摘要 : Merging proton relay ligands to metal catalysts has proven to be an effective route for regulating the proton transfer and enhancing efficiency in CO 2 reduction reactions (CO 2 RR). The structure-activity relationship for these synergistic ligands remains barely explored. We herein functionalized Si/ZnO/Au photocathodes with proton relay ligands and investigated their activity for CO 2 -to-CO transformations. A series of ligands with varied acid-base properties (pK a : ∼3–10) were selected and compared, which eventually found a volcano-shape dependence of CO 2 photoconversion on the ligands' pK a . The electrode functionalized with 2-mercaptoimidazole (pK a = 8) was optimal and effectively elevated the CO selectivity by ∼2 folds, furnishing 84 % CO Faradic efficiency (FE CO ) at 0 V (vs. RHE) with > 20 h operation stability. In the mechanistic investigations, we successed to link the protonation/deprotonation abilities (defined by pK a ) of the ligands to the kinetics of the crucial COO − /COOH formation steps. Ultimately, we found that achieving a balance between these two steps, facilitated by a ligand with a medium pK a, maximizes the CO 2 reduction selectivity.

摘要 : Traditional Simultaneous Localization and Mapping (SLAM) systems assume static environments, and their localization accuracy degrades significantly when encountering dynamic objects. Although dynamic SLAM based on semantic information can handle simple dynamic objects, it fails to address the impact of pseudo-dynamic objects and unrecognized dynamic objects on pose estimation. To address these issues, we propose a DC-SLAM system, comprehensively eliminating two types of dynamic features while preserving valid static features. The system implements a dual-category mechanism: for active dynamic features, it combines a dynamic object detection network with dense optical flow for detection and removal, preventing excessive elimination of static features' for passive dynamic features, the system first determines their attributes using multi-view geometry, then clusters all feature points based on depth information and object detection categories, and finally optimizes dynamic properties through Mahalanobis distance analysis of outlier similarity. This approach compensates for the limitations of multi-view geometry, enabling more effective suppression of passively dynamic objects. Additionally, an octree mapping module is developed to assist mobile robots in scene understanding for practical applications. Extensive experiments on the TUM dataset, Bonn dataset, and real-world dynamic scenes verify DC-SLAM's effectiveness. The results demonstrate significant improvements, compared with ORB-SLAM2, DC-SLAM reducing Absolute Trajectory Error (ATE) by 98.86 % and Relative Pose Error (RPE) by 97.28 %, while enabling the reliable construction of octree maps to enhance spatial understanding.

摘要 : Mass lumping of flexure beams plays a critical role in the dynamic compliance matrix method (DCM) for both kinetostatic and vibration analyses of compliant mechanisms and structures. The primary objective of this study is to derive and compare various mass matrix formulations for use in the DCM. Continuous and diagonal lumped mass matrices of flexure hinges and beams as well as their local-to-global coordinate transformation formulations are derived, discussed and clarified. By virtue of mass lumping and grounding, the schemes of compliance matrix summation for serial beam chains and stiffness/mass matrix summation for parallel branches are developed considering damping effects. The performance of different mass matrices is evaluated through case studies, which highlight the variation in performance with different mass matrices. The established mass matrix library of general flexure hinges and beams enhances the robustness of the DCM, and thus offers a straightforward performance-oriented analysis tool for compliant mechanisms and beam structures in terms of dynamic compliance.

摘要 : This study aims to improve the applicability of green-synthesized nano zero-valent iron (GT-nZVI) for wastewater treatment under natural pH conditions by developing a novel -nZVI composite stabilized with polystyrene sulfonate (PSS) and green tea polyphenols (GT-nZVI@PSS) at different PSS/Fe mass ratios (0.01–0.5) for Pb(II) removal. Particular emphasis was placed on elucidating the influences of humic acid (HA) and sulfate ubiquitous constituents in wastewaters on Pb(II) removal performance, with the underlying mechanisms of their effects systematically clarified. Results demonstrated that GT-nZVI@PSS (PSS/Fe = 0.05) exhibited excellent Pb(II) removal at neutral pH, primarily driven by enhanced Pb(II) reduction and Pb 0 precipitation. This performance is mainly attributed to improved dispersibility resulting from the synergistic effects of PSS and tea polyphenols on the particle surface. HA and sulfate exerted opposing effects on Pb(II) removal by GT-nZVI@PSS. At low concentrations, HA enhanced Pb(II) uptake by increasing the surface negative charge, improving particle dispersion, and providing additional active sites for the formation of Fe–HA/Pb complexes. In contrast, sulfate inhibited Pb(II) removal by disrupting the polyphenol coating and forming surface sulfate–iron species and PbSO 4 precipitates, thereby accelerating passivation and reducing Fe release. However, at high concentrations, excessive HA molecules formed large aggregates that enveloped the particle surfaces, ultimately hindering Pb(II) access to the active sites of GT-nZVI@PSS. Conversely, high concentrations of sulfate promoted GT-nZVI@PSS corrosion, facilitating Fe 0 release and thereby enhancing Pb(II) removal. These findings highlight the crucial role of water matrix constituents in modulating the performance of GT-nZVI@PSS, as an eco-friendly and cost-effective material.

