Latest ArticlesReverse water gas shift (RWGS) reaction is a crucial process in CO2 utilization. Herein, Ni- and NiCe-containing hexagonal mesoporous silica (Ni-HMS and NiCe-HMS) catalysts were synthesized using an in-situ one-pot method and applied for RWGS reaction. At certain reaction temperatures 500-750 ℃, Ni-HMS samples displayed a higher selectivity to the preferable CO than that of conventionally impregnated Ni/HMS catalyst. This could be originated from the smaller NiO nanoparticles over Ni-HMS catalyst. NiCe-HMS exhibited higher activity compared to Ni-HMS. The catalysts were characterized by means of TEM, XPS, XRD, H2-TPR, CO2-TPD, EPR and N2 adsorption-desortion technology. It was found that introduction of Ce created high concentration of oxygen vacancies, served as the active site for activating CO2. Also, this work analyzed the effect of the H2/CO2 molar ratio on the best NiCe-HMS. When reaction gas H2/CO2 molar ratio was 4 significantly decreased the selectivity to CO at low temperature, but triggered a higher CO2 conversion which is close to the equilibrium.
Prostate cancer (PCa) is the second most commonly diagnosed cancer in men. The Rac1-GTP inhibitor NSC23766 has been shown to suppress PCa growth. However, these therapies have low tumor-targeting efficacy in vivo. Therefore, it is essential to produce a drug delivery system that specifically targets the tumor site. Herein, novel l-phenylalanine-based poly(ester amide) (Phe-PEA) polymers were synthesized and loaded with NSC23766 (NSC23766@8P6 NPs), which had a small particle size (162.3 ± 6.7 nm) and high NSC23766 loading (8.0% ± 1.1%) with a more rapid release of NSC23766 at pH 5.0. In vitro cellular uptake and cytotoxicity assays demonstrated that NSC23766@8P6 NPs were rapidly taken up by PC3 cells and showed significant effects of PCa cell proliferation inhibition and G2/M phase arrest. Furthermore, in vivo studies using PC3-bearing mice demonstrated that NSC23766@8P6 NPs delivered by intravenous injection not only increased the drug concentration with prolonged retention (96 h) at the tumor site, but also inhibited tumor growth and induced apoptosis. In conclusion, we have discovered that NSC23766@8P6 NPs can serve as a delivery system that targets the tumor site and is therefore a promising therapeutic approach for PCa treatment.
An organic-inorganic hybrid FeIII–PrIII-included 2-germano-20-tungstate [Pr(H2O)8]2H2[Fe4(H2O)4 (pca)4Ge2W20O72]•34H2O (Hpca = 2-pyridinecarboxylic acid) (1) was hydrothermally prepared. Its polyoxoanion comprises one tetra-FeIII incorporated [Fe4(H2O)4(pca)4Ge2W20O72]8- hybrid entity and two [Pr(H2O)8]3+ ornamental cations. The [Fe4(H2O)4(pca)4Ge2W20O72]8- 2-germano-20-tungstate entity can be regarded as an infrequent S-type [Ge2W20O72]16- cluster pocketed by four [Fe(H2O)(pca)]2+ cations. The S-type [Ge2W20O72]16- cluster could be imagined as condensation of two divacant Keggin [α-GeW10O37]10- segments by sharing two atoms. It is of interest is that carboxyl O and pyridine N atoms on pca ligands concurrently bind with Fe3+ cations in a five-membered heterocyclic fashion to increase the stability of the whole structure. Furthermore, the electrochemical biosensing properties of 1 as the modified electrode material have been investigated for detecting norepinephrine (NPP), showing a low detection limit of 3.25 µmol/L. This work not only enriches structures of heterometallic germanotungstates (GTs), but also expands applications of polyoxometalates (POMs) in the electrochemical biosensing field.
