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[Display omitted] • A novel type of PILs has been fabricated. • PILs integrate the permanent pores of porous solids with the exceptional properties of ILs. • PILs possess high activity and selectivity for the DBT oxidation. • IL moiety serves as an extractant to enrich DBT and creates an electrostatic solvent effect. • UiO-66 moiety serves as a catalysis to handily catalyze the ODS reaction. Developing a highly efficient strategy for the stabilization of the solid-liquid interface is a persistent pursuit for researchers. Herein, porous ionic liquids based on UiO-66 (Zr) porous materials were synthesized and applied to the selective desulfurization catalysis, which integrates the permanent pores of porous solids with the exceptional properties of ionic liquids. Results show that porous ionic liquids possess high activity and selectivity for dibenzothiophene. Experimental analysis and density functional theory calculations revealed that the ionic liquids moiety served as an extractant to enrich dibenzothiophene into the porous ionic liquids phase through the π···π and C H···π interactions. Additionally, the electrostatic solvent effect in the porous ionic liquids contributes to the stabilization solid-liquid interface, which was favorable for UiO-66 moiety to catalytically activate hydrogen peroxide (H 2 O 2) to generate ·OH radicals, and subsequently oxidized dibenzothiophene to the corresponding sulfone. It is hoped that the development of porous ionic liquids could pave a new route to the stabilization of the solid-liquid interface for catalytic oxidation. [ABSTRACT FROM AUTHOR]

With the increasingly strict limitations on emission standards of vehicles, deep desulfurization in fuel is indispensable for social development worldwide. In this study, a series of hybrid materials based on SiO2-supported polyoxometalate ionic liquid were successfully prepared via a facile ball milling method and employed as catalysts in the aerobic oxidative desulfurization process. The composition and structure of prepared samples were studied by various techniques, including FT-IR, UV-vis DRS, wide-angle XRD, BET, XPS, and SEM images. The experimental results indicated that the synthesized polyoxometalate ionic liquids were successfully loaded on SiO2 with a highly uniform dispersion. The prepared catalyst (C16PMoV/10SiO2) exhibited good desulfurization activity on different sulfur compounds. Moreover, the oxidation product and active species in the ODS process were respectively investigated via GC-MS and ESR analysis, indicating that the catalyst can activate oxygen to superoxide radicals during the reaction to convert DBT to its corresponding sulfone in the fuel. [ABSTRACT FROM AUTHOR]

Acidic deep eutectic solvents (DESs) have been considered desirable extractants and catalysts for desulfurization. However, their hydrogen bond donors (HBDs) are usually sole organic acids, which are not conducive to efficient green catalysis. Herein, a novel inorganic–organic dual-acid DES (DADES) was reported for efficient extractive and oxidative desulfurization. Benefiting from the physical interaction among the three components in a DADES, a transparent homogeneous liquid can be obtained even though inorganic acid (boric acid, BA) and organic acid (acetic acid, AA) can be immiscible. Furthermore, the dual-acid HBD can increase the acidity of the DADES and reduce its viscosity, accelerating its mass transfer efficiency and enhancing its catalytic activity. With 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) as the hydrogen bond acceptor, [Bmim]Cl/BA/0.3AA effectively activated hydrogen peroxide and achieved sulfur removal of 96.6% at 40 °C. Furthermore, the universality of the synergistic effect in various DADESs was confirmed by the modulation of the types of organic acids. This study not only motivates the construction of more intriguing novel DESs based on the DADES concept but also highlights their potential in clean fuel production. [ABSTRACT FROM AUTHOR]

The adsorptive desulfurization (ADS) technique is efficient to removal of sulfur compounds from fuels under mild conditions. The hexagonal boron nitride (h-BN) has been extensively applied in the ADS process as the adsorbent. To improve the adsorptive capacity and selectivity of BN material, the modification of the BN is necessary by doping heteroatoms. Herein, the rational design of the single transition metal (TM) atom (Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd) supported on the h-BN pristine and defective surface has been investigated by means of density functional theory. Our calculations revealed that both B-vacancy (VB) and N-vacancy (VN) of h-BN monolayer are good sites for anchoring the TM atoms. The adsorptions of dibenzothiophene and methylnaphthalene on the defective BN monolayer supporting TM are used to screen effective ADS adsorbents. Our results indicate Au/VN, Pt/VB, and Au/VB systems are suitable as the ADS adsorbents with excellent adsorption capacity and good selectivity for DBT. The charge analysis and reduced density gradient reveal that the superior selectivity will be ascribed to the formation of the S-TM bond coordination bond. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe single-atom adsorbents based on BNCO (Fe-BNCO) was synthesized. • Fe-BNCO-0.5 exhibits excellent adsortpin capacity for DBT (49.7 mg S/g). • Fe-doping results in a decrease of the crystallininty and a higher specific surface area. • The enhanced performance is sourced from the newly formed S-Fe coordination bond. Adsorbents with high adsorption capacity and selectivity have long been the pursuit of researchers in the field of adsorptive desulfurization. In this study, a novel single-atom adsorbent comprised of iron (Fe) integrated into C, O co-doped hexagonal boron nitride (Fe-BNCO) has been successfully synthesized. This unique material demonstrates outstanding adsorption capabilities, boasting an adsorption capacity of 49.7 mg S/g and excellent selectivity for adsorptive desulfurization. Notably, this adsorption capacity is 48.6 % higher than that of pure BNCO. The incorporation of the Fe element into boron nitride materials induces a reduction in crystallinity and an increase in specific surface area, resulting in a higher number of available adsorption sites. Combining experimental analysis with theoretical calculations, we propose that the exceptional adsorption performance of Fe-BNCO can be attributed to the formation of S-Fe coordination interaction, while maintaining the existing π-π interactions. This study advances our understanding of adsorbents with high adsorption capacity and selectivity, providing valuable insights for the field of adsorptive desulfurization. [ABSTRACT FROM AUTHOR]

Single atom adsorbents (SAAs) are a novel class of materials that have great potential in various fields, especially in the field of adsorptive desulfurization. However, it is still challenging to gain a fundamental understanding of the complicated behaviors on SAAs for adsorbing thiophenic compounds, such as 1-Benzothiophene (BT), Dibenzothiophene (DBT), and 4,6-Dimethyldibenzothiophene (4,6-DMDBT). Herein, we investigated the mechanisms of adsorptive desulfurization over a single Ag atom supported on defective hexagonal boron nitride nanosheets via density functional theory calculations. The Ag atom can be anchored onto three typical sites on the pristine h-BN, including the monoatomic defect vacancy (B-vacancy and N-vacancy) and the boron-nitrogen diatomic defect vacancy (B-N-divacancy). These three Ag-doped hexagonal boron nitride nanosheets all exhibit enhanced adsorption capacity for thiophenic compounds primarily by the S-Ag bond with π-π interaction maintaining. Furthermore, from the perspective of interaction energy, all three SAAs show a high selectivity to 4,6-DMDBT with the strong interaction energy (−33.9 kcal mol−1, −29.1 kcal mol−1, and −39.2 kcal mol−1, respectively). Notably, a little charge transfer demonstrated that the dominant driving force of such S-Ag bond is electrostatic interaction rather than coordination effect. These findings may shed light on the principles for modeling and designing high-performance and selective SAAs for adsorptive desulfurization. [ABSTRACT FROM AUTHOR]