摘要 : The oxygen evolution reaction (OER), as the core half-reaction in water electrolysis (WE), plays a decisive role in determining the overall efficiency of hydrogen production. Cobalt carbonate hydroxide (CoCH) has recently emerged as a attractive material for alkaline OER due to its robust structural stability. In this study, urchin-like CoCH was employed as a precursor template to synthesize Fe and Mn co-modified CoCH catalyst on nickel foam (NF) through Mn-doping and surface Fe-modification strategies (recorded as Fe, Mn-CoCH/NF). This optimized hierarchical structure enhanced the exposure of active sites and facilitated faster electron/mass transport paths. The incorporation of Fe and Mn effectively regulated the position of d-band center and facilitated a more efficient lattice oxygen mechanism (LOM) for OER, thereby enhancing the intrinsic activity of the catalyst. Compared to the unmodified CoCH/NF, the Fe, Mn-CoCH/NF exhibited significantly improved OER catalytic activity, characterized by a substantially reduced overpotential (204 mV at 10 mA cm −2 ) in alkaline electrolyte, alongside remarkable stability. Utilizing this catalyst, an overall water splitting (OWS) system was further developed, capable of driving efficient OWS at a low cell voltage (1.49 V at 10 mA cm −2 ). Furthermore, the unique hierarchical structure of Fe, Mn-CoCH/NF contributed to mitigating electrochemical corrosion and the toxic effects of Cl − during seawater electrolysis, enabling the catalyst to maintain excellent catalytic activity and stability even in alkaline seawater system.

摘要 : SnS2 has emerged as a promising anode material for sodium-ion batteries (SIBs) due to its ultrahigh theoretical specific capacity (1136 mAh g −1 ) and large interlayer spacing (5.9 Å). However, its practical application is severely hindered by significant volume expansion and poor intrinsic conductivity. In this work, SnS2@GO was successfully synthesized via a reflux method. The integration of SnS2 with GO not only enhance the overall conductivity but also yield ultrasmall nanoparticles which shorten the diffusion pathways for Na + and electrons while mitigating volume expansion. As a result, SnS2@GO demonstrates exceptional electrochemical properties, including outstanding cycling performance (1120 mAh g −1 at 0.1 A g −1 ), remarkable rate capability (788 mAh g −1 at 5 A g −1 ), and superior long-term cycling stability (588 mAh g −1 at 5 A g −1 after 1200 cycles), highlighting its great potential for the applications of SIBs.

摘要 : Owing to the extensive use of solid fuels (e.g., coal, charcoal, and biomass), massive smoke dissolved organic matters (SDOMs) are produced. They are not only deteriorate atmosphere, but eventually deposit into water and soil environments, and interact with pollutants (e.g., heavy metals (HMs)), further altering the environmental fate and risks of HMs. However, the distinct molecular complexing mechanisms of SDOMs from various solid fuels combustion toward HMs still remains unknown. This study investigated the distinct molecular complexing mechanisms with Cu(II) and Cd(II)) (0–100 μmol/L) for SDOMs (10 mg-C/L) from coal, charcoal, and biomass based on Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), two dimensional fluorescence excitation-emission matrix (EEM) and Fourier transform infrared spectroscopy (FTIR). Notably, various SDOMs exhibited evidently different molecular complexing characteristics with HMs. Fluorescence quenching/enhancing ratio showed that humic-like matters in biomass SDOMs (28.7–51 %) were significantly combined with HMs, and polyphenols in coal and charcoal SDOMs (7.3–38.4 %) were significantly combined with HMs. Coal-derived SDOM was rich in CHOS compounds (−SO 3 H group) which played a dominant role in the binding capacity toward HMs, with the binding sequence preceded CHON and CHONP compounds. Charcoal-derived SDOM featured N-containing compounds (–NH 2 group), which formed H-bonds with S-/P-containing compounds and competed against HMs binding, leading highly aromatic CHO compounds to preferentially interact with HMs via cation-π effect. Biomass-derived SDOMs possessing the maximum CHO compounds which provided more multi-oxygen coordination sites for HMs complexing, but CHON, CHOS and CHOP compounds interacting with HMs preceded CHO compounds. The complexing order of functional groups followed phenol-O - >S=O/P-O/–NH > aromatic C=C > –OH. This study elucidated distinct molecular mechanisms of various SDOMs binding with HMs according to their molecular compositions and functional group types. The results are essential to understanding and controlling the geochemistry process and environmental fate of various solid fuels-derived SDOM-HMs complexes in surface environments.

