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The combustion characteristics and kinetic properties of three antibiotic residues and their mixtures with coal were studied by thermogravimetric-differential scanning calorimetry (TG-DSC), and the kinetic mechanism functions were calculated.

During the past decade, deep eutectic solvents (DESs), emerging as green, versatile and adjustable alternatives to traditional solvents, have attracted intensive interests and immense research in various research fields. Especially DESs show quite a remarkable potential dissolving capability, due to their ability to donate as well as accept protons and electrons. A thorough and deep understanding of the microstructure, interactions and dissolving mechanism within DESs plays a key role in acquiring a task-specific DES. Quantum chemistry (QC) calculations provide structure-property-function relationship based on the molecular description and make up for the limitations of the current experimental techniques, showing promises for DESs screening and design. This paper summarizes the current research involving QC calculations and combined experiments, on investigating the structure, physicochemical properties and dissolving capability of DESs from the macroscopic and microcosmic perspective. This paper highlights and discusses the dissolving mechanism of various compounds in DESs, covering the recent successes in applying QC calculations to select the appropriate DESs as dissolving media. Furthermore, a brief analysis of perspectives and challenges for the future research in this field is presented. It is expected that this paper will inspire the future development of DESs from synthesis design to various designated applications.

Chlorinated benzene-containing compound (CBC) refers to a kind of volatile organic compound that contains benzene-ring and Cl atoms simultaneously, it has been widely concerned for the serious harm to human...

The novel La–B–O–C composites were fabricated as catalysts for methane catalytic combustion at low temperature, and considering the effect of newly C–O bond on B-site ions as active sites, three metal ions (Co, Mn, Fe) were selected for experiment. XRD, N2-physisorption, XPS and H2-TPR measurements were used to characterize the physicochemical properties of catalysts, which showed that the newly established C–O–B bond reduced the ionic valence of the B-site, and the redox capacities were increased or decreased to different degrees, respectively. Catalytic tests showed that T50 of La–Co–C–O composites (LC-C) and La–Fe–C–O composites (LF-C) are 377 °C and 482 °C, much lower than that of unmodified catalyst, respectively. But T50 of La–Mn–C–O composites (LM-C) increases to 507 °C from 493 °C. The superior performance of LC-C could be attributed to the high oxygen vacancies and enhanced redox property, and the better performance of LF-C was mainly benefited from the increase in lattice oxygen. For LM-C, the sacrifice of Mn4+ weakened the catalytic activity. There are more obvious mechanistic differences for different B-site elements in the La–B–O–C. The study will bring innovative insights into the design of excellent composites catalysts for methane oxidation.

Magnesia modified LaCoO3 was prepared by a facile one-step sol-gel method and used for removal of dilute methane. Compared with the conventional doping technique, the obtained LaCoO3@MgO-x exhibits pseudo core-shell structure and shows superior catalytic activity. The methane conversion exceeds 90% at 532 °C on LaCoO3@MgO-0.1, while only 60% of methane is conversed using the doped perovskite LaCo0.9Mg0.1O3. The high catalytic performance of LaCoO3@MgO-0.1 is mainly attributed to the adjustment of surface acid-base properties by the MgO shell structure. According to density functional theory (DFT) calculation, the methane is more likely to be adsorbed and cracked on LaCoO3@MgO-0.1. The in situ DRIFTS shows that CH3–O–CH3 intermediate specie is formed. The pseudo core-shell structure also enhances the stability and the LaCoO3@MgO-0.1 maintains high activity after working for 100 h. The above results demonstrate that surface modification by magnesia is an effective strategy for improving LaCoO3 catalytic performance.

Pure LaCoO3 and LaMnO3 were synthesized under different ion concentrations of precursors and the difference of active sites for CH4 oxidation between them was found. As the ion concentration of precursors increased, the two kind of perovskite crystals grew larger along with agglomerate. Meanwhile, LaCoO3 and LaMnO3 prepared by high ion concentrations of precursors enriched more surface Co3+ or Mn4+. The catalytic activity of the catalysts was tested in the oxidation reaction of methane under fuel-lean condition, results showed that LC-1.0 and LM-2.0 had the optimal activity and the light-off temperatures were 492°C and 486°C, respectively. Combining the physical and chemical characterization, the LaCoO3 and LaMnO3 possess different active sites for the methane catalytic reaction, and the conclusion was further verified by the DFT simulation. For LaCoO3, the surface lattice oxygen is the main active site, while for LaMnO3, the reaction is facilitated by the high-valent manganese.

