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The transport and dispersion (T&D) of catalyst particles seeded by weather modification aircraft is crucial for assessing their weather modification effects. This study investigates the capabilities of the Chinese geostationary weather satellite FY-4A for identifying the physical response of cloud seeding with AgI-based catalysts and continuously monitoring its evolution for a weather event that occurred on 15 December 2019 in Henan Province, China. Satellite measurements are also used to verify an operational catalyst T&D algorithm. The results show that FY-4A exhibits a remarkable capability of identifying the cloud-seeding tracks and continuously tracing their evolution for a period of over 3 h. About 60 min after the cloud seeding, the cloud crystallization track became clear in the FY-4A tri-channel composite cloud image and lasted for about 218 min. During this time period, the cloud track moved with the cloud system about 153 km downstream (northeast of the operation area). An operational catalyst T&D model was run to simulate the cloud track, and the outputs were extensively compared with the satellite observations. It was found that the forecast cloud track closely agreed with the satellite observations in terms of the track widths, morphology, and movement. Finally, the FY-4A measurements show that there were significant differences in the microphysical properties across the cloud track. The effective cloud radius inside the cloud track was up to 15 μm larger than that of the surrounding clouds; the cloud optical thickness was about 30 μm smaller; and the cloud-top heights inside the cloud track were up to 1 km lower. These features indicate that the cloud-seeding catalysts led to the development of ice-phase processes within the supercooled cloud, with the formation of large ice particles and some precipitation sedimentation. [ABSTRACT FROM AUTHOR]

Herein, we explore how OH groups on Pt/γ‐AlOOH and Pt/γ‐Al2O3 catalysts affect CO2 hydrogenation with H2 at temperatures from 250°C to 400°C. OH groups are abundant on γ‐AlOOH, but rare at Pt‐(γ‐AlOOH) interface which is the most favorable site for CO2 conversion on Pt/γ‐AlOOH. This makes CO2 hydrogenation on Pt/γ‐AlOOH form CO weakly bonding to γ‐AlOOH, which prefers to desorption from Pt/γ‐AlOOH rather than further conversion, thus enhancing CO production on Pt/γ‐AlOOH. Different from Pt/γ‐AlOOH, OH groups are abundant at Pt‐(γ‐Al2O3) interface which is the most favorable site for CO2 conversion on Pt/γ‐Al2O3. This promotes CO2 hydrogenation on Pt/γ‐Al2O3 to form CO strongly bonding to Pt, which prefers to further hydrogenation to CH4, and thereby increases CH4 selectivity on Pt/γ‐Al2O3. Therefore, the OH groups at metal‐support interface are crucial factor influencing product distribution, and must be considered seriously when fabricating catalysts. [ABSTRACT FROM AUTHOR]

Recent advances in supported nickel catalysts for the water‐gas shift (WGS) reaction are reviewed, focusing on the structure‐mechanism relationships. The WGS reaction can proceed via the redox, carboxyl, and formate pathways over the supported nickel catalysts. However, a discrepancy exists between the mechanism‐level understanding and catalyst design principles in literature. In this review, we summarized the mechanism‐structure relationship of nickel‐based catalysts, emphasizing the effects of the formation of alloy, modification of the support or addition of alkali metal promoters on the CO adsorption and the H2O dissociation in the process of WGS reaction. Future research is suggested to systematically investigate the reaction mechanism & kinetics for different catalyst structures. In addition, the manipulation of strong metal‐support interactions and the development of new types of supports are prospective directions. [ABSTRACT FROM AUTHOR]

In the present work, we demonstrate that the mechanism and kinetics of CO2 activation, as the first step of its hydrogenation, over supported nickel catalysts is particle size sensitive owing to the distinct H2 dissociation ability over nickel particles with various sizes. Large nickel nanoparticles facilitate H2 dissociation, enabling CO2 activation via a kinetically favored redox mechanism compared to small nickel nanoparticles that activate CO2 via the formate mechanism. The elucidation of the dependency of the catalytic reaction pathway on particle size will guide the rational design of supported nickel catalysts for selective CO2 hydrogenation. This work demonstrated in the CO2 hydrogenation reaction, CO2 is activated through different mechanisms due to different H2 dissociation capabilities over supported Ni catalysts with different particle sizes, which provides a convincing experimental explanation for the structural sensitivity of nickel‐based catalysts. [ABSTRACT FROM AUTHOR]

