Manjunath Shetty

Supercritical fluid processing has developed into a versatile and environmentally responsible approach for the controlled fabrication of nanomaterials, distinguished by low density, viscosity, high diffusivity, and negligible surface tension. These intrinsic features enhance nucleation, efficient mass transport, and accurate control over particle dimensions, morphology, and compositional uniformity. This review comprehensively examines the fundamental principles of supercritical fluids, encompassing phase behavior, thermophysical characteristics, and the mechanisms governing nanoparticle formation, along with important engineering aspects related to both batch and continuous‐flow reactor configurations. The preparation of metal, metal oxide, and composite nanostructures through supercritical techniques is critically evaluated, emphasizing their benefits compared with traditional solid‐state and solution‐based synthesis routes. Special attention is given to the evolution toward high‐entropy oxides, where supercritical conditions enable homogeneous multication distribution, enhanced phase development, and defect modulation under kinetically advantageous environments. By establishing clear relationships between processing conditions, structural characteristics, and electrochemical performance, this review highlights the promise of SCF‐enabled methodologies as scalable and sustainable pathways for designing advanced multicomponent oxide materials suited for energy storage and catalytic applications.

High‐entropy oxides (HEOs) are a promising class of novel ceramic materials characterized by their complex chemistry and multifunctionality. By leveraging high configurational entropy, HEOs stabilize single‐phase structures with significant lattice distortion and tuneable electronic properties through the incorporation of multiple metal cations. This versatility makes HEOs particularly relevant for photocatalytic applications, such as dye degradation in wastewater treatment. This review explores the advancements in HEO catalysts for photocatalysis, detailing their evolution from alloys to ceramics and the thermodynamic principles that influence phase stabilization. Key distinctions between HEOs and traditional oxides are highlighted, along with the significant capabilities of HEO photocatalysts to address challenges posed by conventional systems. The article explores the crystal structure, synthesis methods, and material design for enhanced charge separation and light absorption. It compares the performance of various HEO photocatalysts and discusses their advantages over single or binary‐oxide alternatives. Finally, the review identifies critical knowledge gaps, such as the quantitative effects of entropy, and suggests future directions involving operando characterization, first‐principles modeling, and machine learning for the rapid development of next‐generation HEO materials.

This research explores the enhancement of traditional red bricks through the incorporation of red bricks and conductive polymer coatings to improve multifunctional properties while reducing production costs. Specifically, polyaniline (PANI) was applied as a conductive coating to red bricks, marking the first attempt to adapt conventional construction materials for mechanical reinforcement and energy storage applications. The improvements in mechanical strength, electrical conductivity, thermal behaviour, and energy storage capacity of the PANI‐coated bricks were investigated. Two different types of conductive polymer coating methods were used to strengthen the brick structure and improve the performance of the nanocomposites. This study also examined how PANI integration affects the density and water absorption of bricks, providing critical insight into their physical and structural behaviour. Electrochemical testing revealed that the PANI‐coated bricks functioned as efficient electrodes, exhibiting a high specific capacitance of 187 F g ⁻¹ at a scan rate of 10 mV s ⁻¹ in 1 M H ₂ SO ₄ . However, with increasing scan rates from 2 to 100 mV s ⁻¹ , the capacitance gradually decreases due to reduced ion diffusion and the inherent chemical limitations of the brick matrix. Overall, this study introduces a promising approach for transforming conventional red bricks into smart, energy storage‐active building materials.

The structural response of ceramics to extreme deformation is of significant scientific and technological relevance since such conditions are commonly encountered during both processing and service. In this study, monoclinic zirconia was subjected to high-energy ball milling for extended durations of 80 h and 120 h, followed by annealing at 1000 °C. X-ray diffraction revealed a progressive increase in the tetragonal phase content with milling duration, while subsequent annealing promoted its consolidation alongside the principal monoclinic phase, resulting in a stable biphasic structure. The phase evolution is also evaluated through a Raman spectroscopy analysis and correlated with the morphology, mechanical properties, and surface area analyses. Scanning electron microscopy confirmed the preservation of nanoscale features in the milled and annealed specimens, in contrast to the unmilled sample, which exhibited pronounced grain coarsening. The combined presence of nanostructural stability and biphasic phase constitution underscores the efficacy of high-energy ball milling, in conjunction with thermal treatment, as an effective strategy to tailor the microstructure and phase stability of zirconia ceramics for advanced engineering applications.