The controlled oxidation of alcohols to the corresponding ketones or aldehydes via selective cleavage of the β-C-H bond of alcohols under mild conditions still remains a significant challenge. Although the metal/oxide interface is highly active and selective, the interfacial sites fall far behind the demand, due to the large and thick support. Herein, we successfully develop a unique Au-CuO Janus structure (average particle size=3.8 nm) with an ultrathin CuO layer (0.5 nm thickness) via a bimetal in situ activation and separation strategy. The resulting Au-CuO interfacial sites prominently enhance isopropanol adsorption and decrease the energy barrier of β-C-H bond scission from 1.44 to 0.01 eV due to the strong affinity between the O atom of CuO and the H atom of isopropanol, compared with Au sites alone, thereby achieving ultrahigh acetone selectivity (99.3 %) over 1.1 wt % AuCu

A novel La-Co-O-C (LC-C) composites were prepared via a facile co-hydrothermal route with oxides and glycerol and further optimized for methane catalytic activity and thermal stability via component regulation. It was demonstrated that Co

Trace Co

The environmental pollution of phenol-containing wastewater is an urgent problem with industrial development. Natural deep eutectic solvents provide an environmentally friendly alternation for the solvent extraction of phenol. This study synthesized a series of natural deep eutectic solvents with L-proline and decanoic acid as precursors, characterized by in situ infrared spectrometry, Fourier transform infrared spectrometry, hydrogen nuclear magnetic resonance spectrometry, and differential thermogravimetric analysis. Natural deep eutectic solvents have good thermal stability. The high-efficiency extraction of phenol from wastewater by natural deep eutectic solvents was investigated under mild conditions. The effects of natural deep eutectic solvents, phenol concentration, reaction temperature, and reaction time on phenol extraction were studied. The optimized extraction conditions of phenol with L-prolin/decanoic acid were as follows: molar ratio, 4.2:1, reaction time, 60 min, and temperature, 50 °C. Extraction efficiency was up to 62%. The number of extraction cycles can be up to 6, and extraction rate not less than 57%. The promising results demonstrate that natural deep eutectic solvents are efficient in the field of phenolic compound extraction in wastewater.

Volatile organic compounds (VOCs) are important precursors in the formation of ground-level ozone. In this study, the hourly mixing ratios of 61 ambient VOC species were monitored from 2018 till 2019 in 10 cities in the Beijing-Tianjin-Hebei (BTH) area of China, and the VOC distributions, speciation and photochemistry were also examined. The highest mixing ratios were found in the south, viz., Langfang (LF), Baoding (BD), Handan (HD) and Shijiazhuang (SJZ), and the lowest ones, in the north, viz., Chengde (CD) and Zhangjiakou (ZJK). In all of the cities, alkanes were the most abundant VOC component (50%), whereas ethane and propane were the most concentrated species. The mixing ratios of the VOCs exhibited a daily double peak as a result of the varying intensity of the photochemical reactions and the formation of the inversion layer. Additionally, the chemical reactivity of the VOCs was evaluated by calculating the loss rate of OH (LOH) for each species. Our results indicated that the alkenes and aromatics possessed higher LOH values as well as higher ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAp) values than the alkanes. Based on the diagnostic ratios of propane/n-butane, propane/i-butane, cis-2-butane/trans-2-butane, toluene/benzene and xylene/ethylbenzene, motor vehicle emissions contributed significantly to the ambient VOCs in the area.

Acid gases, especially sulfur dioxide (SO2), released from the burning of fossil fuels, have made a great contribution to environmental pollution. However, the technologies to remove the acid gases...

Manganese oxide supported Pt single atoms (Pt1/MnOx) are prepared by the molten salt method. Catalytic oxidation of toluene and iso-hexane, typical emissions from furniture paints industry, is tested. Pt1/MnOx shows poor and high catalytic stability for toluene and iso-hexane oxidation, respectively. Enhancement in the catalytic stability for toluene oxidation is observed after the hydrogen reduction treatment of Pt1/MnOx at 200 °C. The hydrogen treated catalyst possesses the weaker Mn–O bonds and lower coordination number of Pt O, with superior mobility of lattice oxygen and appropriate toluene adsorption. Balancing lattice oxygen mobility and volatile organic compounds adsorption is important for the catalytic stability of Pt1/MnOx. For the oxidation of toluene and iso-hexane mixture, owing to the competitive adsorption, iso-hexane oxidation is greatly inhibited, while toluene oxidation is not influenced. The present Pt1/MnOx catalyst holds promising prospect in furniture paints industry applications because of high catalytic stability and water resistance ability.

