化学最新文献

The development of efficient photocatalysts for solar-driven hydrogen production is crucial for addressing energy and environmental challenges. Herein, a full-spectrum responsive "dual-engine" photocatalytic system based on a multifunctional cocatalyst featuring electrons extraction, photothermal heating effect and abundant active sites was successfully designed. In this system, hierarchical NiCo₂S₄ (NCS)/defective ZnCdS (ZCS-Vs) composite photocatalysts were synthesized through a simple physical mixing method with hierarchical NCS modified ZCS-Vs nanoparticles. Owing to the introduction of black hierarchical NCS, these composite photocatalysts show a wide light absorption range from 300 to 1200 nm due to the introduction of black hierarchical NCS. Under broad-spectrum illumination, the optimized photocatalyst delivered a maximum H₂ production rate of 22.19 mmol·g^-1·h^-1 and an apparent quantum yield of 6.29 % at 420 nm, corresponding to roughly a 42-fold improvement over pure ZCS-Vs. This outstanding H₂ evolution performance originates from three key factors. First, the metallic nature and high work function of NCS enable the formation of a Schottky junction with ZCS-Vs, which efficiently extracts photogenerated electrons from ZCS-Vs for the reduction of H⁺ ions. Second, under photoexcitation, NCS exhibits a strong localized surface plasmon resonance (LSPR) effect, leading to a rapid increase in local temperature on the catalyst surface. This localized heating further elevates the overall reaction solution temperature, thereby reducing the energy barrier for photocatalytic H₂ evolution. Third, 3D hierarchical structure of NCS not only inhibits nanoparticle aggregation and provides abundant active sites, but also enhances light harvesting through internal scattering, thereby maximizing both charge separation and photothermal efficiency. Consequently, this "dual-engine" photocatalytic system provides a feasible pathway for designing photothermal-assisted composite photocatalysts to enhance photocatalytic H₂ evolution efficiency.

Ruthenium-based materials are widely regarded as promising electrocatalysts for water splitting, owing to their platinum-like electronic characteristics and favorable binding energies with reaction intermediates. Nevertheless, the oxidation behavior of ruthenium at elevated potentials induces structural degradation, precipitating the dissolution of active species and thereby undermining stability during the oxygen evolution reaction (OER) in acidic media. Herein, we reported a novel RuO₂@Ru heterostructured catalyst with cobalt and copper co-doping (Co, Cu-RuO₂@Ru) for stable acidic water electrolysis. The heterostructured catalyst exhibited exceptional performance, attaining an ultralow overpotential of 182 mV at 10 mA cm^-2 for the OER and a low overpotential of 217 mV at 250 mA cm^-2 for the hydrogen evolution reaction (HER), surpassing the benchmark Pt/C catalyst. Electronic-structure analyses indicated that the RuO₂@Ru heterointerface promoted charge redistribution following Co and Cu co-doping, effectively reducing the oxidation state of ruthenium within RuO₂ and yielding an electron-deficient metallic Ru phase. Moreover, mechanistic investigations revealed that electron transfer induced by Co and Cu co-doping optimizes the adsorption and desorption kinetics of hydrogen and oxygenated intermediates, thereby accelerating the reaction kinetics of both HER and OER in acidic media, ultimately leading to exceptional overall water splitting performance.

Realizing Zn metal anodes with long lifespan performance is a prerequisite for the commercialization of Zn-ion batteries, which is limited by severe water erosion, side reactions and dendrite formation. Herein, a series of hydrophilic metalloporphyrin coatings were employed to stabilize the Zn anode by screening their central metal sites from Mn to Zn. Among them, central copper (Cu²⁺) site significantly blocks the competitive hydrogen evolution reaction (HER) by elevating the adsorption barrier for the hydrogen proton intermediate (H*), suppressing both Heyrovsky and Tafel steps. Consequently, the HER overpotential of CuTCPP@Zn is increased while parasitic side reactions are reduced. Furthermore, the enhanced zincophilicity of CuTCPP@Zn facilitates a high Zn²⁺ transfer number of 0.70, which promotes uniform nucleation and deposition. As a result, CuTCPP@Zn delivers a stable cycling life exceeding 1460 h at 1 mA cm^-2 and 453 h even at 5 mA cm^-2. This work provides insights for precisely altering intrinsic HER activity by regulating central metal sites of hydrophilic metalloporphyrin coatings from a thermodynamic perspective, thereby realizing the construction of stable Zn metal anodes.

Background: The use of current metric tools for sample preparation has proven highly valuable in identifying the strengths and weaknesses of various analytical approaches. However, as Analytical Sciences increasingly move towards sustainability, it becomes evident that existing metrics may not fully cover all the dimensions required for a comprehensive assessment.