Urea, as a significant molecule in biology, chemistry and agriculture, is extensively present both in industrial production and daily life. However, its excessively releasing into water and soil could bring about a serious threat to the environment and ecology due to the potential eutrophication. Considering the potential hydrogen content in urea, urea-rich wastewater is also regarded as a strategic energy storage resource. Among all technologies, the electrochemical treatment of urea wastewater behaves superior advantages both on environment protection and energy recovery, causing tremendous attention in recent years. Herein, this review summarized electrochemical methods for urea conversions for pollutant control and energy harvesting. As the kernel role in the electrochemical systems, the latest development of advanced electrodes is presented with the basic design principles described. The relationships between the electrocatalysts and their urea oxidation performance have been discussed thoroughly. Additionally, recent advances about novel applications for energy production and resource recovery are also displayed. Finally, the prospects and challenges are still to be addressed, orienting a clear direction for the electrochemical hydrogen harvesting from urea-containing wastewater in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • NiMo/Beta(25) possessed high Brønsted acidity and high MoS 2 dispersion. • NiMo/Beta(25) can convert tetralin to mono-aromatic hydrocarbons (MAHs). • A catalyst grading system composed of NiMo/A 30 Y 50 and NiMo/Beta(25) was developed. • This catalyst grading system can efficiently convert 1-methylnaphthalene to MAHs. • 52.7% and 63.8% MAHs selectivities were separately obtained with and without NH 3. Selective hydrocracking of poly-aromatic hydrocarbons (PAHs) to mono-aromatic hydrocarbons (MAHs) over zeolite-supported non-noble metal catalysts is an effective way to upgrade light cycle oil (LCO). However, it is still a challenge to increase the yield of MAHs. Herein, we report that a catalyst grading system consisting of NiMo/A 30 Y 50 (upper catalyst layer) and NiMo/Beta(25) (lower catalyst layer) can efficiently convert 1-methylnaphthalene (1-MN, representative of PAHs in LCO) into MAHs. Experimental and characterization studies reveal that NiMo/Beta(25) can facilitate the conversion of intermediates of 1-MN hydrocracking (mainly methyl tetralins and indanes) into MAHs, mainly due to its good textural property, high Brønsted acidity and high MoS 2 dispersion. Under the experimental condition of 400 °C, 6 MPa, H 2 /1-MN molar ratio = 6 and weight hourly space velocity of 1-MN (WHSV) = 1 h−1, the NiMo/A 30 Y 50 – NiMo/Beta(25) catalyst grading system can realize 99.9% conversion of 1-MN and 63.8% selectivity of MAHs, which outperforms the performance of most catalysts reported in the literature. Moreover, even if the presence of NH 3 in the reaction system, this catalyst grading system can give rise to 98.3% conversion of 1-MN and 52.7% selectivity of MAHs at 420 °C, 6 MPa, H 2 /1-MN molar ratio = 6 and WHSV = 1 h−1. The findings of this study offer new opportunities for the valorization of LCO. [ABSTRACT FROM AUTHOR]

[Display omitted] • The structure-performance relationship of NiMo/Al 2 O 3 -HY was deeply investigated. • The hydrogenation activity of catalysts relied on the density of MoS 2 active sites. • The yield of mono-aromatics depended largely on the density of Brønsted acid sites. • NiMo/A 30 Y 50 had the best performance in selective hydrocracking of poly-aromatics. Oriented conversion of poly-aromatic hydrocarbons into mono-aromatic hydrocarbons (MAHs) via selective hydrocracking over non-noble metal-based zeolite-binder composite catalysts is an effective way to upgrade light cycle oil, which is a poor blending component in diesel pool. However, the lack of understanding of the key structural factors that influence the performance of composite catalysts has hindered their development. In this study, a series of NiMo/Al 2 O 3 -HY bi-functional catalysts with different Al 2 O 3 contents were prepared, characterized, and evaluated. Tetralin and 1-methylnaphthalene were used as model compounds to study the structure-performance relationship of catalysts. It was demonstrated that the hydrogenation activity and MAHs yield of catalysts depended strongly and positively on the density of MoS 2 active sites (C M o S 2 , the amount of MoS 2 located on the edges and corners per surface area of catalysts) and the density of Brønsted acid sites (C BAS , the amount of Brønsted acid sites per surface area of catalysts), respectively. Among all catalysts investigated, NiMo/A 30 Y 50 with 30 wt% Al 2 O 3 showed the best performance in selective hydrocracking reactions owing to its high C M o S 2 and C BAS , even in the presence of ammonia in the feed. The findings of this study will aid the development of selective hydrocracking catalysts with high performance at the industrial level. [ABSTRACT FROM AUTHOR]

