Structural, optical, and electrochemical properties of tungsten-doped cadmium zinc phosphate nanoporous materials for energy storage and peroxide detection

Abstract

The demand for clean, efficient, and sustainable energy storage solutions drives significant advancements in materials science. This study investigates the synthesis and characterization of cadmium zinc phosphates (CdO-ZnO-P₂O₅) doped with different tungsten (CZWP) concentrations using the sol–gel method. The structural, binding energy, morphological, Brunauer–Emmett–Teller (BET) analysis, thermal, optical, and electrochemical properties were thoroughly examined. X-ray diffraction (XRD) confirmed a crystalline structure with tunable properties influenced by tungsten doping. Scanning Electron Microscopy (SEM) revealed well-ordered nanoparticles exhibiting a homogeneous distribution that was enhanced by W doping. BET reveals a moderate specific surface area, mesoporous structure, and dual-porosity characteristics, offering insights into their potential applications in photocatalysis, energy storage, and gas sensing. The TGA results indicate that tungsten doping in cadmium zinc phosphate reduces the material's coordinated water content and increases the thermal stability of the material. Optical analyses demonstrated a shift in the bandgap and an increase in optical electronegativity, highlighting the material's potential in optoelectronics. Electrochemical characterization using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) identified an optimal doping level of 2.0% W for improved charge transfer and specific capacitance, confirming its suitability for supercapacitors. Furthermore, the 2.0% W-doped electrode exhibited outstanding performance in hydrogen peroxide (H₂O₂) sensing, achieving high sensitivity, a wide linear range, and low detection limits. These findings highlight CZWP nanostructures as promising candidates for energy storage and sensing applications.