Tellurium-Based ZnO/Te/TeO2 Nanostructures for Efficient Energy Storage and Oxygen Evolution Electrocatalysis

Abstract Tellurium-derived substances have garnered considerable interest for electrochemical energy storage due to their distinctive redox properties and high electrical conductivity. TeO 2 /Te nanostructures were fabricated via oxidative ultrasonication-assisted exfoliation using hydrogen peroxide, followed by incorporation of ZnO (0–50 wt%) to create ZnO/TeO 2 /Te composites. The structural, chemical, and electrical characteristics were examined utilizing XRD, FT-IR, synchrotron-based XPS, XAS, DRS, Mott–Schottky analysis, SEM, STEM, and EDX. Electrochemical assessments in 6 M KOH exhibited pseudocapacitive characteristics. DRS and Mott–Schottky analyses indicated that the inclusion of ZnO shifts the band-edge positions and enhances interfacial charge transfer. Dunn’s examination revealed that charge retention is regulated by both capacitive and diffusion-dominated mechanisms. The enhanced composite demonstrated superior electrochemical kinetics, remarkable rate capability, and exceptional cycling stability, retaining nearly 100% capacitance after 5000 charge-discharge cycles. Oxygen evolution reaction (OER) assessments indicated an initiation potential of roughly 1.60 V relative to RHE for all specimens. The ZnO_30%@TeO 2 /Te demonstrated an overpotential of 360 mV at 10 mA/cm 2 , while ZnO_20%@TeO 2 /Te presented the lowest Tafel slope of 142 mV/dec. These results indicate that the strategic integration of ZnO improves the performance of both supercapacitors and electrocatalysts.