[Display omitted] • In 2 O 3 has been used as support, promoter and active center for catalytic CO 2 hydrogenation. • In 2 O 3 -based catalysts have outstanding activity, selectivity and stability to CO 2 hydrogenation. • Interfaces on In 2 O 3 -based catalysts are the most favorable for CO 2 adsorption and hydrogenation. Catalytic hydrogenation of CO 2 into valuable chemicals, e.g. CH 3 OH, has been among the greatest concerns for both scientific and industrial communities, due to its crucial role in solving the serious CO 2 -related problems. In 2 O 3 -based composite catalysts have attracted great attentions due to their outstanding activity, selectivity and stability towards CO 2 hydrogenation, in both thermocatalysis and photocatalysis. The present review summarizes the recent progress on In 2 O 3 -based composite catalysts for boosting CO 2 hydrogenation. Strategies for improving the performance of In 2 O 3 -based composite catalysts are discussed. Hydrogenation mechanisms of CO 2 on In 2 O 3 -based composite catalysts are analyzed. Future research opportunities and challenges are shown at the end of this review. The present review will stimulate more deep insights on In 2 O 3 -based composite catalysts for achieving more efficient CO 2 conversion. [ABSTRACT FROM AUTHOR]

• Dual bed catalyst strategy is proposed to boost hydrocracking performance for LCO. • Dual bed catalyst contains 50% fresh and 50% "used" Ni-Mo/HY-Al 2 O 3 catalysts. • The "used" catalyst exhibits superior mono-aromatics maintenance ability. • Dual bed catalyst shows superior octane number, C5+ yield and lower H 2 consumption. Processing of light cycle oil (LCO) by hydrotreating and subsequent hydrocracking process harbors tremendous significance due to more stringent environmental regulations and growing demand for high-octane gasoline. However, the commercial single bed hydrocracking catalysts normally over-saturate multi-ring aromatics in LCO, leading to increased H 2 /energy consumption and reduced octane number. Herein, novel dual bed catalyst strategy is first proposed to enhance the hydrocracking performance, which contains fresh and used Ni-Mo/HY-Al 2 O 3 catalysts as upstream and downstream bed catalyst, respectively. In order to select suitable downstream catalyst, the used industrial Ni-Mo/HY-Al 2 O 3 catalysts in reactor after running for almost 1 year were divided into almost 20 layers through sampling along the axial positions, and then systematically analyzed by multi-techniques, including XPS, HRTEM, Py-IR, TPD, TGA and XRD. It is found that the first 20% of all catalyst layers suffer from serious deactivation due to coke formation, leading to the loss of Ni-Mo-S phase and acidic sites. Employing this first 20% of used catalysts as downstream catalyst, the weaker hydrogenation performance could avoid excessive hydrogenation and maintain mono-aromatics content. As expected, the designed dual bed catalyst leads to superior octane number, higher liquid yield of C 5 + and lower H 2 consumption than the commercial single bed catalyst. This strategy not only offers a scenario to boost the hydrocracking performance, but also sheds new light on the efficient utilization of used catalyst. [ABSTRACT FROM AUTHOR]

• Co-Mo nanoparticles are impregnated with the addition of multi-hydroxyl compound. • Co-Mo-C/mesoporous γ-Al 2 O 3 catalyst is easier to be reduced. • More Co-Mo-S type II sites exist due to weak metal-support interaction. • 99.9% sulfur removal activity is achieved over 5000 h in a 3000 kt/a industrial plant. Ever-increasing concern on environmental impacts (e.g., sulfur pollution) by fossil fuels has triggered the research on hydrodesulfurization (HDS). In this work, Co-Mo nanoparticles were deposited on the mesoporous γ-Al 2 O 3 support with the addition of organic compound, and the physico-chemical properties of the catalysts (Co-Mo-C/mesoporous γ-Al 2 O 3) were then characterized by multi-techniques such as H 2 -TPR, HRTEM, XPS, N 2 physisorption. It is found that the Co-Mo-C/mesoporous γ-Al 2 O 3 catalyst is easier to be reduced when organic compound is added, enhancing the sulfuration. This results in better dispersion of Co-Mo-S species and more Co-Mo-S II active sites, which significantly enhance diesel ultra-deep hydrodesulfurization activity. Furthermore, this novel catalyst was also tested for HDS reaction in a 3000 kt/a industrial-scale plant. Gratifyingly, this catalyst showed effective reduction of sulfur content from 9000 to less than 10 μg/g and also high stability over 5000 h. The results are of great significance to the design and development of industrial HDS catalysts. [ABSTRACT FROM AUTHOR]