Boron nitride (BN) is a two‐dimensional ceramic material that has been widely applied in various catalysis reactions. However, endowing the BN material with adequate reactive centers remains to be a considerable challenge. Herein, we propose a tunable boron and nitride dual vacancies strategy to generate highly active oxygen‐doping BN (BNO) material via heat treatment in vacuum. Experimental results indicate that the vacuum treatment fabricates boron and nitride dual vacancies on the BNO. The as‐prepared vacuum treated BNO (V‐BNO) was applied as the initiator to accelerate the aerobic oxidative desulfurization (ODS) of fuel. The boosted aerobic ODS system achieves 100 % sulfur removal in 6 h, and it can be recycled 6 times without any significant performance loss. Meanwhile, the density functional theory (DFT) reveals the reaction pathway on the V‐BNO, ensuring the contribution of boron and nitride dual vacancies to the initiation of the reaction. This work highlights the vital role of dual vacancies as initiating sites for the enhanced aerobic ODS. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs) have been intensively investigated as promising “green” solvents for a range of industrial processes, although most research continues to be focused on binary DESs. This paper reports on a class of ternary DESs formed by choline chloride (ChCl), polyethylene glycol (PEG), and boric acid (BA) that may be viewed as a new system for extraction and oxidative desulfurization (ODS) of diesel fuel. Compared with organic acid-based DESs, ternary DESs offer advantages including low volatility, low toxicity, and high activity. After tuning the molar ratio of the three compositions, sulfur removal reached 99.2% in 2 h at 60 °C when the molar ratio of H2O2 to dibenzothiophene was 6. The binary DESs, ChCl/PEG and ChCl/BA, showed unsatisfactory extraction and oxidation efficiency. The reaction mechanism identified through experimental and theoretical methods showed that superoxide radical may be the main active oxygen species, and BA-based peroxides may also play an important role. The results of this study may expand the use of BA and supply a new class of DESs for ODS and other possible applications. [ABSTRACT FROM AUTHOR]

Highlights • Sn based DESs with urea were firstly synthesized and introduced into hexagonal boron nitride. • Sn based DESs with urea were served as both reaction solvents and metal sources. • These materials present higher adsorption capacity for dibenzothiophene (DBT) from model oils. • The nature of the ADS source from the π-complexation and hydrogen bonding interaction between SnO 2 and DBT. Graphical abstract Sn based DESs with urea were firstly synthesized and introduced into hexagonal boron nitride. These materials present higher adsorption capacity for dibenzothiophene (DBT) from model oils. The nature of the ADS source from the π-complexation and hydrogen bonding interaction between SnO 2 and DBT. Abstract Adsorptive desulfurization (ADS) from fuels is considered as the most promising strategy due to the advantage of low energy consumption, to treat on sulfur which would induce serious air pollution. In this work, Sn-based DESs with urea were firstly synthesized and introduced into hexagonal boron nitride (h-BN) as both reaction solvents and metal sources. Adsorption experiments show that the as-prepared adsorbents present higher adsorption capacity for dibenzothiophene (DBT) from model oils as compared with the commercial BN. Especially, the Sn-BN-800 (SnO 2 supported BN with OH groups substitution at B sites) shows the highest performance. By combining experimental and theoretical analysis, we propose that the performance enhancement arises from the π-complexation and hydrogen bonding interaction between SnO 2 and DBT. In addition, the OH groups, which were substituted at the edge site of B, may also enhance the electron transfer from DBT to Sn-BN-800, leading to the improved adsorption capacity. [ABSTRACT FROM AUTHOR]

Generally, the high specific surface area of catalysts with a highly uniform dispersion of active centers is beneficial for the improvement of catalytic performance in a reaction. Herein, a kind of mesoporous molybdenum-silica hybrid materials was successfully prepared via one-pot calcination method using molybdenum-based poly (ionic liquids) as template and active metal sources, which was characterized in detail and evaluated in the oxidative desulfurization of organosulfur in fuel. The experimental results indicated that the prepared samples possessed not only high specific surface area, but also a highly uniform dispersion of active sites in the sample. Under mild operating condition, the typical sample (PILMo/Si-400) with a BET area of 597.6 m2/g can achieve the complete desulfurization in 30 min without any additional organic extractant. After recycling for seven times, the desulfurization for PILMo/Si-400 can still reach 100 %. In addition, the possible mechanism for oxidative desulfurization was discussed according to the radical trapping experiments. • Molybdenum-silica hybrid materials were successfully constructed from polyoxometalates-based poly (ionic liquids). • The prepared samples possessed high specific surface area with a uniform dispersion of active molybdenum species. • Deep oxidative desulfurization and recycling ability can be achieved in 30 min with no additional extractant. • The structure-activity relationship was investigated via various technologies. [ABSTRACT FROM AUTHOR]

Highlights • The activated BN samples with more surface active atoms show excellent adsorptive desulfurization performance. Abstract An activated boron nitride (BN) adsorbent was prepared via a facile rapid pyrolysis reaction. The as-prepared activated BN displayed unique atomic arrangements with short-range order and long-range disorder, which possessed more surface active atoms. It was found that activated BN adsorbent displayed an outstanding adsorptive desulfurization performance towards dibenzothiophene (DBT) (42.2 mgS g−1 adsorbent for the 500 ppm sulfur model oil), which was higher than that of graphene-like BN adsorbent (30.0 mgS g−1 adsorbent). Besides, the obtained activated BN adsorbent exhibited excellent selectivity and recyclability for removal of sulfur compound. These results demonstrated that activated BN is a desired adsorbent for adsorptive desulfurization and this strategy can be extended to the purposive preparation of other efficient adsorbents. Graphical abstract Image, graphical abstract The TEM images of activated BN and the adsorption capacities of activated BN. [ABSTRACT FROM AUTHOR]

Supported ionic liquid (IL) catalysts [Cnmim]3PMo12O40/Am TiO2 (amorphous TiO2) were synthesized through a one-step method for extraction coupled catalytic oxidative desulfurization (ECODS) system. Characterizations such as FTIR, DRS, wide-angle XRD, N2 adsorption-desorption and XPS were applied to analyze the morphology and Keggin structure of the catalysts. In ECODS with hydrogen peroxide as the oxidant, it was found that ILs with longer alkyl chains in the cationic moiety had a better effect on the removal of dibenzothiophene. The desulfurization could reach 100% under optimal conditions, and GC-MS analysis was employed to detect the oxidized product after the reaction. Factors affecting the desulfurization efficiencies were discussed, and a possible mechanism was proposed. In addition, cyclic experiments were also conducted to investigate the recyclability of the supported catalyst. The catalytic activity of [C16mim]3PMo12O40/Am TiO2 only dropped from 100% to 92.9% after ten cycles, demonstrating the good recycling performance of the catalyst and its potential industrial application. [ABSTRACT FROM AUTHOR]

