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Reducing sulfur poisoning is significant for maintaining the catalytic efficiency and durability of heterogeneous catalysts. We screened PdAu nanoclusters with specific Pd : Au ratios based on Monte Carlo simulations and then carried out density functional calculations to reveal how to reduce sulfur poisoning via alloying. Among various nanoclusters, the core-shell structure Pd13Au42 (Pd@Au) exhibits a low adsorption energy of SO2 (-0.67 eV), comparable with O2 (-0.45 eV) and lower than CO (-1.25 eV), thus avoiding sulfur poisoning during the CO catalytic oxidation. Fundamentally, the weak adsorption of SO2 originates from the negative d-band center of the shell and delocalized charge distribution near the Fermi level, due to the appropriate charge transfer from the core to shell. Core-shell nanoclusters with a different core (Ni, Cu, Ag, Pt) and a Pd@Au slab model were further constructed to validate and extend the results. These findings provide insights into designing core-shell catalysts to suppress sulfur poisoning while optimizing catalytic behaviors.

Revealing the catalytic oxidation mechanism of volatile organic compounds (VOCs) is insightful for the development of efficient catalysts. However, because of the complicated interactions and a lar...

As visible light photocatalysts, narrow bandgap semiconductors can effectively convert solar energy to chemical energy, exhibiting potential applications in alleviating energy shortage and environmental pollution. Cu2O hollow spheres with a narrow band gap and uniform hierarchical structures have been fabricated in a controlled way. The one-pot solvothermal method without any template is simple and facile. The morphologies, crystal structures, composition, specific surface areas, and optical and photoelectric properties of the products were analyzed by various techniques. The hollow and solid Cu2O spheres could be fabricated by controlling the reaction time, and a possible growth process of the Cu2O hollow spheres was revealed. The degradation of methyl orange (MO) was used to investigate the visible-light catalytic properties of the Cu2O samples. More than 90% of MO is degraded under visible light illumination of 20 min, exhibiting a quick catalytic reaction. The rate constant of the Cu2O hollow spheres was 2.54 times and 46.6 times larger than those of the Cu2O solid spheres and commercial Cu2O powder, respectively. The possible photocatalytic mechanism of MO was revealed over Cu2O hollow spheres through the detection of active species. The as-prepared Cu2O hollow spheres display improved visible-light catalytic activity and stability, indicating their potential application in wastewater treatment.

Te-doped Li4Ti5O12 (LTO) was prepared by a ball milling-assisted solid-state method in air. The as-prepared powders were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and electrochemical impedance spectroscopy. Li4Ti4.95Te0.05O12 powder sintered at 850 °C presented improved ionic and electronic conductivities of 2.20×10-7 S·cm-1 and 2.40×10-9 S·cm-1 at room temperature, respectively, an order of magnitude higher than those of intrinsic LTO. Electrochemical analysis showed that the discharge specific capacities of Li4Ti4.95Te0.05O12 in Li half cells at 1 C and 5 C were 162.49 mAh·g-1 and 143.5 mAh·g-1, respectively, with capacity retention rates of 98.8% and 98.2% after 100 cycles. The Li4Ti4.95Te0.05O12/LiNi0.5Mn0.3Co0.2O2 full cells also showed a good specific capacity of 101.8 mAh·g-1 at 1 C and delivered good temperature adaptability. This study provides an effective strategy for the preparation of high-performance LTO anodes for lithium-ion batteries.

Biochar is increasingly used as a low-cost and effective adsorbent for heavy metals in wastewater. Herein, biochar pyrolyzed from rice straw was employed as an adsorbent for the removal of Th(IV) f...

Herein, we used biochar pyrolyzed from rice straw to adsorb uranium (U) from aqueous solutions. The adsorption of U(VI) on biochar was strongly dependent on pH but independent on ionic strength. HA/FA enhanced the sorption at pH 6.8. The sorption reached equilibrium within 3 h, which was not mediated by pH. The adsorption process was spontaneous and endothermic, and enhanced at higher temperature. However, the influence of temperature was negligible at low initial U(VI) concentrations. Therefore, biochar derived from rice straw may be a promising adsorbent for the removal of U(VI).

