Latest ArticlesNH3-SCR was one of the most promising deNOx technologies and it has been widely applied in industrial NOx reduction. However, with the further development of energy transformation in power generation sector, the development of NH3-SCR catalysts is facing some new challenges. It is becoming an urgent problem to solve low catalytic activity and stability of NH3-SCR catalysts at the working condition of ultra-low temperature (≤ 200 ℃) and high concentrations of H2O + SO2 due to the gradual deployment of new energy power plants. Furthermore, the traditional coal-fired power plants would need flexible operation with the increasing share of renewable energy generation. The NH3-SCR catalysts which were applied in coal-fired power industry would be requested to work in a wide temperature window from 200 ℃ to 500 ℃ in the near future. Therefore, in this review, we summarized the progress of NH3-SCR catalysts in solving these different industrial problems in recent years. And the research directions which were deserved to be focused on the development of NH3-SCR catalysts for the energy transition of power generation sector are proposed.
Low-molecular-weight (LMW) compounds are ubiquitous in living organisms and play essential roles in biological processes. The direct analysis of LMW compounds in biological tissues by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) could provide a more comprehensive understanding of their essential functions. Here, we evaluated 4-nitrocatechol (4-NC) as a novel positive-ion matrix for enhancing in situ detection and imaging of LMW compounds from the rat liver, brain, and germinating Chinese-yew seed by MALDI-MS. Our results showed that the 4-NC possessed remarkable features, including strong ultraviolet absorption, uniform matrix crystal, excellent chemical stability, and fewer matrix-related background peaks. The use of 4-NC led to the successful detection of 232, 218, and 193 LMW compounds from the three abovementioned tissue sections, respectively. Also, the use of 4-NC improved the imaging quality of LMW compounds in tissue sections through MALDI-MSI and has the potential as a matrix for MALDI tissue imaging of LMW compounds.
Three novel matrine-type alkaloids (1–3) and two unprecedented aloperine-type alkaloids (4 and 5) were isolated from the root of Sophora tonkinensis and the seeds of Sophora alopecuroides respectively. Notably, compound 1 possessed an unprecedented 6/5/6 tricyclic skeleton, while compounds 2 and 3 characterized by rare 6/6/5/6 tetracyclic system and 6/6/6/6/6 pentacyclic system respectively. Moreover, compound 4 possessed an unprecedented 6/7/6/6 tetracyclic core, and compound 5 characterized by rare 6/6/6/6 tetracyclic skeleton. Their structures were elucidated by comprehensive spectroscopic data analysis and electronic circular dichroism (ECD) calculations. Biological tests indicated that compound 5 displayed significant anti-tobacco mosaic virus (TMV) activity compared with the positive control ningnanmycin.
Polyethylene oxide (PEO)-based solid-state polymer electrolytes (SPEs) are limited by their poor cyclic stability and inferior ionic conductivity for applicating in high-safety, long-cycling and high-energy-density lithium metal batteries. Herein, porous boron nitride nanofibers (BNNFs) are filled into PEO-based SPE, which significantly suppresses Li dendrites growth and enhances the electrochemical performance of Li metal battery. BNNFs with high porosity have more active sites to connect with PEO, which can effectively reduce the crystallinity of the PEO matrix and enhance its ionic conductivity. Moreover, owing to the hardness and good stability of BNNFs, BNNFs/PEO/LiTFSI electrolyte exhibits a wider electrochemical window, better mechanical property and higher thermal stability compared with PEO/LiTFSI electrolyte. Consequently, the Li symmetric cell composed of 1% BNNFs/PEO/LiTFSI performs good cyclic stability (>1800 h), and the Li||1% BNNFs/PEO/LiTFSI||LFP full battery shows obviously improved performances in charge-discharge polarization voltage, discharge specific capacity, rate performance and cyclic stability than the Li||PEO/LiTFSI||LFP battery.
Molecular ferroelectrics have attracted much attention because of their excellent piezoelectricity, mechanical workability, and second harmonic effect. Here, we successfully prepared two molecular ferroelectrics 1,5–3.2.2-HdabcniX (X = ClO4−, 1; ReO4−, 2) by reactions of a quasi-spherical amine 1,5-diazabicycle[3.2.2]nonane (1.5–3.2.2-dabcn) with HX aqueous solution. Compounds 1 and 2 undergo high-temperature phase transitions at 381 K (1) and 396 K (2). Before and after the phase transition, they crystallize in the polar point group mm2, and the centrosymmetric point groups mmm and 4/mmm, respectively. According to Aizu rules, these two compounds experience mmmFmm2 and 4/mmmFmm2 type ferroelectric phase transitions, respectively. The ferroelectricity of both compounds is well expressed in their polycrystalline film at room temperature with low coercive voltages of 13 V for 1 and 25 V for 2. Using piezoelectric force microscopy (PFM), the 180° anti-parallel ferroelectric domains and the reversible polarization switching can be clearly observed in 1 and 2. This high-temperature molecular ferroelectric material has great application potential in flexible materials, biomechanics, intelligent wearables and other fields.