With the aim of deep desulfurization, silica-supported polyoxometalate-based ionic liquids were successfully prepared by a one-pot hydrothermal process and employed in heterogeneous oxidative desulfurization of various sulfur compounds. The compositions and structures of the hybrid samples were characterized by various methods such as FT-IR, XPS, Raman, UV-Vis, wide-angle XRD and N2 adsorption-desorption. The experimental results indicated that the hybrid materials presented a high dispersion of tungsten species and excellent catalytic activity for the removal of 4,6-dimethyldibenzothiophene without any organic solvent as extractant, and the sulfur removal could reach 100.0% under mild conditions. The catalytic performance on various substrates was also investigated in detail. After cycling seven cycles, the sulfur removal of the heterogeneous system still reached 93.0%. The GC-MS analysis results demonstrated that the sulfur compound was first adsorbed by the catalyst and subsequently oxidized to its corresponding sulfone. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H 2 O 2 ) decomposition mechanism and its oxidative desulfurization activity on hexagonal boron nitride monolayer (h-BN) have been explored by density functional theory (DFT) at M06–2X/6-311 + G (d,p) level. A cluster model which contains seven rings has been constructed to simulate the h-BN surface. It is found that 7 possible species will be generated after the decomposition of H 2 O 2 . Among them, 2H*+O 2 * and 2H*+2O* are relatively unstable while other species, such as HOO*+H*, HO*+HO*, H*+HO + O*, H 2 O*+O* are relatively stable and may exist in the current system. In addition, 4 decomposition pathways have been explored. Results show that the H 2 O 2 * will first undergo an O-H bond break (HOO*+H*), then the HO-O bond decomposes into H*+HO*+O* (Pathway (b)). By considering the concentration and activation energy together, the H 2 O*+O* is proposed to be the most possible active species for oxidative desulfurization due to the relative higher concentration and lower activation energy. [ABSTRACT FROM AUTHOR]

A series of WO3/TiO2 catalysts with a pore structure were successfully synthesized. The catalysts were systematically characterized and it was found that different calcination temperatures had great effects on the pore structure of the catalysts. The catalyst presented a mesoporous structure after calcining at 550 °C (expressed as 550-WO3/TiO2) and had the largest specific surface area among the mesoporous catalysts. The oxidation of dibenzothiophene (DBT) with 550-WO3/TiO2 catalyst reached 100% under optimum conditions. After recycling for 6 times, the oxidation of DBT could still achieve a DBT removal of 96.7%, suggesting that the catalyst had good stability and recycle performance. In addition, DBT sulfone (DBTO2) was proven to be the only oxidation product of DBT after the reaction, as observed by the GC-MS analysis. The catalytic activities of the catalyst on different substrates were also investigated, and the activities decreased in the order: DBT ＞ 4-MDBT ＞ 4,6-DMDBT ＞ BT. [ABSTRACT FROM AUTHOR]

The selectivity for sulfur removal from oils is an important topic. In this work, the selectivity for different sulfur removal methods has been studied by conceptual density functional theory (CDFT) at the B3LYP/6-311++G(3df,2p) level of theory. In principle, the selectivity is directly related to the mechanisms of sulfur removal. It cannot be precisely elucidated until the mechanisms are totally known. However, current work shows that relationships can be constructed between CDFT and the selectivity. That is, for hydrodesulfurization, good descriptors will be ionization energy, hardness, and bond lengths of SC; for adsorptive desulfurization, the hardness is a good descriptor; for oxidative desulfurization, good descriptors are electron density and Fukui function. And for extractive desulfurization (nonmetal-based ionic liquids), electron affinity and electrophilicity may be good descriptors. In addition, structures and frontier orbitals of various sulfides have also been discussed. It is hoped that these relationships between CDFT and selectivity can give useful information to develop highly efficient sulfur removal methods for specific sulfides, like 4,6-dimethyldibenzothiophene, and 4-methyldibenzothiophene. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2087-2100, 2016 [ABSTRACT FROM AUTHOR]

[Display omitted] • The species which Al atom anchoring on B site of h-BN is more stable. • The Al_edge_B 1 and Al_edge_B 2 species is more stable than other forms for Al-BN-SAAs. • All Al-BN-SAAs have superior ADS performance than pristine h-BN. • The enhanced performance is attributed to the newly formed S Al coordination bond. A concept of single atom adsorbents (SAAs) is proposed to the fields of highly selective adsorption desulfurization from diesel. Here, SAAs with the Al atom anchoring on the surface of hexagonal boron nitride have been systematically explored by density functional theory. Firstly, all the possible doping sites have been considered and their stabilities have been discussed by the doped energy. Additionally, the activity and selectivity for the adsorptive desulfurization of these Al-based SAAs have been predicted. Results show that all the Al-based SAAs can enhance the activity and selectivity of adsorptive desulfurization due to the newly formed S-Al coordination bond. We hope this work can provide a reliable theoretical foundation for the design of SAAs with higher adsorptive activity and superior selectivity. [ABSTRACT FROM AUTHOR]

In this work, interaction nature between a group of aromatic sulfur compounds and [BMIM] + [FeCl 4 ] − have been investigated by density functional theory (DFT). A coordination structure is found to be critical to the mechanism of extractive desulfurization. Interaction energy and extractive selectivity follow the order: thiophene (TH) < dibenzothiophene (DBT) ≈ benzothiophene (BT). Alkylation of TH or BT ( e.g. 3-methylthiophene, and 3-methylbenzothiophene) leads to a stronger interaction with ionic liquid, but steric hindrance effects of some alkylic derivatives ( e.g. 2,7-dimethylbenzothiophene) lead to a weaker interaction with ionic liquid. The mechanism of extractive desulfurization is attributed to the charge transfer effect. During extractive desulfurization, electrons on aromatic sulfur compounds transfer into the Lewis part of ionic liquid, namely, [FeCl 4 ] − . Furthermore, it is better to consider the Lewis acidity of Fe-containing ionic liquid by the whole unit (such as [FeCl 4 ] − and aromatic sulfur compounds (X)) rather than only Fe or S atom. [ABSTRACT FROM AUTHOR]

Five low-cost deep eutectic solvents (DESs) were synthesized based on choline chloride (ChCl) and a series of straight-chain monobasic acids. Under UV light irradiation, one-pot extraction combined with the metal-free photochemical aerobic oxidative deep desulfurization of fuels in deep eutectic solvents was successfully achieved. This liquid-liquid extraction and photochemical oxidative desulfurization system (EPODS) comprised of air, isobutylaldehyde (IBA), DESs and model oil. The factors influencing sulfur removal were systematically investigated, including the amount of DES, volume ratio of model oil and IBA, different sulfur concentrations, different substrates and fuel composition. The sulfur removal of dibenzothiphene (DBT) could reach 98.6% with air as oxidizing agent under UV light irradiation. Sulfur removal by different sulfur compounds decreased as BT ＞ DBT ＞ 4,6-DMDBT. The possible photochemical oxidative desulfurization mechanism was researched by gas chromatograph-mass spectrometer (GC-MS), electron spin-resonance (ESR) spectroscopy and density functional theory (DFT). [ABSTRACT FROM AUTHOR]

