MoO₃ Nanobelts Synthesized from Recycled Industrial Powder and Applied as Electrodes for Energy Storage Applications

The sustainable development of our society faces significant challenges, including the need for environmentally friendly energy storage devices. Our work is concerned with the conversion of Mo-based recycled industrial waste into active nanocatalysts for energy storage applications. To reach this goal, we employed hydrothermal synthesis, a low-cost and temperature-scalable method. The proposed synthesis produces MoO₃ nanobelts (50-200 nm in width and 2-5 µm in length) with a high yield, about 74%. The synthesized nanostructures were characterized in 1 M KOH and 1 M NH₄OH, as alkaline environments are a promising choice for the development of eco-friendly devices. To investigate the material's behaviour cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements were carried out. From CV curves, it was possible to evaluate the specific capacitance values of 290 and 100 Fg^-1 at 5 mVs^-1 in 1 M KOH and 1 M NH₄OH, respectively. Also, GCD was employed to evaluate the specific capacitance of the material, resulting in 75 and 60 Fg^-1 in 1 M KOH and 1 M NH₄OH, respectively. CV and GCD analyses revealed that MoO₃ nanobelts act as two different types of energy storage devices: supercapacitors and pseudocapacitors. Additionally, EIS allowed us to distinguish between the resistive and capacitive behaviour contributions depending on the electrolyte. Furthermore, it provided a comprehensive electrochemical characterization in different alkaline electrolytes, with the intention of conjugating waste management and sustainable energy storage device production.