Small Methods最新文献

TiO₂-based nanomaterials have attracted considerable attention for their ability to produce ammonia (NH₃) through photocatalysis, offering a sustainable method for nitrogen (N₂) fixation under ambient conditions. TiO₂, being a stable and benchmark semiconductor, shows great promise as a photocatalyst for utilizing light energy to show the pathway for efficient reduction of N₂ to NH₃. This review provides relevant information about the fundamental mechanisms of photocatalytic N₂ adsorption and reduction pathways, besides providing the insights essential for the development of efficient TiO₂-based photocatalysts. Various strategies, such as doping with metals and nonmetals, have been developed to modify the electronic structure of TiO₂, enabling it to absorb visible light more effectively. Furthermore, advanced strategies such as defect engineering, crystal facet modulation, and plasmonic hybrids have been extensively elucidated, demonstrating their critical role in enhancing charge carrier separation and boosting the efficiency of photocatalytic NH₃ synthesis. Moreover, the development of TiO₂-based composites by combining TiO₂ with other materials has provided promising outcomes, aiming to achieve more efficient and sustainable NH₃ production. Finally, the paper discusses the current limitations, challenges, and future perspectives in the development of high-efficiency TiO₂-based photocatalysts, experimental protocols for correct NH₃ quantification and further necessary advancements for scalable photocatalytic NH₃ production.

Applying diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to nonthermal plasma catalysis is important to gain mechanistic information to advance the electrified technology. However, conventional DRIFTS cells are often suboptimal, exhibiting unstable, non-uniform discharges and failing to replicate the plasma characteristics of practical reactors such as dielectric barrier discharge (DBD) systems. This study devises a dome-type DRIFTS flow cell that enables stable glow discharge, closely emulating the electric field distribution and flow dynamics of DBD reactors. The dome cell exhibits excellent operational stability over extended durations (>1 h) and under various plasma conditions (e.g., different excitation modes and gas switching), while delivering high-fidelity IR signals. Using the dome cell, operando DRIFTS studies of plasma catalytic CO₂ methanation under pulse excitation are conducted. The results reveal that, for a Ni/MgAlO_x catalyst, i) the surface reaction mainly follows the Langmuir–Hinshelwood mechanism with formate hydrogenation as the rate-determining step, and ii) the Eley-Rideal/Langmuir–Rideal mechanism indeed exists under plasma conditions but contributes marginally. This robust DRIFTS platform provides a reliable in situ and/or operando diagnostic tool for plasma catalytic systems, while offering mechanistic insights essential for rational catalyst/system design and optimization.

A novel procedure for preparing Ruthenium nanoparticles (RuNPs) based on low-molecular-weight amphiphilic molecules and Ru(III) complexes as antibacterial agents with controlled release properties has been developed. Two hydrophobic Ru(III) complexes, Ru-TOA and Ru-Benza, analogs to the NAMI-A prodrug, are encapsulated within the core of the micelles formed through the self-assembly of these amphiphiles. The self-assembly of amphiphile I, which contains a double polar head, results in highly water-stable and monodispersed RuNPs incorporating both hydrophobic Ru complexes. These RuNPs exhibit hydrodynamic sizes ranging from 26.7 to 104.2 nm for NPs derived from Ru-TOA complex, and ≈10 nm for those derived from Ru-Benza. Compared to Ru(III) complexes, these RuNPs offer several advantages, including protection from aqueous degradation and enhanced bacterial uptake. Moreover, post-synthesis modification of the RuNPs with molecular staples based on polyethylene glycol chains of varying lengths enables controlled Ru release, reducing the burst effect. Interestingly, these RuNPs demonstrate excellent antibacterial activity, with minimum inhibitory concentration (MIC) values of 16 mg·L⁻¹ and minimum bactericidal concentration (MBC) values of 32 mg·L⁻¹ against a broad range of Gram-positive bacteria, including S. aureus, Staphylococus pseudintermedius, and Enterococcus faecalis, highlighting their potential efficacy against clinically relevant bacterial strains.

