Search Results (181)

With the rapid growth of energy demand, the development of efficient energy-conversion technologies (e.g., water splitting, fuel cells, metal-air batteries, etc.) becomes an important way to circumvent the problems of fossil fuel depletion and environmental pollution, which motivates the pursuit of high-performance electrocatalysts with controllable compositions and morphologies. Among them, two-dimensional (2D) Pt-group metallic electrocatalysts show a series of distinctive architectural merits, including a high surface-to-volume ratio, numerous unsaturated metal atoms, an ameliorative electronic structure, and abundant electron/ion transfers channels, thus holding great potential in realizing good selectivity, rapid kinetics, and high efficiency for various energy-conversion devices. Considering that great progress on this topic has been made in recent years, here we present a panoramic review of recent advancements in 2D Pt-group metallic nanocrystals, which covers diverse synthetic methods, structural analysis, and their applications as electrode catalysts for various energy-conversion technologies. At the end, the paper also outlines the research challenges and future opportunities in this emerging area. Full article

The sludge pyrolysis technology for biochar production delivers dual environmental benefits, addressing both sludge disposal challenges and enabling environmental remediation through the utilization of the resultant biochar. However, the complex multi-step procedures and low catalyst output in previous studies constrain the practical implementation of this technology. A facile sludge pyrolysis method was constructed to achieve the batch production of municipal sludge biochar (MSB) in this study. Compared to municipal sludge (MS), the resultant MSB showed a higher BET surface area, more well-developed pore channel architecture, and plentiful active sites for activating peroxymonosulfate (PMS). Under the optimized conditions (C_MSB = C_PMS = 0.2 g/L), 93.34% of Acid Red G (ARG, 20 mg/L) was degraded after 10 min, posing an excellent rate constant of 0.278 min⁻¹. Additionally, MSB demonstrated excellent broad pH adaptability, ion interference resistance, reusability, and recyclability for ARG elimination. It was primary Fe sites that excited PMS to generate ${\mathrm{O}}_2^{•-}$ and Fe-oxo species (Fe^IV=O) for ARG degradation. The reaction process exhibited minimal heavy metal leaching, indicating limited environmental risk. Therefore, the practical applicability of the sludge biochar production, coupled with its scalable manufacturing capacity and exceptional catalytic activity, collectively demonstrated that this study established a viable pyrolysis methodology for municipal sludge, offering critical insights for sludge disposal and resource reutilization. Full article

Compared to pure SF₆ gas, the SF₆/CF₄ gas mixture exhibits certain advantages in reducing greenhouse effects, lowering the liquefaction temperature, and decreasing the sensitivity to non-uniform electric fields, demonstrating significant application potential in high-voltage electrical equipment. This study employs a two-dimensional plasma fluid model to investigate the partial discharge phenomena induced by free metallic particles in SF₆/CF₄ gas mixtures, analyzing the spatiotemporal evolution characteristics of key parameters, such as the charged particle density and axial electric field, under different mixing ratios. The simulation results show that there are two kinds of positive stream discharge phenomena, “continuous and decaying”, when the gas mixture ratio is 90%CF₄-10%SF₆ and 40%CF₄-60%SF₆. The proportion of CF₄ in the gas mixture will affect the spatial distribution of charged particles and the production and disappearance of electrons. When the proportion of CF₄ is 90%, the content of positive ions in the discharge channel is the highest, and the electric field formed by the positive space charge of CF₄⁺ in the stream head promotes the continuous propagation of the stream. As the concentration of CF₄ decreases, the main ionization reaction at the stream head shifts from CF₄ to SF₆, and a negative space charge region dominated by SF₆⁻ particles is also formed near the stream head, changing the electric field distribution near the flow head. The adhesion reaction rate is greater than the ionization reaction rate, resulting in the disappearance of electrons greater than the production, and the stream phenomenon tends to decay. These simulation results are helpful to understand the dynamic process of positive stream discharge induced by free metal particles in SF₆/CF₄ gas mixtures, and they provide a theoretical basis for better solutions to equipment damage caused by partial discharge. Full article

