Preparation of tungsten oxide nanoparticles modified graphenized pencil lead electrode: An efficient electrocatalyst for water splitting in alkaline medium

Developing efficient heterogeneous electrocatalysts for oxygen evolution reaction (OER) is a critical component for water splitting technology [1-3]. In this study tungsten oxide nanoparticles were electrodeposited on the surface of graphenized pencil lead electrode (GPLE) as a low cost and efficient electrocatalyst for the OER in alkaline media. The prepared tungsten oxide modified GPLE (WO3/GPLE) was carefully characterized by scanning electron microscopy, energydispersive X-ray spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry techniques. The WO3/GPLE exhibits excellent performance in electrocatalytic water oxidation in alkaline media due to synergistic effects arising from the GPLE and WO3 nanoparticles. The developed electrocatalyst represents remarkably low OER overpotential of 1.38 V (vs. RHE) at the current density of 10 mA cm-2 and Tafel slope of 89 mV dec-1 in 1 M KOH solution. The WO3/GPLE was highly stable and capable for maintaining catalytic activity for at least 5 h. Due to distinctive electrical conductivity, high mass transfer, and adequate active sites of GPLE, the electrocatalytic activity of the WO3 nanoparticles were incredibly improved in WO3/GPLE.