∼50
nm) on a few layers of graphene oxide sheets. These as-synthesized
nanomaterials were confirmed by scanning electron microscopy (SEM),
high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron
spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy,
Raman spectroscopy, Brunauer–Emmett–Teller (BET) surface
area measurements, thermogravimetric analysis (TGA), and X-ray diffraction
(XRD) analysis. Furthermore, Rh–GO exhibits significantly improved
electrochemical performance toward electrocatalytic water splitting
reactions, that is, hydrogen evolution reaction (HER) and oxygen evolution
reaction (OER), and it shows exceptionally an ultrasmall overpotential
of 2 mV for the HER, reaching a current density of 10 mA cm–2 with a smaller Tafel slope 10 mV dec–1, and the
OER overpotential reaches 0.23 V at 10 mA cm–2 with
a Tafel slope of 27 mV dec–1. The reduced charge
transfer resistances after Rh NSs decoration on GO which lead to simultaneous
enhancement in feasibility toward interfacial electron transfer, result
in an increase in activity toward overall water splitting reactions
(both HER and OER).