Latest ArticlesMatrix-assisted laser desorption ionization-mass spectrometry imaging (MALDI-MSI) has shown its capability in visualizing the spatial distribution of various kinds of endogenous metabolites. Nevertheless, high quality mass imaging of low polar metabolites remains challenging. Herein, a platform for sensitive matrix-assisted laser desorption ionization-mass spectrometry imaging of cholesterol and glycerides has been proposed. In the platform, a vacuum promoted on-tissue derivatization strategy was proposed to constantly make the derivatization reaction proceed towards to the direction of products. Compared with traditional on-tissue derivatization procedure, the strategy improved the acquired intensity of derivatized glycerides about 50%. Additionally, the mass spectrometry image reflecting the signal ratio between 3 classes of glycerides was achieved to exploit the metabolic level of glycerides on tissue slice. Finally, the platform was applied to brain slices of Alzheimer's transgenic mice, type 2 diabetes mice and normal mice. Significant difference was found in mass spectrometry images reflecting the signal ratio of multiple endogenous metabolites. The work constructed a promising platform for mapping of glycerides in tissue by mass spectrometry imaging.
Electrocatalytic reduction of nitrate (NO3−) at low concentrations to ammonia (NH4+) still faces challenges of low NO3− conversion and NH4+ selectivity due to the sluggish mass transfer and insufficient atomic hydrogen (H*) supply. Herein, we propose CuO/NiO heterojunction with the assistance of a built-in electric field to enhance mass transfer and H* provision. The built-in electric field in CuO/NiO is successfully formed as demonstrated by X-ray photoelectron spectroscopy and ultraviolet photoemission spectroscopy. The results reveal that CuO/NiO achieves high NO3− reduction activity (100%) and NH4+ selectivity (100%) under low NO3− concentration conditions (100 mg/L NO3−, ca. 22.6 mg/L NO3−-N), which is superior to that of many recently reported electrocatalysts. Density functional theory calculations further clarify that the built-in electric field triggers the enhanced adsorption of reactants on CuO/NiO heterojunction interface and strong d-p orbital hybridization between reactants and CuO/NiO. Besides, the free energy diagram of hydrogen evolution reaction of CuO/NiO confirms the realization of enhanced H* provision. Moreover, coupling experiments and consecutive cycle tests demonstrate the potential of CuO/NiO in practical applications. This work may open up a new path and guide the development of efficient electrocatalysts for electrocatalytic reduction of NO3− at low concentrations to NH4+.
Ensuring the timely and precise monitoring of severe liver diseases is crucial for guiding effective therapies and significantly extending overall quality of life. However, this remains a worldwide challenge, given the high incidence rate and the presence of strong confounding clinical symptoms. Herein, we applied a convenient and high-yield method to prepare the magnetic mesoporous carbon (MMC-Fe), guided by a composite of resol and triblock copolymer. With the combination of MMC-Fe, high-throughput mass spectrometry, and a simple machine learning algorithm, we extracted N-glycan profiles from various serum samples, including healthy controls, liver cirrhosis, and liver cancer, and from which we screened specific N-glycans. Specifically, the selected N-glycans demonstrate exceptional performance with area under the curve (AUC) values ranging from 0.948 to 0.993 for the detection of liver diseases, including alpha fetoprotein (AFP)-negative liver cancer. Among them, five N-glycans holds potential in monitoring distinctions between liver cirrhosis and AFP-negative liver cancer (AUC values of 0.827–0.842). This study is expected to promote the glycan-based precise monitoring of diseases, not limited to liver disease.
Fenton-like process based on metal oxide presents one of the most hoping strategies to generate reactive oxygen species to treat refractory pollutants. The introduction of oxygen vacancies (OVs) can enhance the catalytic performance of metal oxides in Fenton-like reaction. In this paper, a one-step all solid-state synthesis strategy is proposed to induce oxygen defects in V2O5, which uses graphene to engineer the crystallization process of V-based crystals. Such approach employs graphene as a solid-catalyst to promote growth of V-based crystals owing to the ions-π interactions between graphene and VCl3. The electron-donor OVs in V2O5@graphene can not only active H2O2 for the •OH generation, but also accelerate the reduction of V5+ and V4+, thereby ensuring defective V2O5@graphene/H2O2 system is 14.3, 28.2, and 17.3 times higher than that of graphene/H2O2, pure V2O5/H2O2 and graphene+V2O5/H2O2 (mechanical mixed system), respectively. Our study provides a novel synthetic strategy to design and prepare OVs-riched transition metal catalysts for developing advanced oxidation technologies toward higher sustainability and practicality.