Adsorptive desulfurization (ADS) by hexagonal boron nitride (h-BN) is a promising technology to remove the sulfur compounds from fuels. In the present work, the dibenzothiopehene (DBT) adsorption strength on the pristine and O-doped h-BN monolayer has been investigated by density functional theory (DFT) calculations. A series of monoatomic and diatomic doping forms at different positions and contents have been constructed. According to the calculational results, all the O-doping forms can enhance the ADS performance. Among them, it is found that O-bri-B-N and OH-top-B doping models mainly contribute to the enhancement of the ADS performance. Additionally, as the doping content increases, the ADS performance can also be enhanced. By employing quantum chemical analysis, the enhancement mechanism is ascribed to the newly formed O···H–C hydrogen bond, while the π–π interaction is still maintained. Therefore, we proposed that the O-doped boron nitride material can be applied to diesel adsorptive desulfurization. [Display omitted] • O-doped hexagonal boron nitride adsorbents were studied by DFT. • All the O-doping forms can enhance the ADS performance. • O-bri-B-N and OH-top-B doping models contribute mainly to the ADS performance. • Mechanism is ascribed to the newly formed O···H–C hydrogen bond and π–π interaction. [ABSTRACT FROM AUTHOR]

With the rapid growth in fuel demand, deep desulfurization of fuel oil is vitally necessary for the sake of health and environmental protection. In this work, a kind of magnetic ionic liquid supported silica is prepared by a facile ball milling method, and applied in the aerobic oxidative desulfurization of organosulfurs in fuel. The experimental results indicated that ball milling procedure can increase the specific surface area of samples, which is beneficial to oxidative desulfurization process. Under the optimal reaction conditions, the prepared materials can have an entire removal of aromatic sulfur compounds as well as a good recycling ability. Moreover, the introduction of Fe3O4 did not decline the desulfurization performance, but help the catalyst to be easily separated after reaction. [ABSTRACT FROM AUTHOR]

Heteroatom doping is an effective strategy to improve the performance of adsorbents. Here, a comparative study of halogen-doped (X=⎔Cl, Br, I) hexagonal boron nitride (h-BN) materials has been systematically performed by density functional theory (DFT) and quantum analytic methods. There are four possible doped sites for h-BN, such as edge_B, edge_N, B vacancy (B v) and N vacancy (N v). DFT results show that the doping stability for these sites are as follows: edge_B > edge_N > N v > B v. Moreover, higher content of halogen-doped h-BN have also been considered. For the adsorptive desulfurization performance, the adsorption strength of dibenzothiophene (DBT) is estimated on all halogen-doped h-BN materials. Results show that all of the halogen-doped h-BN materials possess higher adsorptive desulfurization performance. Quantum analytic methods prove that the higher adsorptive desulfurization performance originates from the additional X···H-C hydrogen bonding interaction while the π-π interaction is maintained. [Display omitted] • X-doped (X=Cl, Br, I) hexagonal boron nitride adsorbents were studied by DFT. • There are four possible doping sites where the form of X_edge_B is most stable. • The adsorptive energies of DBT for these X-doped h-BN materials are all enhanced. • The enhanced mechanism between DBT and X-doped h-BN has been investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] High entropy oxides are promising catalysts for numerous catalytic oxidation processes with oxygen as the oxidant. However, most of them often show bulk morphologies, which hinders the full exposure of active sites. In this work, a unique 26-faceted polyhedral high entropy oxide MnNiCuZnCoO x -1000 (P-HEO) with highly active site exposure is fabricated via a mechanochemistry-assisted strategy. By employing such a strategy, the supersaturation of P-HEO during the crystal growth process is effectively reduced to form high-index facets, which is proved to be beneficial to the formation of high-index facets. Characterization results indicate that more oxygen vacancies are generated in P-HEO compared with the bulk counterparts. Density functional theory calculations reveal that the high-index facets { −2 1 1} can facilitate adsorption and activation of O 2 because of the higher adsorption energy −2.23 eV compared with that of (1 1 1) surfaces (-1.79 eV), which induces significantly enhanced activity for organic sulfides oxidation. Interestingly, the synthesized P-HEO with high-index facets shows a 98.4% removal rate of dibenzothiophene from model oil within 8 h at 120 °C, which is much higher than that of the bulk counterparts (33.5%). [ABSTRACT FROM AUTHOR]

[Display omitted] • An OCNR method has been first proposed for the controllable synthesis of functionalized PPILs. • The protic ion pairs play a crucial role in the formation of PPILs with low viscosity. • The PPILs possess excellent extractive capacity due to the rapid mass transfer offering enough electrons for DBT. • The primary driving forces for the extraction of DBT are the interactions of C H·π in protic ion pairs sites and C H···O in HS sites. Porous ionic liquids (PILs) offer a distinctive combination of liquid-like fluidity and solid porosity, making them well-suited for various applications including separation, catalysis, and energy storage. Nevertheless, the design limitations and complex synthesis processes have hindered the development of PILs. Here, the one-step coupling neutralization reaction (OCNR) method has been first proposed for the controllable synthesis of functionalized protic porous ionic liquids (PPILs). Specifically, three types of PPILs have been synthesized based on tuning the position of the corona amino functional groups. The results indicate the crucial role of protic ion pairs in the formation of pure liquid PPILs with low viscosity. The extraction efficiency has obviously increased after introducing the porous materials from 38.5% to 51.9%. The results showed PPILs play good extraction-adsorption coupled desulfurization (EADS) performance. The density functional theory (DFT) results show that both the protic ion pairs and the porous structure have significant roles in EADS, with the former offering C H···π interactions, while the latter provides hydrogen bonding (C H···O) interactions. Ultimately, the strategy simplifies the synthesis process, providing a new idea for the directional design of low-viscosity PILs with specific functions. [ABSTRACT FROM AUTHOR]

Herein, functional molybdenum-containing ordered mesoporous silica (Mo-OMS) were successfully fabricated from imidazole and polyoxometalate-based ionic liquids, and employed for the removal of organosulfur compounds. The composition and structure of as-prepared materials were characterized in detail by FT-IR, Raman, DRS, low and wide-angle XRD, nitrogen adsorption–desorption and TEM. The hybrid materials exhibited a high dispersion of molybdenum species and good activity on removing organosulfur compounds without any organic solvents as extractants. Various effects such as the amount of samples, O/S molar ratio, temperature, types of sulfur-containing substrate on the sulfur removal were also investigated. Under optimal conditions, dibenzothiophene (DBT) could be completely removed in 50 min. Moreover, the sulfur removal of reaction system could still reach 91% after recycling for nine times. [ABSTRACT FROM AUTHOR]