摘要 : The fluidic diode characteristic of Tesla structure is regarded as a promising approach to regulate the thermo-hydrodynamic performance of flow boiling in microchannels. In this study, we introduced the Tesla structure to construct the boiling microchannel, and two types of Tesla-microchannels, including saw-like Tesla-microchannel and island-inserted Tesla-microchannel, are fabricated. The thermo-hydrodynamic performances of these two microchannel evaporators are experimentally investigated and compared with corresponding parallel microchannel. The effects of heat flux, inlet subcooling, and flow rate on thermo-hydrodynamic performances are examined. In addition, the advantages and limitations of Tesla-microchannel evaporators from the application-oriented view are also analyzed. The results indicate that Tesla-microchannel can always improve the critical heat flux when compared with that of parallel microchannel. The island-inserted Tesla-microchannel achieved the highest critical heat flux, which is attributed to the back-flow inhibition effect of Tesla-bend and Tesla-island. However, it is difficult to sustain stable liquid film in the Tesla structure. As a result, only under large subcooling conditions can the Tesla-microchannel obtain higher heat transfer coefficient than that of parallel microchannel. Special attention should be also paid to the phenomenon that the bubble collapse effect of Tesla-island can effectively reduce pressure drop. Compared with saw-like Tesla-microchannel and parallel channel, the pressure drop of island-inserted Tesla-microchannel is significantly decreased at different flow rates.

摘要 : Developing carbon-based single-atom adsorbents (SAAs) requires a deep understanding of the impact of the coordination environment during adsorption. In this study, the adsorption behavior and mechanism of benzene molecules on N/O coordinated carbon-based Fe SAA (Fe/SAA) were investigated using density functional theory calculations combined with experimental verification. The computational results indicated that the high magnetic moment and charge redistribution at the Fe sites induced polarization of p-orbital electrons in benzene rings. Furthermore, N/O equilibrium coordination optimized the Fe d -orbital energy level and enhanced hybridization between the Fe d -orbitals and the C p -orbitals of benzene. Among the studied configurations, the Fe-N 2 O 2 -II configuration exhibited the best adsorption effect toward benzene, with an adsorption energy of −0.685 eV, representing a 59 % improvement compared with the pure carbon substrate. It is worth noting that O coordination directly participates in adsorption through O p -orbital/C p -orbital interactions, further enhancing adsorption stability. N/O co-coordinated Fe single-atom materials were successfully prepared using chestnut shells as biomass-derived carbon substrates, with the Fe-N 2 O 2 /ORC (ORC: oxygen-rich carbon substrate) material demonstrating superior benzene removal efficiency. This study elucidates the key mechanism of regulating the coordination environment of Fe single-atom sites to enhance the adsorption of volatile organic compounds like benzene, providing a strategy for designing efficient materials for indoor benzene pollution control.

摘要 : Accurate detection of mitochondrial peroxynitrite (ONOO − ) is crucial for elucidating its roles in physiological and pathological processes. However, its detection remains challenging due to its short half-life, low concentration, and interference from reactive species. To address this, we developed an activatable AIE fluorescent probe, NN-3, which achieves high selectivity through an addition-elimination reaction involving its diphenylphosphinyl group. Upon ONOO − -mediated cleavage of the phosphoester bond, the probe exhibits a significant fluorescence enhancement of up to 3062-fold. NN-3 provides a quantitative response to ONOO − over a wide concentration range (5–50 μM), with an ultra-low detection limit of 7.0 nM and rapid response characteristics, while maintaining excellent resistance to biological interference. Furthermore, the probe successfully imaged dynamic ONOO − concentrations in the mitochondria of living cells, exhibiting excellent cell membrane permeability and negligible cytotoxicity.