The bioavailability of heavy metals is profoundly influenced by their interactions with active soil components (microorganisms, organic matter, and iron minerals). However, the effects of urease-producing bacteria combined with organo-Fe hydroxide coprecipitates (OFCs) on Cd accumulation in wheat, as well as the mechanisms underlying these effects, remain unclear. In this study, pot experiments integrated with high-throughput sequencing were employed to investigate the impacts of the urease-producing bacterial strain TJ6, ferrihydrite (Fh), and OFCs on Cd enrichment in wheat grains, alongside the underlying soil–microbial mechanisms. The results demonstrate that the strain TJ6-Fh/OFC consortium significantly (p < 0.05) reduced (50.1–66.7%) the bioavailable Cd content in rhizosphere soil while increasing residual Cd fractions, thereby decreasing (77.4%) Cd accumulation in grains. The combined amendments elevated rhizosphere pH (7.35), iron oxide content, and electrical conductivity while reducing (14.5–21.1%) dissolved organic carbon levels. These changes enhanced soil-colloid-mediated Cd immobilization and reduced Cd mobility. Notably, the NH₄⁺ content and NH₄⁺/NO₃⁻ ratio were significantly (p < 0.05) increased, attributed to the ureolytic activity of TJ6, which concurrently alkalinized the soil and inhibited Cd uptake via competitive ion channel interactions. Furthermore, the relative abundance of functional bacterial taxa (Proteobacteria, Gemmatimonadota, Enterobacter, Rhodanobacter, Massilia, Nocardioides, and Arthrobacter) was markedly increased in the rhizosphere soil. These microbes exhibited enhanced abilities to produce extracellular polymeric substances, induce phosphate precipitation, facilitate biosorption, and promote nutrient (C/N) cycling, synergizing with the amendments to immobilize Cd. This study for the first time analyzed the effect and soil science mechanism of urease-producing bacteria combined with OFCs in blocking wheat’s absorption of Cd. Moreover, this study provides foundational insights and a practical framework for the remediation of Cd-contaminated wheat fields through microbial–organic–mineral collaborative strategies. Full article

The formation of unstable solid electrolyte interphases (SEIs) on the surface of lithium metal anodes poses a significant barrier to the commercialization of lithium metal batteries (LMBs). Rational modulation of solvation structures within the electrolytes emerged as one of the most effective strategies to enhance interfacial stability in LMBs; however, this approach often compromises the structural stability of the bulk electrolyte. Herein, we present an innovative method that improves interface stability without adversely affecting the bulk electrolyte’s structural stability. By employing ZSM molecular sieves as efficient ion channels on the lithium metal anode surface—termed ZSM electrolytes—a more aggregated solvation structure is induced at the lithium metal interface, resulting in an anion-rich interphase. This anion-enriched environment promotes the formation of an SEI derived from anions, thereby enhancing the stability of the lithium metal interface. Consequently, Li||Cu cells utilizing the ZSM electrolyte achieve an average coulombic efficiency (CE) of 98.76% over 700 h. Moreover, LiFePO₄||Li batteries exhibit stable cycling performance exceeding 900 cycles at a current density of 1 C. This design strategy offers robust support for effective interfacial regulation in lithium metal batteries. Full article

The global shortage of freshwater resources and the energy crisis have propelled solar-driven interfacial evaporation (SDIE) coupled with photocatalytic technology to become a research focus in efficient and low-carbon water treatment. Graphene-based materials demonstrate unique advantages in SDIE–photocatalysis integrated systems, owing to their broadband light absorption, ultrafast thermal carrier dynamics, tunable electronic structure, and low evaporation enthalpy characteristics. This review systematically investigates the enhancement mechanisms of graphene photothermal conversion on photocatalytic processes, including (1) improving light absorption through surface morphology modulation, defect engineering, and plasmonic material compositing; (2) reducing water evaporation enthalpy via hydrophilic functional group modification and porous structure design; (3) suppressing heat loss through thermal insulation layers and 3D structural optimization; and (4) enhancing water transport efficiency via fluid channel engineering and wettability control. Furthermore, salt resistance strategies and structural optimization significantly improve system practicality and stability. In water treatment applications, graphene-based SDIE systems achieve synergistic “adsorption–catalysis–evaporation” effects, enabling efficient the degradation of organic pollutants, reduction in/fixation of heavy metal ions, and microbial inactivation. However, practical implementation still faces challenges including low steam condensation efficiency, insufficient long-term material durability, and high scaling-up costs. Future research should prioritize enhancing heat and mass transfer in condensation systems, optimizing material environmental adaptability, and developing low-cost manufacturing processes to promote widespread application of graphene-based SDIE–photocatalysis integrated systems. Full article

