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• Mechanism of CO2 adsorption on biomass derived carbon was explained using DFT methods. • Building the relationship between nucleophilicity and adsorption capacity of biochar. • Carboxyl and diketone groups are the most active O-containing sites. • TG-MS experiments proved the effect of nucleophilicity group of biochar on CO 2 adsorption. CO 2 adsorption is an important issue for sustainable development today. In this study, zigzag edge and armchair edge cluster models containing oxygen-containing groups were established, and the interaction with CO 2 molecules was calculated based on Density functional theory. The results indicated that the carboxyl and diketone groups have the CO2 adsorption capacity. The relationship between CO 2 adsorption performance and nucleophilicity of O-containing groups was established. A subsequent TG-MS experiment also proved that the introduction of nucleophilic group can promote interaction between CO 2 and carbon surface. [ABSTRACT FROM AUTHOR]

[Display omitted] • The carbon quantum dot is employed as cocatalyst to boost the catalytic oxidative desulfurization of phosphotungstic acid ionic liquid. • The carbon quantum dot favors the activation of hydrogen peroxide. • The CQDs/C 18 PWIL-1 exhibits excellent desulfurization efficiency under ambient conditions, in which dibenzothiophene was completely removed within 30 min. SO x emission from fossil fuel combustion is an important reason for environmental pollution. Achieving deep removal of sulfur-containing compounds from the fuel is essential. Herein, by combining phosphotungstic acid (HPW) with ionic liquids (ILs) and incorporating carbon quantum dots (CQDs), a series of catalysts (CQD/C 18 PWIL-x) for oxidative desulfurization (ODS) are prepared. Experimental results reveal that the modification of ILs could facilitate full contact between the active site and the organic phase, and improve mass transfer in the oxidative desulfurization process. Moreover, the incorporation of CQDs can promote the utilization of hydrogen peroxide. The synergistic action of multiple components leads to better activation of hydrogen peroxide. Therefore, the CQDs/C 18 PWIL-1 exhibits excellent desulfurization efficiency under ambient conditions, in which dibenzothiophene was completely removed within 30 min. Meanwhile, as heterogeneous catalyst, CQDs/C 18 PWIL-1 shows excellent cycling stability. The direct incorporation of CQDs significantly improves the catalytic activity and provides a new inspiration for the application of CQDs to ODS processes. [ABSTRACT FROM AUTHOR]

Extraction of aromatic sulfur compounds from model oil using a temperature-responsive ionic liquid (IL) N-butyl-N-methylpiperidinium tetrachloroferrate ([C 4 mpip]FeCl 4 ) as extractant has been investigated. In the extractive desulfurization process, liquid–liquid equilibrium was obtained at 45 °C for 10 min. After the extraction system was cooled to room temperature, the IL returned to solid due to the reversible thermoregulated phase transition of the IL. Therefore, it was easy for separation of oil and solid [C 4 mpip]FeCl 4 . The extraction efficiency and Nernst partition coefficient ( K N ) could get to 45.5% and 2.92, respectively, after a single extraction of DBT. Some important factors, such as extraction temperature, the amount of IL, initial sulfur content, multiple extractions, reusability and the mutual solution were investigated. The extraction ability of different sulfur compounds followed the order DBT > BT > 4,6-DMDBT. Finally, the extraction mechanism was studied systematically with experimental and theoretical methods. Compared with the extraction abilities of another three ILs, [C 8 mpip]FeCl 4 , [C 12 mpip]FeCl 4 and [C 4 Py]FeCl 4 , the size and aromatic structure of cation may be two positive factors but not the main extraction mechanism. The coordination interaction between Fe atom of IL and S atom of DBT was confirmed by IR spectra and theoretical computation. [ABSTRACT FROM AUTHOR]

