Browsing by Author "Derkaoui, Khaled"

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    MnO2 decorated Silicon Nanowires: A novel photocatalyst for improved Rhodamine B removal under visible light exposure
    (Elsevier, 2024) Derkaoui, Khaled; Bencherifa, Ismail; Hadjersi, Toufik; Belkhettab, Ilyas; Boukhouidem, K.; Bouanik, Sihem Aissiou; Brik, Afaf; Kechouane, Mohamed; Kaci, Mohamed Mehdi
    Pollution triggered by organic dyes is a prominent global concern. Thus, it is imperative to devise an effective preventative strategy to tackle this matter. Herein, using the chemical electroless deposition process, a novel SiNWs/MnO2 photocatalyst was successfully manufactured for efficacious photocatalytic purification under visible lighting. Through a series of characterization techniques, the structural, morphological, compositional, and optical features of MnO2-deposited silicon nanowires were thoroughly investigated. The photocatalytic ability of the resultant sample was reckoned by degrading Rhodamine B upon visible exposure. Following 180 min of brightness, the findings found that SiNWs/MnO2 displayed remarkable effectiveness, with a lessening of 93.4 %. The findings demonstrated a significant enhancement in degradation performance linked to the rising surface area and enhanced electron-hole segregation efficiency provided by silicon nanowires. Also, the sample's recyclability was assessed, exhibiting an encouraging sustainability with a slight fall in effectiveness (∼10%) after 6 straight utilizes. Furthermore, scavenging tests have shown that •OH and •O2− were prevalent species accountable for the RhB degradation reaction. Eventually, founded on the results, a plausible mechanism for RhB decomposition was suggested. Altogether, given the straightforward manufacturing method and impressive performance, the study argues that the novel SiNWs/MnO2 might be an intriguing photocatalyst for water contaminant remediation.
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    Ternary WO₃–MnO₂@SiNWs hybrid electrodes for high-performance Micro-supercapacitors with enhanced energy density and stability
    (Elsevier, 2025) Boukhouidem, Khadidja; Slimani, Amel; Derkaoui, Khaled; Manfo, Theodore Azemtsop; Hadjersi, Toufik; Manseri, Amar; Selmi, Noureddine; Elhak Abaidia, Seddik
    Advanced energy storage technologies, such as rechargeable Batteries and Micro-supercapacitors (μSCs) play a pivotal role in addressing the growing global energy demand. Improving their energy and power densities requires the development of electrode materials with well-engineered, hierarchical porous architectures. In this work, we report a facile hydrothermal synthesis of WO₃-MnO₂ composite nanostructures directly integrated onto silicon nanowires (SiNWs), which serve as a highly conductive and high-surface-area scaffold. The influence of annealing temperature on the structural, morphological, and electrochemical properties of the WO₃-MnO₂@SiNWs composite was systematically investigated. Structural characterization through X-ray diffraction (XRD) and surface analysis via X-ray photoelectron spectroscopy (XPS) confirmed the successful formation of the hybrid oxide network. Furthermore, scanning electron microscopy (SEM) revealed a homogeneous distribution of the nanostructured composite coating over the vertically aligned SiNWs, forming a porous, interconnected network favorable for ion diffusion. Energy-dispersive X-ray spectroscopy (EDX) mapping confirmed the uniform presence of W, Mn, O, and Si elements throughout the electrode, indicating successful and consistent deposition of the WO₃-MnO₂ layers. The optimized electrode exhibited excellent capacitive performance, delivering a specific capacitance (Csp) of 16.56 mF·cm−2, an energy density (Ed) of 0.0001 Wh·cm−2, and a power density (Pd) of 0.024 W·cm−2, along with long-term cycling stability retaining 84 % of its initial capacitance over 4000 charge–discharge cycles. Additionally, electrochemical impedance spectroscopy revealed a consistent Csp of 14.23 mF·cm−2over a wide frequency range (0.01 Hz–1 MHz), indicating efficient charge transfer and low internal resistance. A solid-state symmetric μSC device constructed using WO₃-MnO₂@SiNWs electrodes further demonstrated impressive performance, achieving a maximum specific capacitance of 96 mF·cm−2at a scan rate of 2 mV·s−1, with 85 % capacitance retention over 2300 cycles and an energy density of 0.0028 Wh·cm−2at a power density of 0.4 W·cm−2. These remarkable electrochemical properties are attributed to the synergistic effects of multivalent WO₃ and MnO₂ species combined with the high conductivity and mechanical stability of the SiNWs framework, highlighting the potential of this composite architecture for next-generation on-chip energy storage devices.