Low-cost conversion of Mo industrial waste powder into MoO 3 nanobelts catalysts for Oxygen Evolution Reaction

Abstract

Efficient catalysts for electrochemical Oxygen Evolution Reaction (OER) drag a lot of interest in the materials science community since they represent a limiting step in the hydrogen production kinetics during water electrolysis. One of the main goals is developing efficient and sustainable OER catalysts, to replace the currently used platinum group materials (PGMs). Here, we report a low-cost process to produce efficient OER catalysts MoO3 nanobelts from Mo-based powder obtained by industrial waste. Hydrothermal synthesis was conducted at specific pH values using a solution of Mo-based powder and hydrogen peroxide (H2O2), leading to different MoOx nanostructures. Morphological, structural and optical characterizations were performed by using Scanning Electron Microscopy (SEM), Raman Spectroscopy, X-Ray Diffraction (XRD) and Rutherford Backscattering Spectroscopy (RBS), UV-Vis spectrophotometry. OER performances were evaluated with Linear Sweep Voltammetry (LSV), Electrochemical Impedance Spectroscopy (EIS) and Mott-Schottky analysis. Under proper pH condition we obtained MoO3 nanobelts (50–200 nm wide, 10 µm long) showing the best OER performances at 10 mA cm− 2 with overpotential of 324 mV and Tafel Slope of 45 mV dec− 1. The effect of hydrogen peroxide addiction was investigated and a sustainable solution for industrial waste treatment is proposed.