This study employed the DFT method to calculate the catalytic activity of various organic functional groups during phenol production on seaweed biochar. It also used machine learning to analyze the correlation between electronic structure parameters of different sites and their catalytic activity. Finally, it summarized the essential characteristics of the most active site. [Display omitted] • Establishing cluster models of algal biochar catalyst and its catalytic mechanisms for lignin upgrading using a DFT method. • Decision trees, random forests, gradient boosting, and extreme gradient boosting were used to establish prediction models. • The random forest method performs best in revealing catalyst reactivity. • Fukui function is an effective descriptor for evaluating the reaction activity of adsorption sites. With the continuous development of the industrialization process, the reserves of primary energy sources such as petroleum have sharply decreased. The development of efficient and economical catalysts is of great significance in promoting the rapid pyrolysis of biomass to produce high-quality liquid fuels and chemicals. In this study, density functional theory (DFT) and machine learning (ML) were used to explore the catalytic reaction mechanism of guaiacol pyrolysis over seaweed biochar catalyst. Models of algae biochar catalysts with oxygen-containing or nitrogen-containing functional groups were established, and the surface transformation mechanism of guaiacol over the biochar catalyst was calculated using DFT. Furthermore, four machine learning methods (decision tree (DT), random forest (RF), gradient boosting (GB), and extreme gradient boosting (XGBoost)) were used to establish a mathematical model based on catalyst characteristics for predicting key intermediate adsorption energy during catalysis reaction. The fitting results and performance analysis of each prediction model show that the RF method-trained model has the highest accuracy. Fukui function (f-) was proved as an effective descriptor to evaluate the reactivity of adsorbed sites. This study provides a pathway to developing more efficient biochar catalysts, which could lead to more sustainable and environmentally friendly energy solutions. [ABSTRACT FROM AUTHOR]

ZSM-5 supported cobalt tungstate catalyst (CoWO 4 /ZSM-5-DR) was prepared by a facile dissolution-regrowth strategy. The sulfur removal could reach 100% within 5h over the obtained CoWO 4 /ZSM-5-DR. [Display omitted] • CoWO 4 /ZSM-5-DR was prepared via a facile dissolution-regrowth strategy. • The surface structure was reconstructed including the morphology and the pore size. • Removal of DBT could reach 100 % by CoWO 4 /ZSM-5-DR within 5 h. • CoWO 4 /ZSM-5-DR showed superior cycling stability even after 6 cycles. • O 2 •− was deduced as the main active species for the conversion of DBT to DBTO 2. Compared with homogeneous catalysts, heterogeneous catalysts have greater separability and recyclable properties. Yet, the uneven distribution of active sites in the conventional synthetic method is a challenge. Herein, ZSM-5 supported cobalt tungstate catalyst (CoWO 4 /ZSM-5-DR) was prepared by a facile dissolution-regrowth strategy under mild conditions. In comparison to the supported CoWO 4 catalyst generated by impregnation, the catalyst demonstrated a higher desulfurization efficiency in oxidative desulfurization due to the surface structural reconstruction of ZSM-5 and the uniform dispersion of the active substances. The as-prepared CoWO 4 /ZSM-5-DR catalyst can achieve 100 % sulfur removal within 5 h, which exhibits good stability and a high removal rate even after 6 cycles. This work provides new insight into supported binary metal oxide catalysts with highly homogenous dispersion and effectivity. [ABSTRACT FROM AUTHOR]

It is of great importance to develop efficient catalysts to achieve sulfur removal in fuel, protecting the world against the pollution caused by sulfur oxides. Aiming that, polyoxometalates supported materials have been employed as a vital class of heterogeneous catalysts for oxidative desulfurization. In this study, a serial of magnetic polyoxometalates-based mesoporous silica hybrid materials were successfully prepared over a facile hydrothermal and impregnation method, and evaluated in fast oxidation of aromatic sulfur. These hybrid materials exhibited interesting feature of rapid separation by external magnets, and excellent desulfurization performance to refractory sulfur compounds (benzothiophene, 3-methylbenzothiphene, dibenzothiophene, 4-methyldibenzothiophene and 4,6-dimethyldibenzothiphene). Furthermore, the sulfur removal could still reach 94% after recycling for ten times, which could be potentially applied in industry production. [ABSTRACT FROM AUTHOR]

[Display omitted] Heterogeneous catalysts show superior separable and recyclable property in comparison with homogeneous catalysts. However, the conventional synthetic method faces the problem of uneven distribution of active sites. Here, a facile dissolution-regrowth strategy was developed to prepare hollow mesoporous silica nanospheres supported cobalt molybdate (CoMoO 4 /HMS) under mild conditions, simultaneously, CoMoO 4 was obtained in situ. The homogenous dispersion of the active species made the catalyst manifest an outstanding desulfurization efficiency in aerobic oxidative desulfurization compared with the supported single-metal oxides catalysts or supported CoMoO 4 catalyst prepared by wet impregnation. The removal efficiency of three sulfur-containing substances, such as dibenzothiophene, 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene, could reach 100% by 5 h with molecular oxygen as an oxidant. Besides, the sulfur removal of DBT almost did not reduce after at least 8 cycles under the optimal reaction conditions. Through electron spin resonance spectroscopy and radical quenching experiments, O 2 − was determined as the main active oxygen species for sulfur oxidation. This dissolution-regrowth strategy can be used to prepare a series of supported multi-metal oxides for various applications. [ABSTRACT FROM AUTHOR]