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Catalysis involving gold supported on metal oxides has undergone extensive examination. However, the nature of the catalytic site under actual reaction conditions and the role of the support continue to be vigorously debated. This study addresses these issues through experimental investigations and theoretical simulations. We explore a novel catalytic mechanism that employs dynamic single-atom catalysis for the hydrochlorination of acetylene. This catalytic mechanism occurs in defective ZrO2-supported Au–Zr single-atom alloys. Specifically, the dynamic single-atom catalysis is a result of the mobility of the gold cation, which is accelerated by Cl radicals and strongly couples with the abundant unsaturated surface sites of ZrO2in a synergistic manner. As a result, the Au electronic structure dynamically evolves, leading to a decrease in the addition reaction energy barrier. Notably, the Au cation can detach from the Au–Zr alloy structure to catalyze the hydrochlorination of acetylene near the Zr–Ov–Zr sites and then reintegrate back into the Au–Zr alloy structure upon completion of the reaction. This study underscores the significance of dynamic active sites under reaction conditions and their pivotal role in catalysis.

Spinel ferrites with magnetic properties have great potential for the decontamination of aqueous systems due to their ease of recycling by magnetic separation. Herein, the purpose is to enhance ZnFe2O4spinel properties in terms of magnetization and catalytic performance viaMn substitution into the crystal structure. Zn1−xMnxFe2O4(x= 0–1) nanoclusters were successfully synthesized viaan optimal hydrothermal process, in which additives (i.e., citric acid and ammonia) play key roles in inhibiting impurity phase formation viahomogenizing the distribution of metal ions and slowing down the reaction rate. At a Zn/Mn ratio of 1 : 3, the nanocluster Zn0.25Mn0.75Fe2O4(ZMF0.75) composed of nanoparticles with sizes ranging from 5 to 10 nm shows the highest saturation magnetization (Ms = 68 emu g−1, which is ∼5 times greater than that of ZnFe2O4) and the best catalytic performance, with >99% azoxystrobin (AZX) degradation in a Fenton-like system. Moreover, the findings unveiled that the balance of Zn and Fe occupation in the polyhedron centres in the spinel crystal is broken upon replacing Zn with Mn. In all probability, the Zn/Fe/Mn cross-occupation phenomenon is essential for enhancing the activity of Fe and Mn multivalent metal atoms. A plausible mechanism for the synergistic effect of multiple active sites in ZMF0.75on the formation of HO and HO2 radicals is proposed. This work proves that Mn-substituted ZnFe2O4could be an efficient heterogeneous Fenton-like catalyst for EOC decontamination in aqueous systems with ease for recycling viamagnetic separation.

Two-dimensional (2D) materials have been developed into various catalysts with high performance, but employing them for developing highly stable and active nonprecious hydrogen evolution reaction (HER) catalysts still encounters many challenges. To this end, the machine learning (ML) screening of HER catalysts is accelerated by using genetic programming (GP) of symbolic transformers for various typical 2D MA2Z4materials. The values of the Gibbs free energy of hydrogen adsorption (ΔGH*) are accurately and rapidly predicted via extreme gradient boosting regression by using only simple GP-processed elemental features, with a low predictive root-mean-square error of 0.14 eV. With the analysis of ML and density functional theory (DFT) methods, it is found that various electronic structural properties of metal atoms and the p-band center of surface atoms play a crucial role in regulating the HER performance. Based on these findings, NbSi2N4and VSi2N4are discovered to be active catalysts with thermodynamical and dynamical stability as ΔGH*approaches to zero (−0.041 and 0.024 eV). In addition, DFT calculations reveal that these catalysts also exhibit good deuterium evolution reaction (DER) performance. Overall, a multistep workflow is developed through ML models combined with DFT calculations for efficiently screening the potential HER and DER catalysts from 2D materials with the same crystal prototype, which is believed to have significant contribution to catalyst design and fabrication.

The activation of HCl by cationic Au in the presence of C2H2is important for the construction of active Au sites and in acetylene hydrochlorination. Here, we report a strategy for activating HCl by the Au-based supported ionic liquid phase (Au–SILP) technology with the [N(CN)2−] anion. This strategy enables HCl to accept electrons from [N(CN)2−] anions in Au–[N(CN)2−] complexes rather than from pure [Bmim][N(CN)2], leading to notable improvement in both the reaction path and the stability of the catalyst without changing the reaction triggered by acetylene adsorption. Furthermore, the induction period of the Au–SILP catalyst was shown to be absent in the reaction process due to the high Au(III) content in the Au(III)/Au(I) site and the high substrate diffusion rate in the ionic liquid layer. This work provides a facile method to improve the stability of Au-based catalysts for acetylene hydrochlorination.

