The need to minimize carbon emissions and improve sustainable energy systems has stimulated significant research into multifunctional materials. This work presents a unique MXene@MOF and sodium alginate hydrogel composite as an electrocatalyst in energy storage and conversion. The Max-phase titanium niobium aluminum carbide (TiNbAlC) was etched to remove Al layers, producing MXene (TiNbCTx). The MXene nanosheets were dispersed in methanol, ultrasonicated, and mixed with polyvinylpyrrolidone (PVP). Subsequently, Zn(NO₃)₂·6H₂O and Co(NO₃)₂·6H₂O were added, followed by 2-methylimidazole, and stirred for 2 h. After 4 h, centrifugation, washing, and freeze-drying produced TiNbC@MOF. This composite was further incorporated into a sodium alginate hydrogel to construct TiNbC/MOF@SA-H. Besides, the characterization included SEM, EDX, XRD, FTIR, AFM, TGA, and XPS analysis. The performance of the electrocatalyst was assessed for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in an alkaline medium (1 M KOH). TiNbC/MOF@SA-H demonstrated excellent capacitance, high rate capability, and stability over 1000 cycles. TiNbC/MOF@SA-H demonstrates enhanced OER electrocatalytic performance relative to the reference IrO₂ and the composite TiNbC/MOF, exhibiting low overpotentials of 185, 188 and 204 mV at current densities of 10, 20 and 50 mA cm⁻², respectively. Additionally, it shows superior HER catalytic activity compared to other prepared samples, requiring only 17, 79 and 325 mV to achieve current densities of 10, 50 and 100 mA cm⁻², respectively. The material achieved an OER Tafel slope of 84 mV dec⁻¹ and a HER Tafel slope of 61.8 mV dec⁻¹ at a 1 V s⁻¹ scan rate.

The corrosion behavior of aluminum 1060 in hydrated salt phase change materials (PCM) melts comprised of Na₂HPO₄·12H₂O - Na₂SO₄·10H₂O was investigated through electrochemical tests as a function of pH. The pH of PCM medium was adjusted by adding H₂SO₄or NaOH. Electrochemical impedance spectroscopy reveals the existence of concentration difference layer at aluminum/PCM interface ascribed to the adsorption of PCM species and the formation of aluminum oxides. The observed anodic branch of DC polarization exhibits potential independence which is ascribed to the formation of surface oxide film and the accumulation of hydrogen molecules inside surface pores. The oxide film formed at neutral condition is characterized as the most compact and corrosion resistant while as the environmental pH shifts away from 7 the oxides/aluminum dissolution is accelerated and more aluminum 1060 substrate is exposed.

Developing high-performance biocathodes remain one of the most challenging aspects of the microbial electrosynthesis (MES) system and the primary factor limiting its output. Herein, a hollow porous carbon (PC) fabricated with MXenes coated over an electrode was developed for MES systems to facilitate the direct delivery of CO₂ to microorganisms colonized. The result highlighted that MXene@PC (Ti₃C₂T_x@PC) has a surface area of 434 m²/g. The Ti₃C₂T_x@PC MES cycle shows that in cycle 4 and cycle 5, the values are -309.2 and -352.3. Cyclic voltammetry showed that the coated electrode current response (mA) increased from -4.5 to -20.2. The substantial redox peaks of Ti₃C₂T_x@PC biofilms are displayed at -741, -516, and -427 mV vs Ag/AgCl, suggesting an enhanced electron transfer owing to the Ti₃C₂T_x@PC complex coating. Additionally, more active sites enhanced mass transfer and microbial development, resulting in a 46% rise in butyrate compared to the uncoated control. These findings demonstrate the value of PC modification as a method for MES-based product selection.

Salt hydrates (MgSO₄ and ZnSO₄) impregnated in zeolites, offer a variety of improvements, mostly providing a large surface area for salt hydrates and water molecules. A composite of 5 and 10% of salt contents were prepared as heat storage materials. The study’s finding showed that dehydration enthalpy of MgSO₄ (1817 J g⁻¹) and ZnSO₄ (1586 J g⁻¹) were 10 and 15% improved than pure salt hydrates by making composites. During the hydration process of composites, the water sorption is 30–37% improved and further the increasing of salt contents in composites enhances more 10% increase in the water resorption. The cyclicability of MgSO₄/zeolite and ZnSO₄/zeolite were 45 and 51% improved than their corresponding pure salt hydrates. The effect of humidity on the water sorption result reveals that composites of MgSO₄/zeolite and ZnSO₄/zeolite at 75% relative humidity (RH), the mass of water are 51 and 40% increase than 55% RH.