Hepatic ischemia-reperfusion injury (HIRI) is the cause of postoperative hepatic dysfunction and failure, and even death. As an important biological effector molecule, hydrogen sulfide (H2S) of mitochondria as a gasotransmitter that is usually used to protect against acute HIRI injury. However, the exact relationship between HIRI and mitochondrial H2S remains tangled due to the lack of an effective analytical method. Herein, we have fabricated a mitochondria-targeted H2S-activatable fluorogenic probe (Mito-GW) to explore the stability of mitochondrial H2S and track the changes of mitochondrial H2S during the HIRI. By virtue of pyridinium electropositivity and its amphiphilicity, Mito-GW could accumulate in mitochondria. It goes through an analyte-prompted immolation when reacts with H2S, resulting in the releasing of the fluorophore (GW). Therefore, the extent of Mito-GW conversion to GW can be used to evaluate the changes of mitochondrial H2S level in living cells and tissues. As proof-of-principle, we have used Mito-GW to demonstrate the mitochondria H2S-levels increase and then decrease during HIRI in vitro and in vivo. Our research highlights the tremendous potential of Mito-GW as a mitochondrial H2S fluorogenic probe in elucidating the pathogenesis of HIRI, providing a powerful tool for promoting future research on hepatology.
Exhaled ammonia (NH3) can be used as a crucial biomarker of kidney and liver diseases. However, the high humidity in the detection conditions remains a challenge for accurate detection by gas sensors. Herein, a copper-based metal-organic framework (CH3-Cu-BTC) with methyl (CH3-) functionalization of trimesic acid was synthesized for NH3 colorimetric sensing. The CH3-Cu-BTC exhibited a strong response for 5 ppm NH3 with high selectivity under high relative humidity (75% RH). Density functional theory (DFT) simulations indicated that the NH3 molecules interacted more strongly with CH3-Cu-BTC than H2O molecules did, and the corresponding color switching was attributed to the lone-pair electron in NH3 changing the coordination environment of Cu2+ ions, leading to an obviously visible color switching response from ruby green to blue. Based on the tailor-made pore chemistry, the precise detection of trace amounts of NH3 in exhaled air was realized through functionalized MOF materials. The strategy used in this study not only offers a new pathway for the rapid detection of low concentration NH3 under humid conditions, but also shows a method for early respiration diagnosis of kidney and liver diseases.
Introducing heavy halogen atoms into organic small molecules is a practical strategy for efficient singlet oxygen (1O2) generation. Generally, bromine or iodine atoms are introduced on the aza-boron-dipyrromethene (aza-BODIPY) core, rather than on the periphery aryl rings for efficient 1O2 generation. Herein, an aza-BODIPY dye NBDPBr with unexpected bromination on the periphery aryl rings was synthesized for photoacoustic (PA) imaging-guided synergistic photothermal therapy (PTT) and photodynamic therapy (PDT) in tumor cells. Owing to unexcepted bromination at the periphery aryl rings, NBDPBr demonstrated an outstanding singlet oxygen quantum yield of 66% which was superior to similar brominated photosensitizers previously reported. After encapsulation with amphiphilic polymer F-127, hydrophilic NBDPBr nanoparticles (NPs) were fabricated and exhibited an excellent photothermal conversion efficiency (η) of 43.0% under 660 nm photoirradiation. In vivo PA imaging results demonstrated that NBDPBr NPs could specifically accumulate at tumor sites and realized the maximum tumor retention at 7 h post-injection. All the in vitro and in vivo results indicated the significant potence of NBDPBr with unexpected bis-bromination for PA imaging-guided synergetic PDT/PTT.
The physicochemical properties of transition metal dichalcogenides (TMDs) are highly related to their structures and usually stable in air. However, under certain conditions they could be transformed into different structures due to oxidation. Considering this, various materials with fascinating structures have been explored by oxidation strategies, which possess novel properties and great potential in various applications such as solar batteries, hydrogen evolution reaction (HER) catalysts, and field effect transistors (FET). In this review, we systematically summarize the atomic structures of TMD oxidized variants and the corresponding fabrication approaches. Utilizing various characterization methods, the chemical components of TMD oxidized variants are illustrated. Furthermore, we expound the promising applications of the oxidized variants. This review is expected to provide a new insight for preparing precise materials at the atomic level through corresponding oxidation strategies.
Elevated level of hypochlorous acid (HClO) is closely associated with cancer development. Identifying HClO level in cancer cells would provide important evidence in either early-stage cancer diagnostics or monitoring of its treatment efficiency. In this work, a new pyronine-based fluorescent probe for rapid and sensitive detection of HClO was developed by condensing meso–formyl pyronine (PyCHO) with 2-hydrazinopyridine to form meso–pyridylhydrazone-functionalized pyronine PyHP, PyHP is nonfluorescent due to the excited-state C=N isomerization nonradiative decay, whereas the HClO-triggered formation of meso–triazolopyridyl pyronine PyTP abolishes the C=N isomerization and thus greatly enhances the fluorescence. With the probe, the cancer cells/tumor were distinguished with high-contrast from normal ones by laser confocal fluorescence imaging, and the tumor-to-normal (T/N) ratios obtained exceed the clinically acceptable threshold of 2.0. Moreover, its capability of in vivo imaging tumor was also demonstrated. These results indicate the potential of PyHP as an effective tool in the early clinical diagnosis of cancers.
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