ABSTRACTThermochemical processes are considered as a promising technology for sewage sludge management, which could achieve volume reduction, energy and resource recovery, and effective destruction of pathogens. However, there are still many technology limitations and challenges of the thermochemical processes toward industrialization and commercialization. This review first briefly discusses the impact of sewage sludge on environmental sustainability and its current treatment and disposal methods. Typical thermochemical conversion technologies i.e., incineration/combustion, pyrolysis, gasification, and hydrothermal liquefaction for energy and resource recovery from sewage sludge are then comprehensively summarized. Subsequently, the technical challenges of thermochemical conversion of sewage sludge and the solutions that have been and/or are being developed to address the challenges are in-depth analyzed. Meanwhile, the prospects and future directions of the thermochemical technologies are outlined. In addition, the economic analysis and life cycle assessment of thermochemical conversion technologies are evaluated. Finally, the conclusions are put forward.

Ce-modified Mn–Fe mixed-oxide catalysts were prepared by a citric acid sol-gel method and characterized by X-ray diffraction, Raman, N2adsorption-desorption, infrared spectra, H2temperature-programmed reduction and thermogravimetric analyses. Their catalytic properties were investigated in ozone (O3) decomposition reaction. Results show that the small amount of rare earth metal Ce added during Mn–Fe (FM) mixed-oxide synthesis greatly improves the catalytic performance in O3decomposition. Among the prepared catalysts, the C0.04(FM)0.96mixed-oxide catalyst exhibits the highest catalytic activity and stability. The O3conversion over C0.04(FM)0.96is 98% after 24 h reaction at 25 °C under dry condition, and that over FM decreases to 90% after 16 h reaction. At 0 °C, the O3conversion over C0.04(FM)0.96is 95% after 7 h reaction under dry condition, and that over FM slows down to 70%. Under humid condition (RH = 65%), the O3conversion over C0.04(FM)0.96is 63% after 6.5 h reaction at 25 °C, while that over FM decreases to 55%. When Ce is doped into Mn–Fe mixed oxides, the small amount of Ce enters the crystal lattice of MnO2, and partial Fe is separated to form Fe2O3. This changes cause lattice distortion and increase defects and enable the as-synthesized Ce–Fe–Mn ternary mixed-oxide catalysts to acquire additional oxygen vacancies and increase their specific surface area, thereby increasing the number of reaction sites and enhancing the catalytic performance of the catalysts forO3decomposition.

To investigate the solubility of carbon dioxide (CO2) in geological fluids at different temperatures and pressures, we developed a method for measuring solubility using an optically transparent fused silica capillary cell as a high-pressure optical cell combined with Raman spectroscopy under geological sequestration conditions (temperatures of up to 353.15 K and pressure of up to 30.0 MPa). On the basis of the fact that the band intensity of an active Raman species is proportional to its concentration, we determined the linear correlation between the known CO2concentration and the ratio of the Raman peak heights of CO2to H2O (νCO2/νH2O) in homogeneous CO2–H2O and CO2–H2O–NaCl systems. Our results indicate that the Raman peak height ratio is a function of the CO2concentration and that the pressure and temperature do not significantly affect the relationship between the CO2concentration and νCO2/νH2Owithin the experimental P–T–xconditions. The νCO2/νH2Ovalues of the CO2-saturated solutions were determined by simulating the CO2geological sequestration T–P–xconditions. Then, the CO2solubilities were calculated using the linear relationship. Our results indicate that the method is feasible and that the solubility of CO2in H2O or NaCl solutions decreases with increasing temperature, increases with increasing pressure, and decreases with increasing salinity. On the basis of a comparison between our experimental data and the results of the previous model, our method provides satisfactory results.