Ion-conducting gels are indispensable for bioelectronics, offering softness, high ionic conductivity, and biocompatibility. Nevertheless, sustaining robust performance under physiological conditions demands moving beyond isolated material or device innovations to a unified, multiscale design approach. At the material level, advances in polymer network engineering enable precise tuning of ion mobility, retention, and electrochemical stability, while simultaneously imparting mechanical toughness, hydration preservation, and self-healing. At the device level, these gels are tailored for seamless electrode integration, ensuring high signal fidelity, low impedance, and stable ionic-electronic coupling under deformation. When integrated into closed-loop architectures encompassing biosignal acquisition, signal processing, and feedback control, ion-conducting gels evolve from passive conductors into active, reconfigurable elements within autonomous diagnostic and therapeutic systems. This review highlights the critical interplay of material design, device integration, and system-level engineering in advancing long-lived, sustainable bioelectronic technologies.

Green hydrogen production suffers from the intermittent nature of renewable energy resources, which accelerates the degradation of electrocatalysts in water electrolyzers. Therefore, it is crucial to minimize the catalyst degradation under dynamic operating conditions. This study investigated the degradation behavior of an oxygen evolution reaction catalyst under two types of dynamic operation via controlling the voltage range, elapsed time at high voltage, and power fluctuation frequency. High-voltage operation and short start/stop periods caused severe catalyst degradation. In addition, chemical and physical characterization identified the formation of amorphous Co(OH)₂ and defects as key factors in Co₃O₄ degradation. These results indicated that it is possible to respond to dynamic operation by understanding how the degradation phenomenon is intensified by dynamic operating conditions. In addition, a thermal-healing method is investigated for degraded catalysts, which restores defects by inducing atomic rearrangement toward the original crystal structure, returning the Co₃O₄ catalyst to its initial performance. The results indicated that a suitable restoration strategy targeting the origin of the catalyst degradation can lead to the realization of a water electrolyzer capable of long-term operation.

Poor mass transfer of reactants at the catalytic interface seriously impedes solar-driven CO₂ conversion, particularly for photocatalysis in pure water without sacrificial reagents, which is detrimental to tackling energy shortages and achieving carbon neutrality. Herein, a hollow porous BiVO₄@O-TiN-TiO₂ nanoantenna arrays (NAs) heterojunction photocatalyst with a photothermal effect is developed for efficient photocatalytic CO₂ methanation. The hollow porous array structure formed after annealing in ammonia and air significantly increases the photocatalysts’ specific surface area and surface temperature, enhancing light absorption, CO₂ molecule mass transfer, and activation on the catalyst surfaces. Benefiting from the collaborative matching of energy and reactants at the catalytic interface, the yields of CO and CH₄ over the hollow porous BiVO₄@O-TiN-TiO₂ NAs photocatalyst reached 175.8 and 373.8 µmol m⁻² h⁻¹ (89.5% selectivity) in pure water, which are 1.3 and 21.1 folds higher than that of the BiVO₄@TiO₂ NAs photocatalyst, respectively. Notably, the low-cost BiVO₄@O-TiN-TiO₂ NAs photocatalyst achieves a solar-to-fuels efficiency of 0.6‰, comparable to catalytic systems using noble metals or sacrificial agents. This work demonstrates the highly selective conversion of CO₂ to CH₄ via enhanced reactant mass transfer and multi-field (photo-electric-thermal) coupling, offering a potential approach for solar-driven low-cost synthesis of hydrocarbon fuels.