Construction of photocatalyst that combines excellent electron transfer and photoresponse capabilities to enhance photocatalytic performance remains a challenging task. In this work, interfacial Mo-N bonds and vacancy engineering collaborative modified MoO 3-x @polypyrrole (MP) S-scheme heterojunction is rational designed for efficient photocatalytic oxidative desulfurization. The addition of polypyrrole introduces rich defects which inducing the localized surface plasmon resonance (LSPR) effect and enhancing light absorption. Furthermore, the combination facilitates the formation of Mo-N bonds. The modifications amplify the built-in electric field and conduct the efficacious separation of photogenerated carriers. With the synergism of LSPR effect and interfacial chemical Mo-N bonds, the optimal MP photocatalyst displays attractive desulfurization rate of 100% for dibenzothiophene (DBT) in 60 min under illumination, touching the objective of ultra-deep desulfurization. The study extends a novel understanding of the impact of LSPR effect and heterojunction interface charge transfer on the photocatalytic desulfurization ability. [Display omitted] • S-scheme heterojunction MP with chemical coupling for DBT desulfurization is designed. • The increased OV concentration induces LSPR effect and enhance the light adsorption. • The formation of Mo-N bond enhances interface coupling as electron transfer channel. • e－ of MoO 3-x rapidly combines with h+ of PPy which enhance photocatatlytic ability. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel type of ionanofluids were successfully constructed for ECODS. • Ionanofluids displays high selectivity and recyclability for desulfurization. • The synergistic effect between Mo-MOF and ionic liquids was verified. Ionanofluids as newly introduced types of nanofluids with promising potential for diverse applications are created through dispersing nanoparticles into ionic liquids. Ionanofluids capitalize on both the catalytic ability of nanoparticles and the rapid mass transfer along with the extraction performance of ionic liquids. Herein, a novel kind of ionanofluids (denoted Mo-INFs) was constructed by employing a Mo-MOF as the nanoparticle and an imidazole-based ionic liquid ([BDIM][NTF 2 ]) as the base fluid. As the efficiency of Mo-INFs (97.9 %) surpassed the summarized efficiency of Mo-MOF and [BDIM][NTF 2 ], a synergistic effect between the Mo-MOF moiety and the [BDIM][NTF 2 ] moiety in Mo-INFs did exist. Under optimum reaction conditions, the Mo-INFs exhibited remarkable selectivity and recyclability in desulfurization. A possible desulfurization mechanism was proposed that aromatic sulfur compounds in the model oil phase were initially extracted into ionanofluids phase via C-H···π and π···π interactions and subsequently oxidized by peroxo species that formed in the presence of H 2 O 2 and Mo-MOF. [ABSTRACT FROM AUTHOR]

[Display omitted] • UiO-66-BAPILs were designed and fabricated for oxidative desulfurization. • The permanent cavity in UiO-66-BAPILs was validated by gas uptake experiments and molecular size simulations. • UiO-66-BAPILs exhibited higher catalytic activity than the two components. • The mechanism was in detail studied by experiments and theoretical calculations. Porous ionic liquids have been highlighted with special interest for their desirable catalytic activity and extraction properties. Herein, bifunctional porous ionic liquids (denoted UiO-66-BAPILs) were synthesized by dispersing UiO-66 into a pyridinium-based Brønsted acidic ionic liquid ([BSPy][CF 3 SO 3 ]) for oxidative desulfurization. The permanent cavity of UiO-66 moiety in UiO-66-BAPILs was validated as well-preserved by the SO 2 uptake experiments and molecular size simulations. Under the optimum reaction conditions, the sulfur removal could reach up to 99.5% with hydrogen peroxide as the oxidant. Additionally, bifunctional UiO-66-BAPILs were deemed as both extractants and catalysts during the reaction. A possible mechanism has been proposed that UiO-66-BAPILs extract the aromatic sulfur compounds via π···π interactions and C-H···π interactions and meanwhile oxidize them with peroxysulfonic acids and •OH radicals. These findings will open up new avenues to facilitate the catalytic oxidation performance by constructing bifunctional Brønsted acidic porous ionic liquids. [ABSTRACT FROM AUTHOR]

• A novel electronic modulation strategy on metal-free catalyst via organic modification was proposed. • The electron transfer effect was well proved and the electron transfer direction was clarified. • A deep oxidative desulfurization can be achieved with the residual sulfur content less than 10 ppm. • The mechanism of the improved catalytic activity was illustrated clearly. Tuning electronic structure of metal catalysts by organic modification is an efficient strategy for domination of their catalytic performances. However, the electronic structure tuning over metal-free catalysts remains to be a challenge. In this work, an organic modification strategy with deep eutectic solvents (DES) as organic modifier over metal-free catalysts was proposed to tune the electronic structure of hexagonal boron nitride (h-BN). Detailed experiments showed that the electronic properties of h-BN was rationally tuned by the introduced DES, in which the B atoms in h-BN were positively charged. Meanwhile, the modulated electronic properties can lower the activation energy for the generation of hydroxyl radicals (•OH) from hydrogen peroxide (H 2 O 2), thus leading to a promoted catalytic performance in oxidative desulfurization. This finding may pave a new strategy for tuning metal-free catalysts with highly-active catalytic performance. An organic ligand modification strategy over metal-free boron nitride catalyst. [Display omitted] [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]

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]

• Dual Brønsted DESs were designed as extractants and catalysts for oxidative desulfurization. • The reaction mechanism was studied in depth through experimental and theoretical method. • Synergistic effect made the DES showed higher catalytic activity than other DESs. • Decreasing viscosity of DES was verified as effective strategy to improve reaction rate. Deep eutectic solvents (DESs) are generally used as attractive solvents or extractants rather than catalysts in the field of synthesis and separation. Herein, dual Brønsted acidic DESs were prepared by mixing sulfonated quaternary ammonium and oxalic acid as extractants and catalysts for deep oxidative desulfurization. Compared to the DESs with single acidic group, the dual acidic DESs exhibited much higher catalytic activity likely due to the synergistic effect. The 1H NMR study indicated that the weak interaction between DES and sulfur compounds led to a low extraction capacity. However, the sulfur removal could reach 97.7% under optimized reaction conditions. Density functional theory (DFT) calculations demonstrated that sulfonic group and carboxylic group are of equal importance to desulfurization performance. Further, the desulfurization efficiency was also strongly affected by the viscosity of DESs. Here, we put forward a new strategy that the reaction time could be sharply shortened to 40 min and 100 min by adding low viscous acetonitrile and polyethylene glycol into DES to form mixing reaction system, respectively. [ABSTRACT FROM AUTHOR]

Sulfur compounds in oil phase were captured into the catalyst phase, then oxidized to their corresponding sulfones in the presence of molecular oxygen. • A series of electrophilicity-tunable ionic liquids were successfully synthesized via a facile ion exchange method. • Both cation and anion parts in ionic liquid played an important role in ODS process. • The prepared ionic liquid [C 4 VIM]PMoV 2 exhibited high efficiency in aerobic ODS process under mild conditions. • The structure-function relationship was investigated in detail from various methods. With increasing stringent standard of sulfur content in fuels, deep desulfurization with high-efficiency is necessary for ecological and environmental demands. Herein, vanadium-substituted polyoxometalate-based ionic liquids with tunable electrophilicity were facilely synthesized through ion exchange method, and applied in the aerobic oxidative desulfurization. The experimental results indicated that both imidazole cation and polyoxometalate anion played a vital role in the desulfurization process. The prepared materials have a good performance on the degradation of aromatic sulfur compounds, which can reach up to 98.9 % under optimal conditions. Moreover, the structure-function relationship was also investigated in detail, as well as the proposed mechanism. [ABSTRACT FROM AUTHOR]

