A key challenge in the development of sustainable water-splitting (WS) systems is the formulation of electrodes by efficient combinations of electrocatalyst and binder materials. Cellulose, a biopolymer, can be considered an excellent dispersing agent and binder that can replace high-cost synthetic polymers to construct low-cost electrodes. Herein, a novel electrocatalyst was fabricated by combining Fe₂O₃ and Ni on microcrystalline cellulose (MCC) without the use of any additional binder. Structural characterization techniques confirmed the formation of the Fe₂O₃–Ni nanocomposite. Microstructural studies confirmed the homogeneity of the ~50 nm-sized Fe₂O₃–Ni on MCC. The WS performance, which involves the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), was evaluated using a 1 M KOH electrolyte solution. The Fe₂O₃–Ni nanocomposite on MCC displayed an efficient performance toward lowering the overpotential in both the HER (163 mV @ 10 mA cm⁻²) and OER (360 mV @ 10 mA cm⁻²). These results demonstrate that MCC facilitated the cohesive binding of electrocatalyst materials and attachment to the substrate surface. In the future, modified cellulose-based structures (such as functionalized gels and those dissolved in various media) can be used as efficient binder materials and alternative options for preparing electrodes for WS applications.

This work explores the role of cetyltrimethylammonium bromide (CTAB) as a morphology-directing agent in the hydrothermal synthesis of NiFe₂O₄ electrodes for high-performance supercapacitor applications. By fine-tuning CTAB concentrations (0.5%, 1%, and 1.5%), a tunable nanosheet morphology was achieved, with the NiFe-1 sample exhibiting uniformly interconnected nanosheets that enhanced ion diffusion, charge transport, and surface redox activity. Structural and surface analyses confirmed the formation of single-phase cubic NiFe₂O₄ and the presence of Ni²⁺ and Fe³⁺ oxidation states. Electrochemical characterization in a 2 M KOH electrolyte revealed that the NiFe-1 electrode achieved an areal capacitance of 8.21 F/cm² at 20 mA/cm², with an energy density of 0.34 mWh/cm² and a power density of 5.5 mW/cm². The electrode retained 79.61% of its capacitance after 10,000 cycles, demonstrating excellent stability. An asymmetric pouch-type supercapacitor device (APSD), assembled using NiFe-1 and activated carbon, exhibited an areal capacitance of 1.215 F/cm² and delivered an energy density of 0.285 mWh/cm² at a power density of 6.5 mW/cm² across a wide 0–1.8 V voltage window. These results confirm that CTAB-assisted nanostructuring significantly improves the electrochemical performance of NiFe₂O₄ electrodes, offering a scalable and effective approach for next-generation energy storage applications.

Designing advanced electrode architectures with tailored morphology and redox synergy is essential for achieving high-performance supercapacitive energy storage. In this study, a PVP-assisted hydrothermal approach was employed to synthesize binder-free NiCo₂O₄ nanostructured electrodes directly on nickel foam substrates. By modulating the PVP concentration (0.5–2 wt%), hierarchical flower-like nanosheets were engineered, with the NiCo-P₁ sample (1 wt% PVP) exhibiting an optimized structure, superior electroactive surface area, and enhanced ion accessibility. Comprehensive electrochemical analysis revealed that NiCo-P₁ delivered an outstanding areal capacitance of 36.5 F/cm² at 10 mA/cm², along with excellent cycling stability over 15,000 cycles with 80.97% retention. Kinetic studies confirmed dominant diffusion-controlled redox behavior with high OH⁻ diffusion coefficients and minimal polarization. An asymmetric pouch-type supercapacitor device (NiCo-P₁//AC) exhibited a wide operating window of 1.5 V, achieving a remarkable areal capacitance of 187 mF/cm², energy density of 0.058 mWh/cm², and capacitive retention of 78.78% after 5000 cycles. The superior performance is attributed to the synergistic integration of mixed-valence Ni and Co species, engineered nanosheet morphology, and low interfacial resistance. This work underscores the significance of surfactant-directed design in advancing cost-effective, high-performance electrodes for next-generation flexible energy storage technologies.