Edge-capping modified MXene membranes with new channels created by lateral nanosheets are of great research significance. After introducing tripolyphosphate (STPP) to Ti edges of Ti₃C₂T_x nanosheets and fabricating the STPP-MXene membranes edge-capping method, this research investigated the performance optimization mechanism of STPP-modified MXene membranes in terms of salt permeability (NaCl, Na₂SO₄, MgCl₂, and MgSO₄) and transmembrane energy barriers (E_salt) through the concentration gradient permeation test. Experimental results demonstrated an approximately 1.86-fold enhancement in salt flux (J_s) compared to the MXene membranes. The solution–diffusion model was also introduced to evaluate the salt solubility (K_s) and diffusivity (D_s) during permeation. Furthermore, analysis of transmembrane energy barriers revealed that STPP modification induced significantly larger reductions in activation energy for magnesium salts (MgSO₄: 55.1%; MgCl₂: 47.4%) compared to sodium salts (NaCl: 30.5%; Na₂SO₄: 30.9%). This phenomenon indicated the weakened electrostatic interactions between high-valent Mg²⁺ and the modified lateral membrane Ti edges, whereas the limited charge density of Na⁺ resulted in relatively modest optimization. The results highlight the contribution of STPP capping on the edges of adjacent lateral nanosheets. Therefore, the modification increased the transportation rate of cations across the MXene membrane by more than twice, thus advancing the application of 2D MXene membranes in resource recovery. Full article

Dual-gate metal-oxide-semiconductor transistors have attracted considerable interest due to their high threshold voltage control capability, higher drain current, and the ability to alleviate the impact of carrier surface scattering at the channel/dielectric interface. However, their applications in the monolithic integration of scaled devices encounter challenges stemming from the interaction between the pre-treated channel layer and its covering dielectric. Here, we demonstrate the successful realization of a scaled back-end-of-line (BEOL) compatible dual-gate indium–gallium–zinc oxide (IGZO) transistor with a channel length (L_ch) scaled down to 150 nm and a channel thickness (T_ch) of 4.2 nm. After precisely adjusting the metal ratio to In_0.24Ga_0.58Zn_0.18O and employing O₃ as an oxygen precursor for the deposition of Al₂O₃ as the top-gate dielectric layer, a high maximum current of 1.384 mA was attained under top-gate control, while a high current of 1.956 mA was achieved under bottom-gate control. Additionally, a high current on/off ratio (I_on/off > 10⁹) was achieved for the dual gate. Careful calculations reveal that the field-effective mobility (μ_eff) reaches 11.68 cm²V⁻¹s⁻¹ under top-gate control and 22.46 cm²V⁻¹s⁻¹ under bottom-gate control. We demonstrate excellent dual-gate low-voltage modulation performance, with a high current switch ratio of 3 × 10⁵ at L_ch = 300 nm and 2 × 10⁴ at L_ch = 150 nm achieved by only 1 V modulation voltage, accompanied by a normalized current variation higher than 10⁶. Overall, our devices show the remarkable electrical performance characteristics, highlighting their potential applications in high-performance electronic circuits. Full article

With the advancement of industrial production and urban modernization, pollution from heavy metal ions and the accumulation of solid waste have become critical global environmental challenges. Establishing an effective recycling system for solid waste and removing heavy metals from wastewater is essential. Coal gangue was used in this study as the primary material for the synthesis of a fully coal gangue-based phosphorus-silicon-aluminum (SAPO-5) molecular sieve through a hydrothermal process. The SAPO-5 molecular sieve was characterized through several methods, including X-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface analysis, Fourier-transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS), to examine its mineral phases, microstructure, pore characteristics, and material structure. Adsorption performance towards wastewater with Cd²⁺ and Pb²⁺ ions was investigated. It was found that the adsorption processes of these ions are well described by both the pseudo-second-order model and the Langmuir isotherm. According to the Langmuir model, the coal gangue-based SAPO-5 molecular sieve exhibited maximum adsorption capacities of 93.63 mg·g⁻¹ for Cd²⁺ and 157.73 mg·g⁻¹ for Pb²⁺. After five cycles, the SAPO-5 molecular sieve retained strong stability in adsorbing Cd²⁺ and Pb²⁺, with residual adsorption capacities of 77.03 mg·g⁻¹ for Cd²⁺ and 138.21 mg·g⁻¹ for Pb²⁺. The excellent adsorption performance of the fully solid waste coal gangue-based SAPO-5 molecular sieve is mainly attributed to its mesoporous channel effects, the complexation of -OH functional groups, and electrostatic attraction. Full article