The defective MoO 3 derived from Mo-based MOF was highly dispersed on nitrogen-doped porous carbon (V O -MoO 3 @NPC) by a single-step carbonization treatment. Notably, V O -MoO 3 @NPC realizes an extraordinary desulfurization efficiency of 99.1% within 20 min coupled with an exceedingly remarkable TOF of 96.2 h−1 owing to plentiful oxygen vacancies and effective electron transfer. [Display omitted] • V O -MoO 3 @NPC derived from Mo-MOF was prepared via an in situ annealing strategy. • Richer oxygen vacancies are formed due to the stronger metal-support interaction. • Incorporating nitrogen facilitates the electron transfer by shrinking the band gap. • V O -MoO 3 @NPC realizes an outstanding catalytic ODS activity of 99.1% within 20 min. • TOF can reach 96.2 h−1 by V O -MoO 3 @NPC but only 50.2 h−1 by V O -MoO 3 @PC. Electron transfer between supports and metal oxides is of great significance in optimizing the catalytic activity, while this is still an open issue for understanding its real role in the oxidative desulfurization (ODS) process. Herein, the defective molybdenum trioxide derived from molybdenum-based metal–organic frameworks was highly dispersed on nitrogen-doped porous carbon (V O -MoO 3 @NPC) by a single-step carbonization treatment. The uniform integration of organic moieties and the unique porous structure of carbonaceous materials are conductive to the active site exposure and mass transfer process during the ODS reaction. Meanwhile, richer oxygen vacancies are generated due to the weakened Mo-O bonds, which is pertinent to the promoted electron transfer between nitrogen-doped porous carbon and molybdenum trioxide by shrinking the band gap. The results manifest that the obtained V O -MoO 3 @NPC realizes an extraordinary desulfurization efficiency of 99.1% within 20 min, as well as a stable recyclability of up to 9 times. Furthermore, the catalyst delivers an extremely remarkable turnover frequency of 96.2 h−1, which is far superior to that of previously reported molybdenum-based catalysts. This manuscript provides new inspiration for designing excellent ODS catalysts by introducing electron-rich nitrogen to construct strong metal-support interactions. [ABSTRACT FROM AUTHOR]

A stronger Lewis acid-base interaction is constructed between B-C 3 N 4 and aromatic sulfides, which makes the active sites more accessible. [Display omitted] • Lewis acidity is enhanced by tuning the electronic structure of g-C 3 N 4 (B-C 3 N 4). • Enhanced Lewis acidity induces stronger interaction between catalysts and sulfides. • B-C 3 N 4 were applied in oxidative desulfurization as metal-free catalysts. • B-C 3 N 4 shows 100% of removal to 4,6-DMDBT with oxygen molecules as the oxidant. Regulation of electronic properties has been found to be an effective strategy to boost catalytic performance. In this paper, boron doped graphene-analogous carbon nitride (B-C 3 N 4) was prepared and applied in aerobic oxidative desulfurization (ODS) as a metal-free catalyst. Detailed characterizations showed that B atoms have been doped into the framework of carbon nitride, which redistributes the electron structures and appears a stronger Lewis acidity. The B-C 3 N 4 exhibited an impressive sulfur removal to aromatic sulfides, especially to 4,6-dimethyldibenzothiophaene, and the catalytic ability of different sulfides was 4,6-dimethyldibenzothiophene > 4-methyldibenzothiophene > dibenzothiophene. A stronger adsorption progress was constructed between Lewis acid B-C 3 N 4 and Lewis basic aromatic sulfides by the Lewis acid-base interaction, which benefits the next oxidation reaction during the ODS process. After recycling 5 times, the sulfur removal of B-C 3 N 4 could still remain higher than 90%. The current method provides a potential application of B-C 3 N 4 for the removal of 4,6-dimethyldibenzothiophene. [ABSTRACT FROM AUTHOR]

[Display omitted] • BN-UM6:4 exhibits an excellent ADS capacity of 47.2 mg S/g adsorbent. • The porosity was finer adjusted by modifying the composition of N precursor. • Compared to solvent-based method, solvent-free method achieves higher micropore ratio. • Abundant micropores effectively enhance ADS performance (R2 > 0.8). • S-N covalent bonds and C-H···N hydrogen bonds are the main driving. Construction of structurally stable and highly porous materials, like hexagonal boron nitride (h-BN), is a prerequisite for achieving efficient adsorptive desulfurization (ADS). Nevertheless, the present constraints in precisely adjusting the pore structure parameters of BN impede its further utilization in the field of adsorption. In this study, highly porous boron carbon oxynitride (BCNO) adsorbents were synthesized via a straightforward, one-step solvent-free reaction. By modifying the composition of nitrogen (N) precursors, it was possible to finer tuning the micropore ratio thereby leading to a substantial increase in micropore surface area. Moreover, the fitting coefficients (R2) between S micropore , V micropore , and adsorption capacity are 0.81959 and 0.80547, indicating a strong correlation between the microporous structure and the ADS performance. The prepared BCNO-UM6:4 adsorbent showed excellent adsorption performance with a capacity of 47.2 mg S/g adsorbent, surpassing the adsorbents synthesized using solvent-based methods (39.4 mg S/g adsorbent) and single-source N synthesis (BCNO-U18 32.1 mg S/g adsorbent, BCNO-M6 12.1 mg S/g adsorbent). Experimental results revealed that the main adsorption mechanism is multi-layer adsorption by the micropore filling. Density functional theory (DFT) revealed that the newly formed S-N covalent bonds and C-H···N hydrogen bonds are the main driving forces. In summary, this synthetic method expands the production pathway of porous BCNO and has potential application in various research fields. [ABSTRACT FROM AUTHOR]

Mo-based MOFs with various organic linkers showed fast desulfurization performance and high stability. [Mo(O 2)] was deduced as the main active oxygen species for the conversion of DBT to DBTO 2. The sulfur removal could reach 99.4% within 12 min over the obtained Mo-MOF-PI due to the high dispersion of Mo atoms. [Display omitted] • Mo-MOFs were constructed through assembling various organic linkers and MoO 3. • Mo-MOF-PI could achieve 99.4% sulfur removal with only 12 min. • ODS can be enhanced by the stronger interaction caused by the longer carbon chain. • Mo-MOF-PI showed high TOF value (19.2 h−1) and reused at least 20 times. • [Mo(O 2)] was deduced as the main active oxygen species for conversion DBT to DBTO 2. Heterogeneous catalysts are usually constructed by immobilizing active species on appropriate supports. However, the dispersibility is difficult to precisely control. In this work, three representative Mo-based MOFs (Mo-MOFs) were constructed by assembling various organic linkers and MoO 3 , where the Mo atoms are homogeneously dispersed due to the coordination. The results illustrated that the obtained Mo-MOF-PI synthesized with 2-propyl imidazole as the ligands exhibited an extremely fast reaction rate, achieving 99.4% sulfur removal of DBT within only 12 min. Compared to other similar catalysts, Mo-MOF-PI showed much higher catalytic activity with a turnover frequency value of 19.2 h−1. Moreover, it can be reused at least 20 times without a dramatic reduction in catalytic performance. Thus, the as-prepared Mo-MOF catalysts show great potential in large-scale industrial applications. [ABSTRACT FROM AUTHOR]