Addressing the global energy demand requires the development of sustainable and highly efficient technologies for clean energy generation. One of the primary challenges in the oxygen evolution reaction (OER) is overcoming sluggish reaction kinetics, which requires the design of electrocatalysts with greater activity and long-term stability. In this study, a precipitation method was employed to synthesize polyethylene glycol (PEG) assisted tungsten oxide (WO₃) as an effective and stable electrocatalyst for OER. PEG was incorporated at varying concentrations (1%, 3%, and 5%) to modulate the structural and electrochemical characteristics of WO₃. Among the resulting composites, the sample with 3% PEG (PEG-WO₃-2) exhibited the most favorable catalytic behavior, achieving a low overpotential of 407.7 mV at a current density of 10 mA cm⁻² and a Tafel slope of 76.2 mV dec⁻¹ in 1 M KOH electrolyte. Furthermore, long-term electrochemical stability was evaluated over 5000 consecutive cycles, revealing minimal degradation in catalytic activity. The heightened performance is attributed to the optimized composition, improved electron transport properties, and the presence of a higher density of active sites, all of which contribute to the superior catalytic activity of the PEG-WO₃-2 electrocatalyst.

The development of environmentally friendly technology is vital to effectively address the issues related to environmental deterioration. This work integrates ZnO-decorated MoS₂ (MZ) to create a high-performing PVDF-based PVDF/MoS₂-ZnO (PMZ) hybrid polymer composite film for sonocatalytic organic pollutant degradation. An efficient synergistic combination of MZ was identified by altering the ratio, and its influence on PVDF was assessed using diverse structural, morphological, and sonocatalytic performances. The PMZ film demonstrated very effective sonocatalytic characteristics by degrading rhodamine B (RhB) dye with a degradation efficiency of 97.23%, whereas PVDF only degraded 17.7%. Combining MoS₂ and ZnO reduces electron–hole recombination and increases the sonocatalytic degradation performance. Moreover, an ideal piezoelectric PVDF polymer with MZ enhances polarization to improve redox processes and dye degradation, ultimately increasing the degradation efficiency. The degradation efficiency of RhB was seen to decrease while employing isopropanol (IPA) and p-benzoquinone (BQ) due to the presence of reactive oxygen species. This suggests that the active species •O₂⁻ and •OH are primarily responsible for the degradation of RhB utilizing PMZ2 film. The PMZ film exhibited improved reusability without substantially decreasing its catalytic activity. The superior embellishment of ZnO onto MoS₂ and effective integration of MZ into the PVDF polymer film results in improved degrading performance.

In this work, we report a facile and tunable electrodeposition approach for engineering polyacrylic acid (PAA)-modified Co₃O₄ electrodes on nickel foam for high-performance asymmetric pouch-type supercapacitors. By systematically varying the PAA concentration (0.5 wt %, 1 wt %, and 1.5 wt %), we demonstrate that the CO-1 sample (1 wt % PAA) exhibited the most optimized structure and electrochemical behavior. The CO-1 electrode delivered a remarkable areal capacitance of 3467 mF/cm² at 30 mA/cm², attributed to its interconnected nanosheet morphology, enhanced ion diffusion, and reversible Co²⁺/Co³⁺/Co⁴⁺ redox transitions. Electrochemical impedance spectroscopy confirmed low internal resistance (0.4267 Ω), while kinetic analysis revealed a dominant diffusion-controlled charge storage contribution of 91.7%. To evaluate practical applicability, an asymmetric pouch-type supercapacitor device was assembled using CO-1 as the positive electrode and activated carbon as the negative electrode. The device operated efficiently within a 1.6 V window, achieving an impressive areal capacitance of 157 mF/cm², an energy density of 0.056 mWh/cm², a power density of 1.9 mW/cm², and excellent cycling stability. This study underscores the critical role of polymer-assisted growth in tailoring electrode architecture and provides a promising route for integrating cost-effective and scalable supercapacitor devices into next-generation energy storage technologies.