Zn-ZnO(Nw)-rGO hybrid electrodes for supercapacitor applications were successfully prepared in situ by a one-step microwave-assisted hydrothermal method by deposition of reduced graphene oxide (rGO) on the structure of ZnO nanowires grown on the Zn foil. During the hydrothermal treatment, two processes occur the reduction of graphene oxide (GO) and the deposition of rGO on the Zn-ZnO(Nw) support. The growth of ZnO nanowires was achieved by thermal oxidation below the melting point of the Zn foil in a controlled atmosphere. The as-obtained electrodes were assessed for structural, optical, and morphological properties by X-ray diffraction, Raman spectroscopy, ultraviolet-visible spectroscopy, SEM microscopy, and EDX analysis. The supercapacitor properties of the Zn-ZnO(Nw)-rGO hybrid electrodes were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge analysis. The CV curve reveals that the Zn-ZnO(Nw)-rGO hybrid structures work as negative electrodes and exhibit a non-ideal rectangle-like shape, suggesting that the as-synthesized structure behaves as a pseudo-capacitor. A maximum capacitance was determined to be 395.79 mF cm⁻² at a scan rate of 5 mV s⁻¹. Based on GCD analysis, the maximum specific capacitance of 145.59 mF cm⁻² was achieved at a low power density of 2 mA cm⁻². The cycle life assessment of the Zn-ZnO(Nw)-rGO hybrid electrode over a 250-cycle number was performed by CV and GCD analysis. The maximum retention rate of 120.86% was achieved from GCD analysis over 250 cycles for the Zn-ZnO(Nw)-rGO hybrid electrode.

This study investigated the application of an advanced electrooxidation process with three-dimensional tin oxide deposited onto a titanium plate anode, named 3-D Ti/SnO₂, for the degradation and mineralization of one of the most important emerging contaminants with cytostatic properties, doxorubicin (DOX). The anode was synthesized using a commercial Ti plate, with corrosion control in acidic medium, used as a substrate for SnO₂ deposition by the spin-coating method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses revealed that porous SnO₂ was obtained, and the rutile phase of TiO₂ was identified as an intermediary substrate onto the Ti plate. The results of CV analysis allowed us to determine the optimal operating conditions for the electrooxidation process conducted under a constant potential regime, controlled by the electron transfer or the diffusion mechanisms, involving hydroxyl radicals. The determination of UV–VIS spectra, total organic carbon (TOC), and chemical oxygen demand (COD) allowed us to identify the degradation mechanism and pathway of DOX onto the 3-D Ti/SnO₂ anode. The effective degradation and mineralization of DOX contained in water by the electrooxidation process with this new 3-D dimensionally stable anode (DSA) was demonstrated in this study.

Titanium/TiO₂ mesoporous/reduced graphene oxide structure for construction of a hybrid electrode was successfully developed using a facile and effective spin-coating technique. The as-prepared structures were characterized using ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, RAMAN analysis, scanning electron microscopy (SEM) coupled with elemental analysis (EDX), and atomic force microscopy (AFM). In addition, the electrochemical behavior was assessed by cyclic voltammetry (CV) in a 1M KNO₃ supporting electrolyte and in the presence of 4 mM K₃Fe(CN)₆ to determine the electroactive surface area and apparent diffusion coefficient of the hybrid electrode. The charge transfer resistance was investigated via electrochemical impedance spectroscopy (EIS) in a 0.1 M Na₂SO₄ supporting electrolyte to confirm the role of reduced graphene oxide on the electrode’s surface. The potential application of as-obtained hybrid electrodes in electroanalysis was tested through cyclic voltammetry in the presence of doxorubicin as the target analyte, in the concentration range between 1 to 7 mg L⁻¹ DOX. By using mesoporous TiO₂ with a high specific surface area (~140 m² g⁻¹) in the synthesis of the composite material based on a Ti/TiO₂(Ms)/rGO hybrid structure, was obtained a 2.3-times increase in electroactive surface area than the geometrical surface area of the hybrid electrode. These results provide new insights into the development of high-performance and cost-effective electrochemical sensors based on reduced graphene oxide films on metallic structures for applications in the detection processes of drugs from wastewater.