Plasmodium parasites causing malaria have developed resistance to most of the antimalarials in use, including the artemisinin-based combinations, which are the last line of defense against malaria. This necessitates the discovery of new targets and the development of novel antimalarials. Plasmodium falciparum alanyl aminopeptidase (PfA-M1) and leucyl aminopeptidase (PfA-M17) belong to the M1 and M17 family of metalloproteases respectively and play critical roles in the asexual erythrocytic stage of development. These enzymes have been suggested as potential antimalarial drug targets. Herein we describe the development of peptidomimetic hydroxamates as PfA-M1 and PfA-M17 dual inhibitors. Most of the compounds described in this study display inhibition at sub-micromolar range against the recombinant PfA-M1 and PfA-M17. More importantly, compound 26 not only exhibits potent malarial aminopeptidases inhibitory activities (PfA-M1 Ki = 0.11 ± 0.0002 µmol/L, PfA-M17 Ki = 0.05 ± 0.005 µmol/L), but also possesses remarkable selectivity over the mammalian counterpart (pAPN Ki = 17.24 ± 0.08 µmol/L), which endows 26 with strong inhibition of the malarial parasite growth and negligible cytotoxicity on human cell lines. Crystal structures of PfA-M1 at atomic resolution in complex with four different compounds including compound 26 establish the structural basis for their inhibitory activities. Notably, the terminal ureidobenzyl group of 26 explores the S2′ region where differences between the malarial and mammalian enzymes are apparent, which rationalizes the selectivity of 26. Together, our data provide important insights for the rational and structure-based design of selective and dual inhibitors of malarial aminopeptidases that will likely lead to novel chemotherapeutics for the treatment of malaria.
Developing transition metal oxides (TMOs) with high energy, power, and long cycle lifetime for electric energy storage devices remains a critical challenge to date. Herein, we demonstrate a facile method that enables in-situ transformation of nickel cobalt oxide nanowire arrays (NiCoO NWA) into hierarchical nanowire-nanosheet arrays (ac-NiCoO NWSA) for enhanced energy storage properties. More specifically, the method leads to formation of atomically thin nanosheets (only 2.0 nm) and creates abundant antisite defects and oxygen vacancies. Owing to these merits, the as-prepared ac-NiCoO NWSA electrode exhibits over five-fold higher specific capacity, superior rate capability (up to 100 A/g), and excellent cycling stability of 10, 000 cycles at 50 A/g in alkaline electrolyte compared to pristine NiCoO NWA. Density functional theory (DFT) simulations elucidate the electrochemical activity enhancement mechanism of the TMOs. Moreover, our method triggers similar structural reconstruction phenomenon on other TMOs including ZnCo-, CoMn- and ZnNiCo-oxides, proving the universality of the method. Our findings provide a general method towards simultaneously manipulating the micro-morphologies and defects of TMOs for advanced energy storage devices.
Improving the transfer hydrogenation of N-heteroarenes is of key importance for various industrial processes and remains a challenge so far. We reported here a microcapsule-pyrolysis strategy to quasi-continuous synthesis S, N co-doped carbon supported Co single atom catalysts (Co/SNC), which was used for transfer hydrogenation of quinoline with formic acid as the hydrogen donor. Given the unique geometric and electronic properties of the Co single atoms, the excellent catalytic activity, selectivity and stability were observed. Benefiting from the quasi-continuous synthesis method, the as-obtained catalysts provide a reference for the large-scale preparation of single atom catalysts without amplification effect. Highly catalytic performances and quasi-continuous preparation process, demonstrating a new and promising approach to rational design of atomically dispersed catalysts with maximum atomic efficiency in industrial.
Alcohol fuels oxidation plays a significant role in carbon sustainable cycling and high-performance catalyst with a strong anti-poisoning effect is desired. Herein, Pt-Ni alloy supported on the N-doped graphene aerogel synthesized by simple freeze-drying and annealing was demonstrated to have such catalytic ability for alcohol fuel oxidation. Pt-Ni alloy particles were found uniformly dispersed over the surface of 3D N-doped graphene aerogel. High anti-poisoning ability for CO-like intermediates oxidation was demonstrated by the CO-stripping experiment. The as-prepared catalyst was found to have outstanding catalytic performance for methanol and ethanol oxidation with high catalytic activity, stability and catalytic kinetics. Compared to the control samples, the improved catalytic ability could be due to the presence of oxophilic Ni species and the support effect of 3D N-doped graphene aerogel that combined multi-advantages of large surface area, facile mass transfer, and abundant defects.