X-ray detection is crucial for medical imaging and industrial non-destructive testing. However, conventional materials face limitations such as low absorption efficiency, high dark current, and the necessity for external power bias. This study presents a novel inorganic polar oxide crystal, Cs₂TeMo₃O₁₂, as a high-performance direct-conversion X-ray detector material, particularly for self-powered applications. The stereochemically active lone-pair electrons of Te⁴⁺ induce a non-centrosymmetric polar structure, which generates a built-in electric field that enables efficient charge carrier separation under zero bias. Along the polar Z-direction, the crystal exhibits a high resistivity of 5.08 × 10¹⁴ Ω cm, a considerable mobility-lifetime product of 1.08 × 10^‒3 cm² V^‒1, and an excellent sensitivity of 436 µC Gy_air ^‒1 cm^‒2 under a 2000 V cm^-1 electric field. Most notably, the device operates effectively in a self-powered mode, achieving a sensitivity of 178 µC Gy_air ^‒1 cm^‒2 and an ultralow detection limit of 10.5 nGy_air s^‒1. Furthermore, it demonstrates exceptional operational stability with negligible dark current drift. This work not only introduces Cs₂TeMo₃O₁₂ as an exceptional candidate for low-dose and self-powered X-ray detection but also provides a novel design strategy leveraging lone-pair electrons for developing advanced photoelectric materials.

Despite their low power consumption, commercial black-and-white reflective displays based on electrophoretic technology (i.e., electronic paper) suffer from limited brightness, contrast, and temperature tolerance. Here, this study presents an electrochemical display mechanism that addresses these limitations by integrating a light-scattering layer beneath a roughened indium tin oxide (ITO) electrode supporting reversible metal electrodeposition (RME). The scattering layer is composed of an interwoven titanium dioxide nanowire (TiO₂ NW) network, which provides efficient broadband light scattering to produce a white appearance, while simultaneously ensuring mechanical durability and ion transport. In contrast, a black state is achieved via copper electrodeposition onto the roughened ITO, where the resulting morphology induces strong broadband light absorption. The device exhibits brightness and contrast ratios exceeding those of current commercial e-readers by more than two-fold, along with stable switching across a wide temperature range (−5 °C to 55 °C). These results demonstrate a scalable electrochemical nanophotonic platform for next-generation black-and-white reflective displays.

Water eutrophication driven by nitrates (NO₃⁻), phosphates (PO₄³⁻), and ammonium salts (NH₄⁺), along with groundwater contamination caused by fluorides (F⁻) and bromides (Br⁻), collectively poses significant threats to both ecological systems and human health. Capacitive Deionization (CDI) has demonstrated significant potential for selectively removing these pollutants due to its low energy consumption, absence of chemical byproducts, and cost-effectiveness. However, systematic mechanistic analyses and material design strategies focusing on this specific area remain insufficient. To this end, against the backdrop of water eutrophication and groundwater contamination, this paper presents a relatively comprehensive review of the research progress regarding the removal of NO₃⁻, PO₄³⁻, NH₄⁺, F⁻, and Br⁻ using CDI technology. The review first discusses the advantages and limitations of conventional methods for removing these pollutants. It elaborates on the ion storage mechanism of CDI and addresses its fouling mechanisms and mitigation strategies. Subsequently, for different ions, the review systematically sorts out various types of electrode materials and explains in detail the intrinsic mechanisms through which they achieve ion selectivity. Finally, the review discusses current challenges in CDI technology, such as ion selectivity, electrode fouling, complexity of real water matrices, cost, and long-term stability, and proposes specific future research directions.

Large quantities of sulfur amass annually as waste material produced in the desulfurization of crude oil. Commonly applied in rubber vulcanization, sulfur can covalently crosslink polymer chains to improve the material properties. Herein, the concept of ionic vulcanization is introduced – ionotropic gelation of sodium polysulfides with alcohol moieties and bridging calcium ions, exemplified using cellulose nanocrystals, introduces ionic sulfur crosslinked areas of hydrophobicity to a bio-based hydrogel. These crosslinks can be broken at will in an aqueous environment. It is demonstrated that ionic vulcanization increases the storage modulus of the calcium gelled CNC by up to 888%, and the swelling percentage by 235%. This swelling ratio increase translates to improved moisture sorption, with 98 wt.% water captured from the atmosphere, proving the potential application of ionically vulcanized materials for water harvesting. Ionic vulcanization is therefore proposed as a method to reversibly generate functional gel materials with improved properties that utilize waste and bio-based components.