With the rapid development of the Internet of Things (IoT), there is an increasing demand for batteries with high energy and power densities. Three-dimensional microstructures present a promising approach for achieving high areal mass loading and an expanded electrochemical reaction surface. However, their high cost and complexity have hindered their widespread adoption. In this study, hierarchical porous electrodes integrated with conformal ultrathin nanosheets were fabricated to enhance reaction kinetics. The hierarchical porous skeleton provides a continuous pathway for electron transport and electrolyte diffusion, while the amorphous vanadium oxide (α-VO_x) nanosheets offer short ion diffusion channels and a large electrochemical surface area. Additionally, the internal space of the hierarchical structure accommodates substantial growth of the α-VO_x nanosheets, thereby supporting high mass loading and preserving areal capacity. The resulting hierarchical electrode structure demonstrates a high energy density of 0.49 mAh cm⁻² at 1 mA cm⁻² and an ultrahigh power density of 410 mW cm⁻² at 250 mA cm⁻². The assembled microbattery, using lithium metal as the anode, is encapsulated with a novel packaging process. This microbattery can power an electronic clock for up to 18 h on a single charge, retaining 75% of its initial capacity after 180 cycles. Full article

Copper ions (Cu²⁺) are the third most essential transition metal ions critical to human health. Rapid detection of Cu²⁺ in water and biological fluids is of significant importance. In this study, we develop a sensitive multi-channel paper microfluidic device integrated with a 3D-printed smartphone-based colorimetric reader for the rapid detection of Cu²⁺. A novel rhodamine derivative, 1-(N,N-dichloromethine) amino-4-rhodamine B hydrazine-benzimide (RBCl), exhibiting high selectivity and sensitivity to Cu²⁺, was synthesized and applied as the detection reagent. The interaction mechanism between RBCl and Cu²⁺ was investigated, revealing a structural transition from a colorless spirolactam (closed-ring) to an open-ring amide structure, resulting in a pink color upon Cu²⁺ binding. A multi-channel paper microfluidic device with eight detection zones was fabricated, enabling the simultaneous analysis of eight samples. To enhance portability and quantification, a 3D-printed smartphone colorimetric reader was integrated, providing a rapid and efficient detection platform. The system achieved highly specific Cu²⁺ detection within 2 min, with a detection limit as low as 1.51 ng/mL, meeting water monitoring standards in most countries. Excellent recoveries were demonstrated in real samples, including tap water, river water, blood serum, and urine diluent. This integrated paper microfluidic system is highly sensitive and specific, offering a promising solution for water quality monitoring and health assessment through its rapid sample-to-answer capability. Full article

Metal–organic frameworks (MOFs) with redox metal centers have come into view as potential materials for electrochemical energy storage. However, the poor electrical conductivity largely impedes the potentiality of MOFs to construct high-performance electrodes in supercapacitors. In this work, a self-dissociation strategy has been applied to construct Ni-MOF microbelts on Ni foam (NF), where the NF is used as both a support and a Ni source. The transmission channels between the Ni-MOF and NF are favorable for the charge transport due to the in situ self-assembly of the TPA linkers with the dissociated Ni ions from the Ni foam. The grown Ni-MOF microbelt arrays can offer abundant active sites for redox reactions. The prepared Ni-MOF/NF-s electrode can yield a high capacitance of 1124 F g⁻¹ at 1 A g⁻¹ and retains 590 F g⁻¹ at 10 A g⁻¹. This design may offer a controllable protocol for the construction of MOF microbelt arrays on various metal substrates. Full article