Methane is a greenhouse gas that contributes to global warming. Hence, effectively removing the low concentration (1000 ppm) of methane in the environment is an issue that deserves research in the field of catalysis. In this study, oxygen-magnesium bivacancies are simultaneously imbedded into MgO by designing an in situ reduction combustion atmosphere for oxygen release and substituting magnesium with carbon to induce the formation of magnesium vacancies. The DFT calculations reveal that the surface electron density of MgO is improved by the oxygen vacancy structure and the substitution of Mg by C in bulk; this accelerates migration of the charge from the material surface to the adsorbed oxygen species, which leads to abundant surface peroxide species that enable activation and oxidation of methane at a low temperature (below 200 °C). This work could provide a concept for developing non-noble or transition metal oxides for low-temperature activation and conversion of alkanes in the thermocatalytic field through reactive oxygen species.

CO

Balancing the NH3 selective catalytic reduction (NH3-SCR) and catalytic oxidation performance is difficult but necessary for the synergistic elimination of NOx and chlorine-containing volatile organic compounds (CVOCs). We herein unveiled that electronic structure tailoring of the applied catalyst was an efficient pathway for balancing the catalytic behaviors in the NH3-SCR of NO and chlorobenzene catalytic oxidation (CBCO). Specifically, environmentally friendly CeO2 substituted by low valent Al3+ exhibited better NH3-SCR of NO and CBCO activity in comparison with the CeO2 sample without doping. Detailed characterizations and theoretical simulations revealed that the strong dopant-oxide pairs in the CeO2 with Al3+ doping significantly tailored the electronic structure of O 2p states, enhancing the amount of Lewis acid sites and promoting the ability of lattice oxygen to act as an oxidizing agent, thereby leading to superior performance for the synergistic elimination of NO/CB. The counterpart with substitution of high valent Ta5+ showed an opposite trend, due to that Ta5+ donated more electrons to the coordination oxygen than Ce4+ inhibiting lattice oxygen separating from the surface of the catalyst, and Lewis base sites were formed.

To achieve efficient degradation of toluene, a series of Cu1-yMn2CeyOx/sepiolite catalysts (y = 0.1, 0.2, and 0.3) with different Cu1-yMn2CeyOx loadings (10%, 20%, and 30%) were prepared via the co-precipitation method. The structure-activity and surficial elemental species of Cu1-yMn2CeyOx/sepiolite were characterized by XRD, TEM, SEM, BET, ICP-MS and XPS. The catalytic activity of the catalysts was tested in the oxidation reaction of toluene, results showed that 20%Cu0.8Mn2Ce0.2Ox/sepiolite remains able to remove toluene completely with high efficiency at a temperature of 289 °C. Two kinetic models have been selected and tested to describe the oxidation of toluene, the Mars-van krevele (MVK) model provided a good fit (R2 ≥ 0.99). And the optimal relation of the surface oxidation activation energy (26.074 kJ mol−1) and surface reduction activation energy (23.591 kJ mol−1) were calculated.

In this work, Fe2O3 supported single atom Pt (x Pt1/Fe2O3, x = 0.25 and 0.5 wt%) catalysts (SACs) are synthesized via a novel and simple impregnation-pyrolysis method. HAADF-STEM images show that Pt is atomically dispersed on the surface of Fe2O3. All samples exhibit good light-thermal conversion efficiency, which can increase the surface temperature of catalysts to 210 °C. The 0.5 Pt1/Fe2O3 exhibits the best photothermal catalytic performance (the toluene conversion and CO2 yield are 95 % and 87 %, respectively) for toluene oxidation under the irradiation of simulated sunlight with light intensity of 720 mW/cm2, which is attributed to its good light-thermal conversion efficiency and low temperature reducibility. The Vis-IR light plays a critical role in the photothermal catalytic oxidation of toluene in the whole solar spectrum. Furthermore, the possible photothermal catalytic reaction pathway of toluene oxidation is proposed based on the TD-GC/MS and in-situ DRIFTS experiments.

In this paper, H2O2 was used to control the morphology of Ni-B nanoparticles prepared by chemical reduction of nickel ethylenediamine complex. With increasing H2O2 concentration, Ni-B nanoparticle morphology progressed from pompon-like to sea urchin-like and finally to a flower-like shape. The controlled morphology was the result of dynamic equilibrium between the reduction of nickel ions by KBH4 and oxidation dissolution of Ni-B nanoparticles due to etching by H2O2. Additionally, the Ni-B catalyst nanoparticles had large BET areas and more uniform Ni active centers on the surface. However, excess H2O2 could disrupt the dynamic equilibrium, allowing the production of various structures of Ni-B nanoparticles. The catalyst composition with a molar ratio of 1:1 Ni ion to H2O2 showed the best activity toward electrocatalytic oxidation of ethanol.

Spinel oxides, e.g., NiCo