Since the discovery of the Nernst effect in 19th century, it has been an important transverse thermoelectric charge transport phenomenon in solid states. Conjugated polymers have recently attracted great attention as promising optoelectronic materials. However, the Nernst effect is yet to be explored for conducting polymers. Here, we report the first theoretical investigations of the Nernst effect in doped conducting polymers by first-principles calculations under the frame work of Fermi-liquid theory. Specifically, the Nernst coefficients of PBTTT are found to be ranging from 0.0029 to 0.039 µV K−1 T−1. They are monotonically decreased with the doping level due to both much enhanced Fermi energy and the decreased charge mobility at high doping level. Our theoretical findings not only enhance our fundamental understanding of the doping mechanism that controls the charge transport properties of conducting polymers, but more importantly, they also offer initial predictions of the transverse thermoelectric conversion capability of conducting polymers. These predictions are crucial for the development of future flexible thermoelectric applications based on the Nernst effect.
β-Amino sulfides hold significant biological importance, motivating the development of several methods for sulfenylamination of alkenes. However, these methods often involve a three-component system with limited alkene substrate range. In this study, we present a pioneering two-component approach utilizing readily accessible sulfenamides as efficient difunctionalization reagents. Key to its success is the careful selection of a suitable photosensitizer, which enables precise modulation of sulfenamides by promoting unprecedented energy transfer rather than traditional single-electron oxidation. This novel strategy leads to the concurrent formation of N- and S-radical species, ensuring high regioselectivity for both electron-neutral and electron-deficient alkenes. As a result, a wide range of valuable β-amino sulfides, including those with congested amine groups, can be readily synthesized. These findings highlight the potential of this method for the efficient synthesis of diverse functionalized β-amino sulfides.
Herein, a diatomite biomorphic Si-O doped carbon-based catalyst (DB-SiOC) was prepared using natural mineral diatomite as the silicon source and porous template. The results showed that the metal-free DB-SiOC catalyst exhibited ultrafast oxidation towards chlorophenol (CP) via peroxymonosulfate (PMS) activation, which was almost one order of magnitudes than most of carbon-based catalysts. The DB-SiOC/PMS system also showed the high ability to resist the interference of environmental matrix. The radicals (•OH and SO4•‒) exhibited a very small contribution to the CP oxidation while the electron transfer processes (ETP) played the major role in the DB-SiOC/PMS system. The electron shuttles from the electron-donating CP molecules to the adjacent DB-SiOC/PMS* could be efficiently triggered via Si-O bonds as bridges, making it possible for ultrafast oxidation of CP. In addition, the hollow-disc shaped DB-SiOC provided the biomorphic DE structures with abundant pores for enriching the PMS and pollutants, thus further accelerating the oxidation reaction. This work provided a new routine for the fabrication of Si-O doped carbon-based catalysts with excellent Fenton-like catalytic activity, which would greatly promote their application prospects in Fenton-like systems.
Carbon nitride, a typical low-dimensional conjugated polymer photocatalyst, features a high exciton binding energy due to the weak dielectric screening and the strong Coulombic attraction of photogenerated electrons and holes. The reduction of the exciton binding energy of carbon nitride to promote the conversion from excitons into free carriers is the first priority for the improvement of charge-transfer-dependent photocatalytic reaction activity. In this paper, by introducing a variety of polar metal cations to carbon nitride, it is demonstrated that the charge distribution of the heptazine ring can be improved by ion polarization, which effectively promotes the dissociation of excitons into electrons and holes. The sodium ion shows the best modification effect, which enhances the rate of both photocatalytic hydrogen and hydrogen peroxide production by about 50%. Characterization shows that the introduction of strongly polar metal cations contributes to the reduction of the exciton dissociation energy of carbon nitride. This study provides a new perspective and a convenient method for the exciton modulation engineering of low-dimensional photocatalysts.
BiVO4 is a promising semiconducting photoanode for photoelectrochemical (PEC) water splitting due to its suitable bandgap. However, the dissolution of V5+ and sluggish reaction kinetics at the surface in the oxygen evolution reaction (OER) limit its applications. Herein, we report a convenient strategy to change the microenvironment by adding Fe(Ⅲ) into the electrolyte. During the PEC process, Fe(Ⅲ) ions not only improve the current density, but also show excellent stability toward BiVO4. Consequently, the current increases by more than 1.7 times compared to that without Fe(Ⅲ). Photoelectrochemical, morphological, and structural characterizations reveal that the FeOOH co-catalyst produced in situ on the BiVO4 photoanode by cyclical formation of the intermediates at the electrode/electrolyte interface during OER accelerates the OER kinetics and prevents photo-corrosion by suppressing the dissolution of V5+. The results reveal a new strategy for the multifunctional modification of photoanodes for efficient solar conversion.
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