A large amount of sulfuryl fluoride (SO2F2) is released into the atmosphere after fumigation, intensifying the greenhouse effect. Therefore, it is important to remove SO2F2generated in fumigation. In this study, the solubilities of SO2F2in 2-butoxyethyl acetate (BOEA), 3-methoxybutyl acetate (MOBA), 2-methoxyethyl acetate (MOEA), 1-methoxy-2-propyl acetate (MOPA), and 2-(2-ethoxyethoxy)ethyl acetate (DEOEA) were determined at T= (293.15 to 323.15) K and pressures up to about 600 kPa using the isochoric saturation method. Results showed that SO2F2solubility in the five acetate derivatives increased with increasing pressure and decreased with increasing temperature. The dissolution of SO2F2in these solvents belonged to a physical process. Furthermore, the Henry’s law constants and thermodynamic properties including standard Gibbs free energy, enthalpy, and entropy changes of SO2F2dissolution were further obtained. Compared with water, these five selected acetate derivatives showed potential application for SO2F2removal. Moreover, the solubilities of SO2F2in these solvents followed the order of MOBA > MOPA > BOEA > DEOEA > MOEA.

In the multifocus microscopic image measurement method, the distortion of the three-dimensional (3D) reconstruction model has always been an important factor affecting the measurement result. In spatial domains, the focus measure algorithm is based on the gradient change of the pixel point to determine the degree of focus of the pixel. So it will be difficult to accurately extract the focus of the pixel in the areas where color difference is not obvious, resulting in 3D model distortion. According to the optical principle, the high-frequency coefficients of the clear image are larger than the high-frequency coefficients of the blurred image. Based on this characteristic, this paper proposes a new multifocus microscopic image 3D reconstruction algorithm using a nonsubsampled wavelet transform (NSWT). The NSWT does not consider the downsampling in wavelet decomposition and has translational invariance. Therefore, the wavelet transform value of each pixel can be calculated in the image, so the high-frequency coefficient of each pixel can be obtained; then the convolution calculation is performed on the high-frequency coefficients of the pixel points in the fixed window as the focus measure value of the pixel point. Compared with the traditional algorithm, the algorithm proposed in this paper can show better unimodal and antinoise performance on the focusing measure curve. In this paper, the reconstruction of the experimental object is Alicona standard block triangular and semicylindrical. The proposed algorithm and the traditional algorithm for comprehensive measure use the root mean square error, peak signal to noise ratio, and correlation coefficient as the measure index. The experimental results and comparative analysis prove the correctness of the proposed algorithm and enable more accurate reconstruction of 3D models based on multifocus microscopic images.

The acidity and acid distribution of hierarchical porous ZSM-5 were tailored viaphosphate modification. The catalytic results showed that both benzene conversion and selectivity of toluene and xylene increased with the presence of appropriate amount of phosphorus. Meanwhile, side reactions such as methanol to olefins related with the formation of by-product ethylbenzene formation and isomerization of xylene to meta-xylene were suppressed efficiently. The acid strength and sites amount of Brönsted acid of the catalyst were crucial for improving benzene conversion and yield of xylene, whereas passivation of external surface acid sites played an important role in breaking thermodynamic equilibrium distribution of xylene isomers.

To investigate the volume expansion of a carbon dioxide (CO2) + n-hexane mixture at different temperatures and pressures, we developed a measurement setup using an optically transparent fused silica capillary cell (FSCC) combined with Raman spectra. The results showed that the method is feasible, the water seal is effective in its ability to avoid vaporization of n-hexane, and Raman spectra can help ensure the system equilibrium. The volume expansion factor of the CO2+ n-hexane mixture increased with increasing pressure from 1 to 10 MPa and decreased with increasing temperature from 30 to 80 °C. It was found that the trend of the expansion factor of the CO2+ n-hexane mixture was steeper at a higher temperature. When the temperature was 30 °C, the volume expansion factor increased from 2.15 to 13.61 as the pressure increased from 5.0 to 6.5 MPa. Meanwhile, the volume expansion factor increased from 2.36 to 19.40 as the pressure increased from 8.0 to 9.2 MPa at 60 °C. In addition, we obtained a significant and positive relationship between the volume expansion factor and the Raman peak height ratio of CO2and n-hexane using a quadratic equation.

The adsorption and diffusion of gas molecules in heterogeneous catalytic reactions are greatly influenced by various factors such as temperature, pressure, and catalyst microstructures. To clarify the role of controlling factors, the adsorption and diffusion behaviors of CO2and CO in the supported Pt system were investigated by multi-scale simulation. The adsorption number of molecules and adsorption energies calculated by molecular dynamics and density functional theory, respectively, indicate that Pt has a stronger adsorption for CO. The difference in the adsorption number is proportional to the number of adsorption sites and has a volcanic relationship with temperature. The diffusion coefficient of CO molecules varies more dramatically with temperature. Furthermore, the generalized formula related diffusion coefficient with temperature, pressure, and surface atom number of nanoparticles was further validated based on simulation data. This work provides insights into the diffusion modulation of gas molecules via the structural design of catalysts and regulation of reaction conditions.