The development of high efficient oxide catalyst is crucial to remove the aromatics pollutants. Herein, we propose a ternary mullite SmMn2O5 to catalytically oxidize benzene and toluene at a low temperature. Through a joint exploration of experimental characterizations and density functional theory calculations, the active species on the surface of the material are accessed. In the presence of the two-coordinated surface labile oxygen (Olab), the hydrothermal-synthesized mullite achieves a remarkable deep oxidation performance with T90 at 223 °C (benzene) and 228 °C (toluene), superior to most reported oxide catalysts. Simultaneously, SmMn2O5 displays no deactivation after 150 h reactions with repeating water vapor. Combining in situ DRIFTS and DFT calculations, the dissociation of maleic anhydride into acetic anhydride species on Olab active sites turns out to be the rate-controlled step with a calculated kinetic barrier of 1.253 eV. These findings of Olab allow to understand the catalytic oxidation of metal oxides at the atomic level and are thus imperative for the catalyst development.

Electrochemical properties of alkali ions (Li+, Na+, and K+) intercalating into FeSe have been studied based on first-principles calculations within density functional theory. The intercalation sites of lithium ions are found to be different from sodium and potassium ions due to the small ionic radius of lithium. Calculations of minimum energy path on the diffusions of Li+, Na+, and K+ in FeSe show that the activation energies for those alkali ions increase with their ionic radii. Lithium ions have a rather smaller diffusion barrier of about 0.20 eV, which leads to a bigger diffusion coefficient of about 6.3 × 10 - 6 cm 2 / s . We also show that FeSe has a flat discharging stage at about 1.0 V with lithium ions. These results indicate that XFe2Se2 (X = Li, Na, K) may be potential electrochemical active materials, especially for solid-state electrolyte and supercapacitors.

It remains challenging for pure-phase catalysts to achieve high performance during the electrochemical oxygen reduction reaction to overcome the sluggish kinetics without the assistance of extrinsic conditions. Herein, a series of pristine perovskites, i.e., AMnO3 (A = Ca, Sr, and Ba), are proposed with various octahedron stacking configurations to demonstrate the cooperative catalysis over SrMnO3 jointly explored by experiments and first-principles calculations. Comparing with the unitary stacking of coordination units in CaMnO3 or BaMnO3 , the intrinsic SrMnO3 with a mixture of corner-sharing and face-sharing octahedron stacking configurations demonstrates superior activity (Ehalf-wave = 0.81 V), and charge-discharge stability over 400 h without the voltage gap (≈0.8 V) increasing in zinc-air batteries. The theoretical study reveals that, on the SrMnO3 (110) surface, the active sites switch from coordinatively unsaturated atop Mn (*OO, *OOH) to Mn-Mn bridge (*O, *OH). Therefore, the intrinsic dual coordination environments of Mn-Ocorner and Mn-Oface enable cooperative modulation of the interaction strength of the oxygen intermediates with the surface, inducing the decrease of the *OH desorption energy (rate-limiting step) unrestricted by scaling relationships with the overpotential of ≈0.28 V. This finding provides insights into catalyst design through screening intrinsic structures with multiple coordination unit stacking configurations.

Mn-based mullite catalyst GdMn2O5 is developed via the hydrothermal method to efficiently remove volatile organic compound acetone with a high efficiency and stability in total oxidation. The T90 over GdMn2O5 approaches to 160 s°C in contrast to 191 °C over 1 wt % Pt/Al2O3. The catalytic performance maintains after reaction at 200 °C for 260 h with 5.0 % H2O. The surface labile oxygen is the key to superior catalytic performance. According to the in situ DRIFTS and the oxidation pathway proposed by DFT calculations, the acetate species decomposition is assigned as the rate-limiting step. And the calculated kinetic barrier for the rate-limiting step, 151.7 kJ/mol (1.58 eV), is in line with the apparent activation energy from acetone oxidation over GdMn2O5 of 150.0 kJ/mol (1.56 eV). This work provides insights into developing highly efficient and hydrothermally stable volatile organic compounds removal catalysts via surface oxygen activation.