Modeling the structure-activity relationships (SARs) of deep eutectic solvents (DESs) is crucial for upgrading their catalytic performance in targeted reactions. Herein, a series of Brønsted acidic DESs are developed for the SARs research at molecular and atomic levels. Experimental and theoretical results suggest that the catalytic activity increases with the decreasing distances between O atom of active sites in DESs and S atom in sulfur compounds, and the R2 between EODS efficiency and the valid distances of O···S is above 0.9. Such geometric configuration can be optimized by altering the composition of DESs, which in turn substantially triggers the reaction acceleration between active intermediates and substrates. The resulting DES (TEAC/2BSA) achieved deep desulfurization for various sulfur compounds based on the optimal valid distances of O···S. This work contributes to a deep understanding of the reaction mechanism and enables the effective screening of task-specific DESs. [Display omitted] ● Structure-activity relationships in EODS reaction over Brønsted acidic DES were revealed. ● Valid interatomic distance of O···S of DES and DBT is critical for the desulfurization performance. ● Structural properties and reaction environment were optimized by altering the components in DESs. ● TEAC/2BSA achieve superior sulfur removal compared to published sulfonic acid-based DESs. [ABSTRACT FROM AUTHOR]

Magnetic core-shell structured materials as carriers have received extensive attention in heterogeneous catalysis due to their unique magnetic responsively properties. Herein, we report a synthetic route to obtain magnetic core-shell microspheres by a sol–gel approach. The Fe 3 O 4 (ca. 8 nm) is completely coated with SiO 2 (ca. 15 nm) to prevent Fe 3 O 4 from being oxidized in the reaction and the microspheres also show superparamagnetism, which allows the catalyst easy to separate. To explore their application, Mo-containing compound is loaded to their surface by impregnating and then calcined at different temperatures (100–800 °C). The obtained catalysts are used in oxidative desulfurization (ODS). The removal of DBT from model oil can reach 100% with calcination temperature at 400 °C and be recycled for at least five times without obvious decrease. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of novel and stable PILs were constructed for ECODS. • The permanent porosity of PILs was confirmed by gas uptake and molecular simulation. • PILs exhibited high catalytic activity for oxidative desulfurization. • The synergistic effect between UiO-66 moiety and IL moiety was verified. • The mechanism of ECODS systems was systematically studied and proposed. Porous ionic liquids are a novel category media that possesses the catalytic activity of porous solids and the extraction property of ionic liquids. Herein, a new type of porous ionic liquids (denoted as UiO-66-T3PILs) was fabricated by employing UiO-66(Zr) as the pore generator and the ionic liquid ([P 6,6,6,14 ][NTF 2 ]) as the size-excluded solvent for extraction coupled catalytic oxidative desulfurization (ECODS) using hydrogen peroxide (H 2 O 2 , 30 wt%) as an oxidant. Furthermore, several significant reaction parameters such as UiO-66 loading in porous ionic liquids, reaction temperatures, molar ratio of H 2 O 2 /DBT and sulfide species as well as recyclability were investigated in detail. As UiO-66-T3PILs exhibited higher efficiency (95.3%) than the summarized efficiency of UiO-66 and [P 6,6,6,14 ][NTF 2 ], there did exist a synergistic effect between the UiO-66(Zr) moiety and the ionic liquid moiety in UiO-66-T3PILs. With the assistance of density functional theory calculations, a possible mechanism was proposed that aromatic sulfur compounds in the oil phase were first extracted into ionic liquids moiety phase via C-H···π interactions and then rapidly oxidized by OH radicals in the presence of the UiO-66 moiety. This work will pave the way for the rational design of novel porous ionic liquids towards catalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • BCN doped with Cu(I) adsorption sites have been successfully prepared. • BCN-Cu-0.04 shows remarkably enhanced ADS performance. • BCN-Cu-0.04 displays high adsorption selectivity for 4,6-DMDBT. • The main force is S-Cu coordination and π-π interaction. Boron carbon nitride (BCN) has emerged as an effective material owing to its high specific surface area, porous structure, and excellent chemical inertness. However, the existing BCN adsorbents for adsorption desulfurization (ADS) exhibit inferior adsorption capacity and selectivity. Herein, a series of novel BCN nanofibers doped with Cu(I) adsorption sites (BCN-Cu-X, X = 0.02, 0.04, 0.06, 0.08 mmol) were fabricated via a simple one-pot pyrolysis method derived from a carboxylic acid copper coordination compound. The results demonstrated that BCN-Cu-0.04 shows a remarkably increased adsorption capacity for dibenzothiophene (DBT) about 33% higher than BCN under the same conditions. It is also noteworthy to mention that BCN-Cu-0.04 presents high ADS performance even for the refractory sulfur compound 4,6-Dimethyldibenzothiophene (4,6-DMDBT, 42.2 mg S/g adsorbent). Furthermore, density functional theory (DFT) calculations proved that the enhanced performance of BCN-Cu-X in ADS is attributed to the π-π interaction and newly formed sulfur-copper (S-Cu) coordination bond, which is different from other Cu-based adsorbents. This study may inspire the development of new synthetic routes which are possible to realize high-efficiency and high-selectivity ADS. [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]

• POM-based PILs with high specific surface area were successfully prepared with template-free strategy. • Deep oxidative desulfurization and recycling ability can be achieved without any extractant. • The structure–activity relationship was investigated through various technologies. • DFT calculations were employed to investigate the interaction nature between catalysts and sulfides. Interfacial properties of catalysts and distribution of active sites affect the catalytic oxidative desulfurization activity, which has become the research focus in recent years. Towards desulfurization in fuel, a kind of amphiphilic and polyoxometalate poly(ionic liquids) was prepared by the cross-linking copolymerization and ion exchange reaction. The resulting samples characterized in detail were employed in the oxidation of refractory aromatic sulfur-containing compounds. With H 2 O 2 as the oxidant, the sample p-C 2 VIM-DVB-2-PMo exhibited enhanced desulfurization performance and good thermal stability, meeting the demand of deep desulfurization. Besides, no significant decrease on sulfur removal was observed after recycling for 8 times. Moreover, density functional theory calculations were employed to investigate the adsorption strength and interaction nature between the cation and typical sulfide. [ABSTRACT FROM AUTHOR]