Using high-valent Au(iii) catalysis is highly desirable in many reactions; however, it is plagued by the poor stability of Au(iii) complexes. Still, conventional catalysts need high Au content makes the high price and demand for Au is one of the major obstacles limiting their large-scale application. Here we demonstrate that stable and catalytically active Au(iii) complexes can be obtained using Supported Ionic Liquid Phase (SILP) technology. The resulting heterogeneous Au–IL/AC catalysts combine the advantages of the catalytic species being stabilised in the Au(iii) form by forming a Au(iii)–IL complex and the need for a less expensive metal catalyst because the active component can be better developed in a homogeneous reaction medium. When used in acetylene hydrochlorination reaction, this catalyst displayed an excellent specific activity and superior long-term stability. Under the same reaction conditions, the Au(iii)–IL/AC catalyst shows higher activity and stability towards the vinyl chloride monomer (VCM) than IL-free Au/AC (C2H2conversion = 72.1% at 180 °C compared to 16.1% without IL). It also delivered stable performance within the conversion of acetylene, reaching more than 99.4%, and there was only a 3.7% C2H2conversion loss after running for 300 h under the reaction conditions of a temperature of 180 °C and a C2H2hourly space velocity of 30 h−1. Its exceptional ability to maintain the high activity and stability further demonstrated the potential for the replacement of Hg-based catalysts for acetylene hydrochlorination.

Electrochemical reduction of nitric oxide (NO) to ammonia (NH3) remains a great challenge due to the difficulty of searching highly stable and active electrocatalysts. To this end, single metal atom-doped 2D MA2Z4(TM1/MA2Z4) materials were systematically studied through density functional theory (DFT) calculations. Cr1/HfSi2N4was screened out to be the ideal candidate from 15 TM1/MA2Z4in the NO reduction reaction (NORR), with the lowest limiting potential of 0.11 V along the A-A-O-H pathway compared to the other nine NORR pathways. From the analysis using the molecular orbital theory, the electronic structures reveal that the surface (Z element) and sublayer (A element) atoms play a crucial role in regulating the NORR performance with different NH2* adsorption configurations, respectively. Our calculations provide a new design strategy of single metal atom-doped catalysts for NO electrocatalytic conversion into NH3.

In the process of acetylene hydrochlorination, the rapid deactivation of supported gold (Au) catalysts by acetylene is still a huge challenge. Here, we provide an innovative strategy for constructing an acetylene–deficient reaction phase on the active site by coating an ionic liquid film on the Au(H2O)/C surface. The reactant ratio of C2H2to HCl in this acetylene–deficient reaction phase is 1:132, in contrast to the 1:1 M ratio in the gas phase, thus boosting the catalytic stability of Au(H2O)/C catalysts. The kinetic and theoretical analysis showed that the reduction of cationic gold by C2H2and the generation of carbon deposition can be inhibited in this constructed reaction phase during reaction. The current work not only broadens the scope of supported Au catalysts in acetylene hydrochlorination, but also verifies the perspective of the tunability of stoichiometric balance, which can be used in other catalytic applications.

Depth from focus (DFF) is a technique for estimating the depth and three-dimensional (3D) shape of an object from a multi-focus image sequence. At present, focus evaluation algorithms based on DFF technology will always cause inaccuracies in deep map recovery from image focus. There are two main reasons behind this issue. The first is that the window size of the focus evaluation operator has been fixed. Therefore, for some pixels, enough neighbor information cannot be covered in a fixed window and is easily disturbed by noise, which results in distortion of the model. For other pixels, the fixed window is too large, which increases the computational burden. The second is the level of difficulty to get the full focus pixels, even though the focus evaluation calculation in the actual calculation process has been completed. In order to overcome these problems, an adaptive window iteration algorithm is proposed to enhance image focus for accurate depth estimation. This algorithm will automatically adjust the window size based on gray differences in a window that aims to solve the fixed window problem. Besides that, it will also iterate evaluation values to enhance the focus evaluation of each pixel. Comparative analysis of the evaluation indicators and model quality has shown the effectiveness of the proposed adaptive window iteration algorithm.