Monoclinic bismuth vanadium oxide (BiVO 4 ) hierarchical microtubes self-assembled by several nanowires have been successfully fabricated by a template-free approach. The morphology and structure of the as-prepared sample were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and UV–vis spectroscopy. BiVO 4 microtubes have monoclinic structure with energy band gap of 2.36 eV. Based on the time-dependent experiments, the possible formation mechanism of BiVO 4 microtubes was proposed. In addition, the photocatalytic activity of the as-prepared BiVO 4 samples was evaluated by the degradation of methyl orange (MO) and various reactive dyes (RDs) under xenon lamp irradiation. In comparison with BiVO 4 microrods, BiVO 4 microtubes with hollow and porous structures showed higher photocatalytic activities and universality under visible-light irradiation. Due to the unique hierarchical hollow structures contributing to the increase of photocatalytic activities, BiVO 4 microtubes exhibited the potential application as the promising visible-light photocatalyst.

A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine bosutinib in mice plasma and tissue using diazepam as the internal standard (IS). Sample preparation was accomplished through a protein precipitation procedure with acetonitrile. The analyte and IS were separated on an Acquity UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with the mobile phase of acetonitrile and 0.1% formic acid in water with gradient elution at a flow rate of 0.40 mL min−1. The detection was performed on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization (ESI) by multiple reaction monitoring (MRM) of the transitions at m/z 530.3 → 141.1 for bosutinib and m/z 285.2 → 193.1 for the IS. The linearity of this method was found to be within the concentration range of 5–3000 ng mL−1 with a lower limit of quantification of 5.0 ng mL−1. Only 3.0 min was needed for an analytical run. The method herein described was superior to previous methods and was successfully applied to the pharmacokinetic and tissue distribution study of bosutinib in mice after oral administration.

A broad number of natural and synthetic progestins are widely used in human and veterinary therapies. Although progestins exhibit adverse effects in aquatic organisms, information about environmental occurrence and fate have been limited to several compounds, hampering the accuracy of risk assessments of the compounds. In this study, a selective and sensitive analytical method was established to simultaneously determine 19 natural and 42 synthetic progestins in environmental waters, and the synthetic progestins included 19-nortestosterone, 17α-hydroxyprogesterone and progesterone derivatives. All of the target compounds were effectively separated using an HSS T3 column, and the recoveries for effluent and river samples were 80-115% and 75-105%, respectively. The detection limits for the 61 analytes were in the range of 0.05-0.60 ng/L and 0.03-0.40 ng/L for the effluent and river samples, respectively. The developed method is applied to analyze the target progestogens in sewage effluent and river water samples from Beijing. The detected concentrations of natural progesterone metabolites (3α-hydroxy-5β-tetrahydroprogesterone) were up to 63 times higher than those of the parent compound. Of the three groups of synthetic progestins, the progesterone derivatives were detected for the first time and had the highest concentrations followed by the 19-nortestosterone and 17α-hydroxyprogesterone derivatives. In contrast to previous studies, the predominant derivative compounds of 19-nortestosterone were found to be 19-nortestosterone, gestodene and mifepristone, and those of 17α-hydroxyprogesterone were 6-epi-medroxy progesterone 17-acetate and melengestrol acetate. The toxicities and environmental risk of these emerging progestins deserves more attention in the future.

Crystalline nanoporous CeO 2 (CM-CeO 2 ) has been successfully prepared through self assembly of poly 4-vinylpyridine (P4VP) template with Ce(NO 3 ) 3 ·6H 2 O precursor based on their strong acid–base interactions under high temperature (180 °C) hydrothermal conditions. After calcination of the sample at 550 °C in the air, crystalline nanoporous CeO 2 with opened nanopores was obtained. Pd nanoparticles acted as active species could be easily introduced into the sample, which gives the sample of CM-CeO 2 -Pd-1.0 (where 1.0 stands for weight percentage of Pd). CM-CeO 2 -Pd-1.0 exhibits very good catalytic activity (Conv. 82.1%) and selectivity (97.6%) for aerobic oxidation of benzyl alcohol under solvent-free conditions. The enhanced catalytic performance of CM-CeO 2 -Pd-1.0 should be attributed to synergistic effects between abundant nanopores, unique oxygen storage and release properties of CM-CeO 2 support. The preparation of CM-CeO 2 -Pd-1.0 may help develop cost-effective and efficient catalysts for aerobic oxidation of various alcohols into useful fine chemicals under mild conditions.