Catalytic potential of carbon nanomaterials in peroxydisulfate (PDS) advanced oxidation systems for degradation of antibiotics remains poorly understood. This study revealed ordered mesoporous carbon (type CMK) acted as a superior catalyst for heterogeneous degradation of sulfadiazine (SDZ) in PDS system, with a first-order reaction kinetic constant (k) and total organic carbon (TOC) mineralization efficiency of 0.06 min-1 and 59.67% ± 3.4% within 60 min, respectively. CMK catalyzed PDS system exhibited high degradation efficiencies of five other sulfonamides and three other types of antibiotics, verifying the broad-degradation capacity of antibiotics. Under neutral pH conditions, the optimal catalytic parameters were an initial SDZ concentration of 44.0 mg/L, CMK dosage of 0.07 g/L, and PDS dosage of 5.44 mmol/L, respectively. X-ray photoelectron spectroscopy and Raman spectrum analysis confirmed that the defect structure at edge of CMK and oxygen-containing functional groups on surface of CMK were major active sites, contributing to the high catalytic activity. Free radical quenching analysis revealed that both SO4·- and ·OH were generated and participated in catalytic reaction. In addition, direct electron transfer by CMK to activate PDS also occurred, further promoting catalytic performance. Configuration of SDZ molecule was optimized using density functional theory, and the possible reaction sites in SDZ molecule were calculated using Fukui function. Combining ultra-high-performance liquid chromatography (UPLC)–mass spectrometry (MS)/MS analysis, three potential degradation pathways were proposed, including the direct removal of SO2 molecules, the 14S-17 N fracture, and the 19C-20 N and 19C-27 N cleavage of the SDZ molecule. The study demonstrated that ordered mesoporous carbon could work as a feasible catalytic material for PDS advanced oxidation during removal of antibiotics from wastewater.
Applying mixed oxygen ionic and electronic conducting (MIEC) oxides as the cathode offers a promising solution to enhance the performance of solid oxide fuel cells (SOFCs). However, the phase instability in CO2-containing air and sluggish oxygen reduction activity of MIEC cathodes remain a long-term challenge for optimizing the electrochemical performance of SOFCs. Herein, a heterovalent co-doping strategy is proposed to enhance the oxygen reduction activity and CO2 tolerance of SOFCs cathodes, which can be demonstrated by developing a novel BaCo0.6Fe0.4O3-δ (BCF)-based MIEC oxide, BaCo0.6Fe0.2Sn0.1Y0.1O3-δ (BCFSY). In addition to improving the stability of BCF-based perovskites, this strategy achieves an optimized balance of ionic mobility and oxygen vacancies due to the synergies between the effects of the co-dopants. Compared with single-doped materials, BCFSY exhibits improved CO2 tolerance and considerably higher ORR activity, which is reflected in a significantly lower polarization resistance of 0.15 Ω cm2 at 600 ℃. The results of this work provide an efficient tactic for designing electrode materials for SOFCs.
Supraparticles (SPs), such as assembly of inorganic components with organic, have made tremendous attention in biochemical analysis, which represents a novel but challenging research orientation. Herein, a single-SPs multifunctional fluorescent sensor array has been developed for high-throughput detection of heavy metal ions in biofluids, which is based on an inorganic/organic hybrid SPs consisting of carbon dots (CDs) and an easily available porphyrin [5, 10, 15, 20-tetra(4-carboxyphenyl)porphyrin (TCPP)]. TCPP can aggregate with the CDs to form the assembly (CDs/TCPP SPs) through the electrostatic and π-π stacking interaction. There are two independent and clearly separated fluorescence emission peaks at 470 and 668 nm in the resultant CDs/TCPP SPs under 380 nm excitation. As a proof-of concept design, F470, F668, F668/F470 of SPs are chosen as three sensor components to constitute our sensor array. With the addition of metal ions, three sensor components can generate different fluorescence response patterns for discriminating 11 heavy metal ions via principal component analysis (PCA). Additionally, thiols can readily capture Cu2+ to switch the fluorescence of CDs/TCPP initially altered by Cu2+. Hence, CDs/TCPP-Cu2+ ensemble is further demonstrated to be a powerful sensor array for pattern recognition of 7 thiols and even chiral recognition of cysteine enantiomers. This novel strategy avoids the tanglesome synthesis of multiple sensing probes and dedicates an innovative method for the facile establishment of tongue-mimic sensors, which would prospectively sprout more homologous assumptions to broaden its application toward more biosensing fields.