We report a supercritical fluid (SCF)-assisted synthesis of a tightly integrated MXene/MoS ₂ /PANI ternary heterostructure for high-performance supercapacitor applications. The SCF route enables rapid nucleation, controlled crystallization, and intimate interfacial coupling between Ti ₃ C ₂ T _x MXene and MoS ₂ nanosheets, followed by uniform in situ polymerization of polyaniline (PANI) to construct a hierarchical conductive network. This rationally engineered architecture synergistically combines electric double-layer capacitance and pseudocapacitance while minimizing charge-transfer resistance and enhancing ion transport kinetics. The optimized composite delivers a high specific capacitance of ∼325 F g ⁻¹ along with excellent cycling durability over 10,000 cycles, exhibiting progressive capacitance activation attributed to improved electrolyte accessibility and interfacial conductivity. The study introduces a time-efficient and structurally controlled strategy for fabricating MXene-based ternary heterostructures and establishes a scalable pathway toward advanced hybrid electrode materials for next-generation energy storage systems.

Flexible and high-performance supercapacitors are emerging as pivotal components in next-generation energy storage systems. In this work, a novel ternary Cu ₂ ZnSnS ₄ /MoS ₂ /CNT (CZTS/MoS ₂ /CNT) heterostructure was synthesized via a one-pot hydrothermal method and systematically evaluated for its electrochemical performance. Structural and morphological analyses (XRD, Raman, SEM, and TEM) confirmed the formation of a well-integrated heterostructure with uniform anchoring of CZTS and MoS ₂ nanoparticles on conductive CNT networks, fostering enhanced charge transport and ion diffusion. The ternary composite exhibited an impressive specific capacitance of 273.2 F g ⁻¹ at 1.25 A g ⁻¹ , significantly outperforming pristine CZTS (141.9 F g ⁻¹ ) and binary CZTS/MoS ₂ (154.8 F g ⁻¹ ). Furthermore, it demonstrated exceptional energy and power densities of 97.13 Wh kg ⁻¹ and 1.076 kW kg ⁻¹ , respectively, along with 98% capacitance retention over 1000 cycles. The superior performance arises from the synergistic interplay of MoS ₂ ’s redox-active surfaces and CNT’s high electrical conductivity, which together enhance electrochemical reversibility and mechanical robustness. This facile, scalable, and eco-friendly synthesis approach underscores the CZTS/MoS ₂ /CNT heterostructure as a promising electrode material for flexible and sustainable supercapacitor applications.

The present study investigated the tensile behavior, failure mechanisms and deformation characteristics of glass fiber-reinforced polymer (GFRP) composites with symmetric [0°/90°/90°/0°] and asymmetric [0°/90°/0°/90°] stacking sequences across a temperature range of 30–150 °C. Tensile testing revealed superior mechanical performance in the symmetric lay-up, with higher tensile strength and failure strain sustained across elevated temperatures. Failure mode analysis revealed a transition from ductile failure to brittle failure with increasing temperature, which was more pronounced in the asymmetric lay-up, along with increased delamination and reduced fiber pull-out. Failure surface examination supported these findings, revealing better interfacial bonding and matrix integrity in the symmetric lay-up. Deformation analysis further confirmed a more homogeneous distribution of strain and longer failure time in symmetric laminates. Across all the metrics, including toughness, energy absorption, and strain uniformity, the symmetric configuration outperformed the asymmetric counterpart, underscoring the critical role of balanced stacking in enhancing the thermal durability. The observed temperature-induced degradation and its impact on mechanical and failure behavior emphasize the need for temperature-sensitive design strategies in GFRP-based structures.

The exploration of innovative nanocomposite architectures in energy storage has long captivated researchers. Recent technological advancements in the development of Zinc-ion (Zn-ion) batteries have become a focal point of this research. Herein, we present the synthesis of Mn₃O₄@Titanium carbide (TCM) sheets as cathodes for the Zn-ion battery system. Various nano-characterization techniques were employed to confirm the sample characteristics and to ascertain the nanocomposites’ morphological, physical, and thermal properties. Furthermore, analyses of the electrochemical behavior of the constructed coin cells reveal their notable initial cycle capacity of approximately 675 mAh g⁻¹, underscoring the superior Zn-ion storage capacity of TCM nanostructures. The synthesized TCM nanocomposites hold promise for advancing Zn-ion battery systems, contributing to the development of safer and more cost-effective solutions for electrochemical energy storage systems.