III-V interface with high-k oxide, especially HfO2, is crucial to the development of high mobility microelectronic devices. In this work, we systematically investigated the wurtzite GaN/cubic HfO2 interface based on the first-principles calculations with density functional theory in terms of the geometric structure and electronic properties. In order to mimic the high-k growth conditions, the interfacial oxygen contents in the slab interface models varied to study the interface stability and the relevant electronic structures. It is found that the oxygen rich interface, i.e., oxygen content of 83.3% (O5), shows the most stability in a large range of the oxygen chemical potential from 0 eV to −4.34 eV. Through the calculations of local density of states and Bader charge analysis, we noticed that increasing the interfacial oxygen content leads to the increase of the valence band offset (VBO) and the decrease of the conduction band offset (CBO), respectively. More importantly, interface O5 displays a promising VBO (0.86 eV) and CBO (1.34 eV), which meets the industrial requirements to confine the carrier in the III-V channel materials. Furthermore, no interfacial gap states are observed in interface O5, indicating that O5 is free of Fermi level pinning. This theoretical exploration suggests that varying oxygen content at the interface could result in the optimal interface for the applications of high mobility electronic devices.

In this article, we report the obtention of sphere-like copper sulfide (CuS) microcrystals with 3–5 μm diameter on a large scale by the solvothermal approach, which is simple, facile, and effective. The as-prepared products are well characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD), indicating that the sphere-like CuS microcrystals are composed of nanosheets with the uniform thickness of about 50 nm and have good morphology and high purity. The factors influencing the formation of the sphere-like CuS microcrystals are investigated in detail using SEM characterizations. Specially adjusting the quantity of thiourea can effectively control the formation of the flower-like, sphere-like, or irregularly spindle-like CuS microcrystals built by nanosheets. Based on the “oriented attachment mechanism,” CuS nanosheets are aligned with one another and point toward the spherical center, and further construct the sphere-like CuS microcrystals. The electrocatalytic oxidation of glucose in alkaline medium at the sphere-like CuS microcrystal-modified electrode has been monitored by cyclic voltammograms (CVs). Compared to the bare glassy carbon electrode, a couple of obvious redox peaks and the improved peak currents toward the glucose redox are examined at the sphere-like CuS sensor with the sensitivity of 117.3 μA cm−2 mM−1. The high electrochemical activity, good repetition, and stability indicate that the sphere-like CuS sensor has the potential application in the nonenzymatic glucose sensor.

The potential application of the hybrid phosphorene/graphene (P/G) composites as an anode material in Na-ion batteries (NIBs) has been explored based on first-principles calculations. The calculated elastic constants reveal that the P/G has an ultrahigh stiffness, which can effectively suppress the undesirable structural deformation during the sodiation and desodiation cycles. Na atoms can strongly bind with the phosphorene single-layer (SP), double-layer (DP), and their composites with graphene (SP/G, DP/G, G/DP/G), and can even cause a sliding between the layers when the DP/G accommodate more Na atoms. The migration of Na in P/G is anisotropic with the minimum energy path along the zigzag channel. The low diffusion barriers of only about several tens of meV ensure the high mobility of Na within the layers, and thus lead to rapid charge/discharge capacity of P/G. The electronic structures show that the hybrid P/G becomes metallic with the Na incorporation, which contributes to the good electric conductivity in P/G. We further demonstrate that the average open circuit voltage (OCV) of DP/G is 0.53 V, which is comparable to other anode materials. These results suggest that P/G composites hold great potential to be a good anode material in NIBs.

Various copper hierarchical structures assisted by surfactants were successfully fabricated combined with the electrodeposition technique. To the best of our knowledge, it is the first report on the controlled synthesis of metal copper hierarchical structures. All of the products synthesized in the presence and absence of surfactants, such as cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), or polyvinylpyrrolidone (PVP), were face-centered cubic copper, characterized by X-ray diffraction (XRD), indicating the surfactant-independent crystal structure. However, supplementing surfactants is helpful to construct hierarchical structures and exerts an important influence on copper morphologies. The absence of surfactants led to the formation of the nubby structures, while the use of surfactants resulted in the synthesis of the flower, dendrite, and sphere-like hierarchical morphologies. The effect of deposition time on the copper morphologies was investigated by scanning electron microscopy (SEM), and the possible formation mechanism of the copper hierarchical structures with various morphologies was discussed.