The intrinsic characteristic features of metal–organic frameworks offer unique, great opportunities to develop novel materials with applications in very diverse fields. Aiming to take advantage of these, the application of post-synthetic methodologies has revealed itself to be a powerful approach to the isolation and structuration of metal ions, molecules, or more complex species, either within MOF channels or reticulated at their network, rendering novel and exciting MOFs with new or improved functionalities. Herein, we report the partial post-synthetic metal exchange of Zn(II) metal ions by Co(II) ones in water-stable three-dimensional CaZn₆-MOF 1, derived from the amino acid S-methyl-L-cysteine, allowing us to obtain two novel MOFs with increasing contents of the Co(II) ions Co_4%@1 and Co_8%@1. Remarkably, the presented post-synthetic metal exchange methodology has two relevant implications for us: (i) it allowed us to obtain two novel MOFs, which were not accessible by direct synthesis, and (ii) enabled us to transform physical properties within this family of isoreticular MOFs from the diamagnetic pristine MOF 1 to MOFs Co_4%@1 and Co_8%@1, exhibiting field-induced, frequency-dependent, alternating current magnetic susceptibility signals, which are characteristic features of single-molecule magnets. Full article

Cronobacter sakazakii, an opportunistic foodborne pathogen, has a strong resistance to osmotic stress and desiccation stress, but the current studies cannot elucidate this resistance mechanism absolutely. A mechanosensitive channel MscM was suspected of involving to desiccation resistance mechanism of C. sakazakii. To investigate the specific molecular mechanism, the mscM mutant strain (ΔmscM) was constructed using the homologous recombination method, and the cpmscM complementary strain was obtained by gene complementation, followed by the analysis of the difference between the wild-type (WT), mutant, and complementary strains. Compared to the wild-type bacteria (WT), the inactivation rate of the ΔmscM strain decreased by 15.83% (p < 0.01) after desiccation stress. The absence of the mscM gene led to an increase in the membrane permeability of mutant strains. Through turbidity assay, it was found that the intracellular content of potassium ion (K⁺) of the ΔmscM strain increased by 2.2-fold (p < 0.05) compared to the WT strain, while other metal ion contents, including sodium ion (Na⁺), calcium ion (Ca²⁺), and magnesium ion (Mg²⁺), decreased by 48.45% (p < 0.001), 24.29% (p < 0.001), and 26.11% (p < 0.0001), respectively. These findings indicate that the MscM channel primarily regulates cell membrane permeability by controlling K⁺ efflux to maintain the homeostasis of intracellular osmotic pressure and affect the desiccation tolerance of bacteria. Additionally, the deletion of the mscM gene did not affect bacterial growth and motility but impaired surface hydrophobicity (reduced 20.52% compared to the WT strain, p < 0.001), adhesion/invasion capability (reduced 26.03% compared to the WT strain, p < 0.001), and biofilm formation ability (reduced 30.19% compared to the WT strain, p < 0.05) of the bacteria. This study provides a reference for the role of the mscM gene in the desiccation resistance and biofilm formation of C. sakazakii. Full article

Common oat (Avena sativa L.) is one of the important minor grain crops in China, and drought stress severely affects its yield and quality. To investigate the drought resistance characteristics of oat seedlings, this study used Baiyan 2, an oat cultivar at the three-leaf stage, as the experimental material. Drought stress was simulated using polyethylene glycol (PEG) to treat the seedlings. The photosynthetic parameters and physicochemical indices of the treatment groups at 6 h and 12 h were measured and compared with the control group at 0 h. The results showed that drought stress did not significantly change chlorophyll content, but it significantly reduced net photosynthetic rate and other photosynthetic parameters while significantly increasing proline content. Transcriptome analysis was conducted using seedlings from both the control and treatment groups, comparing the two treatment groups with the control group using Tbtool software (v2.136). This analysis identified 344 differentially expressed genes. Enrichment analysis of these differentially expressed genes revealed significant enrichment in physiological pathways such as photosynthesis and ion transport. Ten differentially expressed genes related to the physiological process of photosynthetic carbon assimilation were identified, all of which were downregulated. Additionally, seven differentially expressed genes were related to ion transport. Through gene co-expression analysis combined with promoter region structure analysis, 11 transcription factors (from MYB, AP2/ERF, C2C2-dof) were found to regulate the expression of 10 genes related to photosynthetic carbon assimilation. Additionally, five transcription factors regulate the expression of two malate transporter protein-related genes (from LOB, zf-HD, C2C2-Dof, etc.), five transcription factors regulate the expression of two metal ion transporter protein-related genes (from MYB, zf-HD, C2C2-Dof), five transcription factors regulate the expression of two chloride channel protein-related genes (from MYB, bZIP, AP2/ERF), and two transcription factors regulate the expression of one Annexin-related gene (from NAC, MYB). This study provides a theoretical foundation for further research on the molecular regulation of guard cells and offers a molecular basis for enhancing drought resistance in oats. Full article