Porous ionic liquids (PILs) are an emerging class of materials that possess the porosity of solids and the fluidity of liquids, which have shown great potential in separation. Herein, a novel kind of silica-based porous ionic liquids (OS-PIL) functionalized with quaternary ammonium salt was successfully synthesized to remove the dibenzothiophene (DBT) in the model fuel. The OS-PIL exhibit high extraction activity and its Nernst partition coefficient could reach up to 4.22. The experimental results indicated that a synergistic effect between porous materials and ionic liquids as well as the multiple sites in quaternary ammonium salt greatly contributed to the high extractive desulfurization efficiency. Moreover, density functional theory (DFT) calculations and spectroscopic investigations were employed to gain in-depth insights into the extraction mechanism. The results demonstrated that the porous structure and ion pair of OS-PIL exhibit stronger interaction for DBT, in which the C-H···π is dominant. These kinds of PILs with highly specific surface areas and multiple active sites will have good application prospects in the field of extractive desulfurization. [Display omitted] • OS-PIL was designed as an extractant for desulfurization. • The synergistic effect resulted in the OS-PIL showing high extraction activity. • The extractive mechanism has been thoroughly investigated by experimental and theoretical methods. • C-H···π is the major weak interaction between OS-PIL and DBT. [ABSTRACT FROM AUTHOR]

The combination of distinctive properties of carbon nanotubes and metal oxides is expected to exploit novel catalysts offering high catalytic ability. Herein, a nano-sized MoO 2 derived from molybdenum-based metal-organic framework was anchored on the surface of carbon nanotubes (CNT) with urea as a regulator. Powder X-ray diffraction analysis suggested that the nitrogen content and the MoO 2 particle size of the as-prepared catalyst could be tuned by changing the urea dosage and the calcination temperature. Elemental mapping indicated the homogeneous dispersion of the nano-sized MoO 2 on the surface of CNT for MoO 2 @CNT-U 7.5 (U 7.5 represents mass ratio of urea to CNT). Compared with MoO 2 @CNT treated in absence of urea, MoO 2 @CNT-U 7.5 showed extremely higher catalytic performance in oxidative desulfurization of fuel. With H 2 O 2 as an oxidant, the removal of refractory sulfur compounds including dibenzothiophene, 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene can reach >99% within 40 min at the reaction temperature of 50 °C. In addition, the catalyst exhibited superior cycling stability and could be recycled for eight times with little loss of sulfur removal. The reaction mechanism was eventually proposed with the assistance of GC–MS and ESR analysis. Sulfur compounds in fuel burnt to produce sulfur oxides will do harm to the environment. This work can not only remove the sulfides in the fuel oil to protect the environment through the method of adsorption-oxidative desulfurization, but also can recycle the oxidation products as a valuable resource. [Display omitted] • Carbon nanotubes supported MoO 2 catalysts with tunable nitrogen content and particle size were fabricated. • Urea played an important role on adjusting nitrogen content and particle size. • Removals of refractory sulfur compounds including DBT, 4-MDBT and 4,6-DMDBT can reach >99% within 40 min • The catalyst exhibited superior cycling stability and the oxidative product could be recycled as valuable resources. [ABSTRACT FROM AUTHOR]

In this study, a new type of “green solvents” named deep eutectic solvents (DESs) has been synthesized by combining hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). Choline chloride (ChCl) was chosen as typical HBA, and polyethylene glycol (PEG), 1,3-butyleneglycol (BG), ethylene glycol (EG), glycerol (Gl), propionate (Pr), malonic acid (MA) and urea (U) were chosen as HBDs. The extraction and catalytic oxidative desulfurization (ECODS) system was evaluated with phosphotungstic acid (HPW) as catalyst and 30 wt% H 2 O 2 as oxidant. Among all the neutral, acid and basic DESs, choline chloride/2polyethylene glycol (ChCl/2PEG) showed the best performance and 99.1% of dibenzothiophene (DBT) could be eliminated from model oil at 50 °C within 3 h. Interestingly, the volume ratio of DES to model oil was just 1:10, which was much less than the amount of extractant in the literature. The gas chromatography–mass spectrometer (GC–MS) analysis demonstrated that DBT sulfoxide (DBTO) and sulfone (DBTO 2 ) were the products of oxidation of DBT. The desulfurization efficiency of the five sulfides in ECODS system occured in the following order: DBT > 4-MDBT > 4,6-DMDBT > 3-MBT >BT. [ABSTRACT FROM AUTHOR]

Recently, graphene-like boron nitride (g-BN), has been developed a new application, as a catalyst for aerobic catalysis, which gives it a passport to catalytic field. However, its way to be a high-active one is blocked by its insulation property. In this work, copper nanoparticles (Cu NPs) with nano-size and low resistivity, are confined through g-BN (Cu NPs/g-BN) to boost electron mobility by a simple one-pot pathway. Experiments show that Cu NPs/g-BN hosts a better performance in aerobic oxidation of aromatic sulfur compounds with a catalytic activity of >97%. Cyclic voltammetry (CV) curves give a testimony that the presence of Cu NPs for raised electron mobility is a key element to the high catalytic activity. Besides, the catalyst can be recycled for 10 times without significant decrease in aerobic catalytic activity, which is found to be related with the idiosyncratic oxidation-resisting property of Cu NPs. Experiments find that the extraordinary oxidation-resisting property of Cu NPs mainly relates to the existence of g-BN, which can keep Cu NPs away from being oxidized. This work provides another sight for enlargement of application of g-BN for aerobic catalysis and a new strategy for preservation of NPs. [ABSTRACT FROM AUTHOR]

A supported SiW 12 O 40 -based ionic liquid (SiW-IL) catalyst with high catalytic activity is designed and synthesized by sol–gel method. The supported catalyst had amphiphilic property, making it exhibit good catalytic performance in solvent-free oxidative desulfurization system. The removal of dibenzothiophene (DBT) with the supported catalyst reached 99.9%, while the sulfur removal is only 6.3% with SiW-IL. The characterizations show that SiW-IL is supported on the carrier successfully and the supported catalyst had a sheet-shaped morphology. Then, various of experimental conditions were taken into consideration to investigate the influences of the desulfurization efficiency and the optimal conditions were obtained. Additionally, sulfur removal of different substrates decreased in the following orders: DBT > 4-MDBT > 4,6-DMDBT > BT under the same conditions. GC–MS analysis was employed to study the mechanism of the desulfurization, DBT sulfone was proved to be the oxidizing product of DBT. Moreover, the supported catalyst had a good thermal and chemical stability, and sulfur removal of DBT still remained 96.2% after recycling 7 times. [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]

The rational design of the single transition metal atoms (Cu and Ni) anchoring on the boron nitride (TM-BN) pristine and defective monolayer has been investigated by means of density functional theory. Our calculations revealed that both B-vacancy (V B) and N-vacancy (V N) on BN monolayer are good sites for trapping Cu and Ni atoms. TM/V N and TM/h-BN systems exhibit high catalytic activity toward O 2 activation and subsequent oxidative desulfurization (ODS) reactions. Considering the stability, the TM/V N is expected to be a good catalyst for ODS process. DFT calculations reveal the single metal atom (Cu and Ni) trapped on the V N of h-BN plays a key role for the O 2 activation, and the subsequent oxidation of DBT into DBTOO. [Display omitted] • Ni and Cu single metal atom anchored on the monovacancy B or N site of h-BN are energetically stable. • O 2 readily adsorbs on TM/V N surface and be activated to O 2 − species. • Cu/V N and Ni/V N systems are expected to the good catalysts with high activity toward ODS process. [ABSTRACT FROM AUTHOR]