• A room-temperature process was developed to prepare catalyst for hydrodesulfurization reaction. • S content of diesel was reduced from 18000 μg g−1 to 3 μg g−1. • The catalyst showed an excellent long-term stability. • Excellent performance of the catalyst was originated from the appropriate sulfidation degree of Mo. By using a room-temperature discharge-based sulphurization (RT-DS) process, we efficiently tune sulfidation degree of metal on γ -AlOOH-supported NiMo catalyst via simply changing feedstock amount for preparing catalysts, thus preparing a NiMoS/AOH-4 catalyst for hydrodesulfurization (HDS) of diesel. NiMoS/AOH-4 shows an excellent HDS performance, with S content of diesel being reduced from 18000 μg g−1 to 3 μg g−1 and without catalytic efficiency decrease after 1000 h reaction. Moreover, NiMoS/AOH-4 shows higher rate constant, higher turnover frequency but lower activation energy in HDS reaction, as compared with those on widely reported catalysts. The excellent HDS performance of NiMoS/AOH-4 is resulted from the appropriate sulfidation degree of Mo, which creates more abundant catalytic active Ni-Mo-S phases. RT-DS process for preparing NiMoS/AOH-4 proceeds in Ar at room temperature and atmospheric pressure, without using H 2 S and heating. This makes RT-DS process suitable for large-scale industrial applications to fabricate more efficient HDS catalysts. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The Ni particle size of Ni/AlSBA-15 can be tuned by adjusting the Al content. • Semihydrogenation of phenylacetylene (PA) over Ni/AlSBA-15 is structure-sensitive. • NiZn and NiGa alloys were formed on AlSBA-15 supported bimetallic catalysts. • NiZn 3 /AlSBA-15 showed 90.3% selectivity to styrene at nearly 100% conversion of PA. • NiZn 3 /AlSBA-15 displayed stable activity and selectivity over 100 h on-stream. Abstract A series of nonprecious monometallic Ni/AlSBA-15 and bimetallic Ni M (M = Zn, Ga, Cu, or Fe)/AlSBA-15 catalysts were prepared using a urea precipitation method and applied to the semihydrogenation of phenylacetylene. The catalysts were characterized by various techniques, showing that the Ni particle size of catalyst can be tuned by adjusting the Al content, and NiZn and NiGa supported catalysts exhibited geometric and electronic effects that originated from the bimetallic alloy. Among all the catalysts studied, NiZn 3 /AlSBA-15, with a turnover frequency of 10.89 s−1 comparable to that of precious Pd-based catalysts, presented the highest selectivity to styrene (90.3%) at nearly 100% conversion of phenylacetylene in semibatch operation. This catalyst was further evaluated in a continuous fixed-bed reactor for semihydrogenation of a model C 8 aromatic fraction of pyrolysis gasoline (a mixture of phenylacetylene, styrene, ethylbenzene and xylene), which aimed at assessing its practical application of recovering styrene from pyrolysis gasoline. The results showed that at complete conversion of phenylacetylene, the styrene concentration in the product was always kept at a stable level and higher than its initial concentration over 100 h of time on stream, demonstrating high selectivity and good stability of NiZn 3 /AlSBA-15. Finally, the application of NiZn 3 /AlSBA-15 was extended to other phenylacetylene derivatives. [ABSTRACT FROM AUTHOR]

[Display omitted] • The hydrolysis, oxolation and alcoxolation reaction processes were monitored. • Evolution of aluminum coordination environment was identified by DFT calculation. • Dominating factor for large pore formation of pseudo-boehmite was revealed. • Outstanding selectivity of n -heptane reforming was achieved on PtSn-Al 2 O 3 catalyst. The mechanistic understanding of the pore formation during aluminum alkoxide hydrolysis is of crucial importance for the controlled engineering of large pore volume pseudo-boehmite. The time-dependent structure evolution during n -hexanol-aluminum hydrolysis and the DFT calculations were performed to monitor the changes in the aluminum coordination. The results show that the hydrolysis, oxolation and alcoxolation reactions dominate the pore construction in turn with the continuous addition of water. The aluminum coordination undergoes aggregation from Al tetra -coordinates to Al hexa -coordinates and further stable Al 3 hexa -coordinates as repeating units for linear growth. The rate and amount of water injection is critical for the retention of at least one OR (R = -C 6 H 13) group, which acts as a directed pore-forming group to promote the large cyclization growth of the Al 3 hexa -coordinates. Consequently, 1.44 cm3/g pore volume of high-purity pseudo-boehmite was obtained, and the prepared PtSn-Al 2 O 3 catalyst exhibits a > 80 % of toluene selectivity for n -heptane reforming. [ABSTRACT FROM AUTHOR]

