ABSTRACT Hexavalent chromium [Cr(VI)] is a serious environmental problem that needs to be removed efficiently from water without the need for reagents. A two‐step hydrothermal/solvothermal method was employed to synthesize a ternary piezocatalyst of carbon quantum dots (CDs) coupled with Mn 0.5 Cd 0.5 S (MCS) and BiOBr (BOB), denoted MBC, with an interfacial Bi─S bond and tested for the piezocatalytic reduction of Cr(VI) under dark and ultrasound‐assisted conditions. BOB microsphere architecture which was also uniformly decorated with cauliflower‐like MCS aggregates and had a systematic increase in carbon content from 12.5 to 25.9 wt.% as the nominal loading of CDs in the BOB was increased from MBC‐1 to MBC‐3. In the case of Cr(VI), all three ternary MBC composites showed significant removal efficiency of the target ion compared to the respective BOB and MCS, with MBC‐2 showing the best removal efficiency (89%), whereas the control without the catalyst removed 5.2% of the Cr(VI), which indicates that the removal of Cr(VI) is not a sonolytic effect but a true piezo‐driven effect. Based on these results, an S‐scheme charge‐transfer mechanism that involves the interface between chemically bonded Bi─S and anchored CDs is proposed.
ABSTRACT Tailoring the electrode–electrolyte combination is an important strategy for improving the charge storage kinetics of supercapacitive devices. Here, the effect of aqueous electrolytes (3 m KOH, H 2 SO 4 , Na 2 SO 4 ) on the electrochemical response of Indian loofah‐derived activated carbon (AC) prepared via controlled carbonization and NaOH‐assisted hydrothermal activation is examined. The electrodes exhibit high specific capacitance (at 1 mV s −1 ) of 362.28 F g −1 in H 2 SO 4 and 336 F g −1 in KOH, decreasing significantly to 147.81 F g −1 in Na 2 SO 4 . Additionally, it demonstrates an excellent capacity retention of 98% (10 000 cycles), a wide voltage (≈1.1 V) window and delivers an energy density of 38.08 Wh kg −1 at 549.99 W kg −1 in 3 m KOH compared to others. It is attributed to the ionic mobility, hydration radius, conductivity, and interactions of the electrolytic ions with surface functional groups of AC. Besides, symmetric AC cells using a 3 m KOH aqueous solution outperform their solid‐state counterparts (3 m KOH + Polyvinyl Alcohol), delivering 215 F g −1 (at 1 mV s −1 ) and 20.93 Wh kg −1 (at 500 W kg −1 ). These findings provide key insights into optimizing electrode‐electrolyte synergy for high‐performance energy storage systems.
ABSTRACT No single imaging modality currently achieves the combined requirements of high spatial resolution, molecular sensitivity, and deep tissue penetration. Dual contrast agents offer a better strategy to overcome these limitations by integrating complementary signal mechanisms within a single platform. Here, we establish a structure–property–performance framework that connects material design with imaging output and biological behavior across major modality pairings, including MRI–optical (Magnetic Resonance Imaging), MRI‐PET/SPECT (Magnetic Resonance Imaging‐ F and single photon emission computed tomography), and CT‐optical (Computed Tomography‐Optical) systems. We identify key governing constraints such as signal interference, sensitivity mismatch, and size‐dependent pharmacokinetics and show how these emerge from nanoscale design and surface chemistry. Despite significant progress, translation remains hindered by limited predictability, safety concerns, and manufacturing complexity. This review highlights that quantitatively driven, integrative design strategies are essential to transform dual contrast agents from experimental constructs into clinically reliable tools.
ABSTRACT Molybdenum trioxide (MoO 3 ) has emerged as a promising cathode material for aqueous zinc‐ion batteries (AZIBs) owing to its high theoretical capacity and distinctive layered structure. Nevertheless, its practical implementation in energy storage devices is constrained by limited electrochemical activity and sluggish Zn 2+ ion diffusion kinetics. Overcoming these challenges is essential for realizing the full potential of MoO 3 ‐based electrodes in high‐performance AZIBs. This study proposes an anionic sulfur doping strategy to modulate the covalency of chemical bonds around Mo sites in MoO 3 nanobelts, thereby substantially enhancing their charge storage capacity. Sulfur doping not only introduces low‐valence Mo sites, improving the electronic conductivity of the material, but also provides additional ion storage sites. The aqueous zinc‐ion battery (S‐MoO 3‐ x //Zn) constructed with the optimized S‐doped MoO 3‐ x (named as S‐MoO 3‐ x ) as the cathode and commercial zinc foil as the anode delivers a high specific capacity of 254 mAh g −1 at a current density of 1 A g −1 , along with excellent cycling stability, retaining 65.3% of its capacity after 500 cycles, outperforming other recently reported aqueous zinc‐ion battery systems. This work provides a valuable reference and motivation for the further development of molybdenum‐based and other layered materials in high‐performance aqueous zinc‐ion batteries.
ABSTRACT Semiconductor nanomembranes offer a scalable platform for integrating layered topological insulators onto arbitrary host substrates. The integration of topological insulator and nanomembrane technologies, such as silicon‐on‐insulator (SOI), remains underexplored, despite the importance of these materials for building flexible quantum devices. This work reports the growth, fabrication, and structural characterization of freestanding Bi 2 Te 3 /Si(111) heterostructure membranes. 50 nm‐thick Bi 2 Te 3 layers were epitaxially grown by molecular beam epitaxy (MBE) on commercial silicon‐on‐insulator SOI(111) substrates. Using a spin‐coating nail‐polish layer over the Bi 2 Te 3 surface to protect it during the fabrication process, a sacrificial layer (buried oxide layer) was selective wet‐etched using a hydrofluoric acid solution. Post‐transfer, high‐resolution x‐ray diffraction measurements confirm that the transfer process preserves the high crystalline quality of the Bi 2 Te 3 layer. Finally, scanning tunneling microscopy indicates well‐defined terraces, demonstrating that the transfer procedure preserves the surface morphology, while scanning tunneling spectroscopy shows band gap values along the surface of the transferred Bi 2 Te 3 layer in good agreement with values expected for Bi 2 Te 3 semiconductor material. Our results point towards integration between topological insulators and already established technological platforms based on silicon membranes.