Results: An overview to encourage the evolution towards more advanced metric tools for sample preparation by reflecting on which parameters should be evaluated and on the principles that ought to guide their design. The tutorial highlights the need for new or improved metrics capable and identify the most relevant criteria and how they can be integrated. The discussion is particularly focused in the context of miniaturization and the development of new extractive materials. Through case studies, solvents and sorbents are examined using analytical performance, green, and market-related criteria, emphasizing the importance of integrating these perspectives into future tools. Solid-phase (SPME) and liquid-phase microextraction (LPME) are evaluated using the metric tools currently available, pointing out the challenges associated with the application. The results reveal the need to advance towards more advanced metric tools contextualizing the outcomes within the complexity of the analytical problem.

Significance and novelty: This manuscript highlight the need to advance metric tools towards models capable of integrating environmental, analytical, and practical dimensions within a coherent sustainability-oriented framework. The tutorial offers guidance for researchers and developers aiming to create more effective tools for the design and evaluation of sample preparation methods, tools that not only address greenness but also deliver greater robustness, relevance, and applicability in real analytical scenarios.

Dielectric barrier discharge ionization (DBDI) sources, employing low-temperature plasma, have emerged as sensitive and efficient ionization tools with various atmospheric pressure ionization processes. In this review, we summarize a historical overview of the development of DBDI, highlighting key principles of gas-phase ion chemistry and the mechanisms underlying the ionization processes within the DBDI source. These processes start with the formation of reagent ions or metastable atoms from the discharge gas, which depends on the nature of the gas (helium, nitrogen, air) and on the presence of water vapor or other compounds or dopants. The processes of ionizing the analyte molecules are summarized, including Penning ionization, electron transfer, proton transfer and ligand switching from secondary hydrated hydronium ions. Presently, the DBDI-MS methods face a challenge in the accurate quantification of gaseous analytes, limiting its broader application in biological, environmental, and medical realms where relative quantification using standards is inherently complex for gaseous matrices. Finally, we propose future avenues of research to enhance the analytical capabilities of DBDI-MS.

This review delves into the efficacy of utilizing bubbles to extract analytes into the gas phase, offering a faster and greener alternative to traditional sample preparation methods for mass spectrometry. Generating numerous bubbles in liquids rapidly transfers volatile and surface-active species to the gas phase. Recently, effervescence has found application in chemical laboratories for swiftly extracting volatile organic compounds, facilitating instantaneous analysis. In the so-called fizzy extraction, liquid matrices are pressurized with gas and then subjected to sudden decompression to induce effervescence. Alternatively, specifically designed effervescent tablets are introduced into the liquid samples. In situ bubble generation has also enhanced dispersion of extractant in microextraction techniques. Furthermore, droplets from bursting bubbles are collected to analyze non-volatile species. Various methods exist to induce bubbling for sample preparation. The polydispersity of generated bubbles and the limited control of bubble size pose critical challenges in the stability of the bubble-liquid interface and the ability to quantify analytes using bubble-based sample preparation techniques. This review covers different bubble-assisted sample preparation methods and gives practical guidance on their implementation in mass spectrometry workflows. Traditional, offline, and online approaches for sample preparation relying on bubbles are discussed. Unconventional bubbling techniques for sample preparation are also covered.

Ambient and direct mass spectrometry (MS) methods are becoming increasingly used for the rapid analysis of food, beverage and agricultural samples. Novel ionization approaches combined with targeted, or untargeted workflows provide analytical outcomes within a greatly reduced time period compared to traditional separation science coupled with MS detection. This review will provide an overview of atmospheric pressure ionization MS based techniques for analysis of food, beverage and agricultural samples, with an emphasis on direct and rapid analysis including ambient ionization. The review will be completed through presentation of relevant examples of the use of ambient ionization techniques for food and beverage analysis along with the authors perspectives for future challenges relevant to the field.

In the 1980s, researchers discovered the remarkable ability of electrospray plumes to effectively ionize gas-phase molecules via secondary ionization. Around 20 years later-coinciding with the ambient mass spectrometry revolution-secondary electrospray ionization (SESI) and extractive electrospray ionization (EESI) coupled to mass spectrometry were revisited and further developed to analyze complex mixtures of gas and aerosol samples in real-time yet with high sensitivity. During the past two decades, these mass spectrometric techniques have been applied across a broad range of applications, such as the detection of illicit drugs, environmental aerosol analysis, and a series of metabolomic studies through the analysis of volatiles emitted from living organisms. This review offers a comprehensive overview of the progress of SESI and EESI applications since their emergence. Finally, we discuss the opportunities, challenges, along with future directions of SESI and EESI techniques.