• The state-of-the-art strategies for the lignin conversion to alkanes over different multifunctional catalysts are summarized. • The depolymerization and hydrodeoxygenation process of lignin and lignin-derived compounds are detailed discussed. • The roles of different active metals for the catalysts and conversion of lignin to alkanes are described. • The major challenges and the future research trend in this field have been prospected. Lignin exists widely in nature and is a potential substitute for traditional fossil fuels. The technology of producing alkanes from lignin and its derivatives has been extensively studied in recent decades. This review summarizes state-of-the-art strategies for the conversion of lignin to alkanes over different multifunctional catalysts. The hydrodeoxygenation (HDO) process of lignin and lignin-derived compounds at different metal sites and the possible depolymerization pathways are detailed discussed. The roles of different active metals and their advantages for the catalysts and conversion of lignin to alkanes are also described. Finally, the major challenges and the future research trend in this field have been prospected. [ABSTRACT FROM AUTHOR]

• The influence of impregnation solutions with different acid-base properties on the surface structure of NiMo/Al 2 O 3 catalysts process was compared. • The main forms of Mo and Ni on the catalyst surface and the synergetic effect of surface structure were clarified. • Key factors leading to high product content of alkanes and monocyclic aromatic hydrocarbons and superior HDS and HDN performance over NiMo/Al 2 O 3 catalysts were explained. Two NiMo/Al 2 O 3 catalysts were prepared using impregnation solutions with different acid-base properties. And the effects of the surface structural differences on FCC diesel hydrotreating and desulfurization performance were investigated. XRD, Raman, H 2 -TPR, TEM, XPS characterization showed that NiMoO 4 and polymolybdates, the mainly metal phase on the surface of NiMo/Al 2 O 3 -A, would tend to form a three bridging hydroxyl structure with the γ-Al 2 O 3 support. The abundant NiMo alloy structures weakened the interaction between metal and oxygen atoms. While the NiMo/Al 2 O 3 -B with more developed specific surface area, pore volume and acid content tended to form double bridging hydroxyl structures, which had more active interactions with metals. The higher sulfidation degree of NiMo/Al 2 O 3 -B could be observed, exhibiting more NiMoS structures and stronger metal synergetic effects. The performance evaluation results showed that NiMo/Al 2 O 3 -A had better desulfurization and denitrification performance, and the content of S and N in the diesel decreased to 211 μg/g and 96.3 μg/g, respectively, which was attributed to the more active phases brought about by the good MoS 2 dispersion. On the other hand, NiMo/Al 2 O 3 -B exhibited better hydrotreating performance, with the content of alkanes and monocyclic aromatic hydrocarbons in the product increasing from 20.5% and 24.2% to 33.6% and 48.7%, respectively. The higher content of alkanes and monocyclic aromatic hydrocarbons provided a wider range of application for FCC diesel after upgrading. [ABSTRACT FROM AUTHOR]

