Graphene Oxide Decorated with Rh Nanospheres for Electrocatalytic Water Splitting

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 (similar to 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).