• Pore structures of HDM catalyst pellets were optimized at the reactor scale. • Reactor-pellet coupling model based on hierarchical pore structures was adopted. • Relationship of the diffusivity with the macropore structure was established. • Mesopore-dependent concentration gradient along the reactor was proposed. Probing the effects of hydrodemetallization (HDM) catalyst pore structures is of great importance. In this work, the pore structures of hierarchically structured HDM catalyst pellets are optimized based on a Random Spheres Model at the reactor scale. Understanding of the metal deposition behaviors and the concentration profiles along the reactor indicates strong macropore-dependent catalyst pellet utilization and mesopore-dependent bed utilization, respectively. Subsequently, relationships of the effective diffusivity with the macropore structure and the concentration gradient along the reactor with the mesopore structure are proposed, and the effects of the macro-/mesopore diameters and porosity are studied to maximize the exit conversion and catalyst lifetime. Our optimized results not only are superior to previously optimized results, but also provide rational interpretations for previous experimental observations. The insights revealed here could shed new light on the rational pore engineering of the hierarchical structured HDM catalysts. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • First evidence showing that Fe 3 O 4 morphology affects aquathermolysis performance. • L-Fe 3 O 4 with irregular morphology has larger intercrystalline mesopores. • Larger mesopores break C–S bonds and decrease resin/asphaltene content. • Synergy between Fe 3 O 4 NPs and heulandite can decrease the size of Fe 3 O 4. • Fe 3 O 4 /heulandite catalyst can effectively reduce viscosity of crude oil by 85%. Abstract Elucidating the underlying structure-performance relationship of Fe 3 O 4 -containing catalysts for the aquathermolysis of crude oil is essential for the design of efficient heterogeneous catalysts. Therefore, recyclable Fe 3 O 4 nanoparticles (NPs) with different morphology and particle size were first prepared and tested for catalytic aquathermolysis. The easily prepared Fe 3 O 4 NPs with irregular morphology (L-Fe 3 O 4) have larger intercrystalline mesopores than oleic acid-modified Fe 3 O 4 NPs. This leads to enhanced mass transfer ability, more accessible active sites and thus better aquathermolysis performance. Moreover, these L-Fe 3 O 4 NPs were loaded on a heulandite support by a scalable co-precipitation method, and this L-Fe 3 O 4 /heulandite catalyst showed very good performance in catalytic aquathermolysis, with a viscosity decrease of extra-heavy crude oil of 85.0%. The underlying structure-performance relationship was systematically investigated by XRD, HRTEM, EDX-mapping, FT-IR, elemental analysis, SARA (saturate, aromatic, resin and asphaltene) analysis and 1H NMR. The Fe 3 O 4 /heulandite catalyst broke C–S bonds and reduced the resin and asphaltene content of the oil. This work is important for the design of Fe 3 O 4 -containing catalysts in catalytic aquathermolysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Finely tuning on the structures of NaY zeolite is achieved by simply changing crystallization times. • The NaY zeolite triggers more efficient separation of the photogenerated electron-hole pairs. • The NaY zeolite leads to enhanced visible-light-driven photocatalytic H2 production from H 2 O. • Outstanding photocatalytic stability is obtained in the presence of the NaY zeolite. Photocatalytic H 2 production from H 2 O is promising for solving the energy and environment problems. Zeolites have been widely used in thermocatalysis, but their application in photocatalysis is limited. Herein, we anchor CdS and Pt nanoparticles on a NaY zeolite (ZP48) fabricated via 48 h crystallization to form a CdS/Pt/ZP48 photocatalyst for visible-light-driven photocatalytic H 2 production from H 2 O. CdS/Pt/ZP48 shows a H 2 production rate (686.5 μmol h−1) which is higher than those on Pt/CdS (263.2 μmol h−1) and photocatalysts with zeolite supports prepared by using crystallization times shorter and longer than 48 h, with an apparent quantum efficiency of 23.5% and superior stability. ZP48 promotes the separation of photogenerated electron-hole pairs, thus releasing more electrons for enhancing the photocatalytic H 2 production on CdS/Pt/ZP48. These results are helpful for fabricating more efficient photocatalysts by zeolites which are widely used in industry but have poor ability in light absorption and charge transfer. [ABSTRACT FROM AUTHOR]

• B 4 C was used as a novel metal-free catalyst for aerobic oxidative desulfurization. • By using ball-milled B 4 C as the catalyst, 99.5 % of sulfur removal was achieved. • The catalyst can be recycled for 17 times. • The catalyst showed ∼90 % of desulfurization performance in real diesel. Metal-free catalysts have been proved to be a low-cost and environmentally friendly species in aerobic oxidative desulfurization (ODS). In this work, exfoliated metal-free boron carbide with few-layered structure, small size, and abundant defects, was first employed in an aerobic ODS system for ultra-deep desulfurization. The exfoliation process was realized by employing a planetary ball mill strategy. Detailed characterizations showed that the ball milling process not only induces thinner layers and small sizes but also introduces numerous defects into the boron carbide catalysts, which is vital in metal-free catalysis. Furthermore, the exfoliated boron carbide catalyst was applied in aerobic ODS system, and 99.5 % of sulfur removal was obtained. Moreover, the catalyst can be recycled 17 times without a significant decrease in catalytic activity. In particular, it was found that ∼90 % of the sulfur compounds in real diesel oil could be removed by the current aerobic ODS system. [ABSTRACT FROM AUTHOR]