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The aim of this study is to achieve the hydro-liquefaction of asphaltene for the production of liquid fuel. The oil soluble molybdenum catalysts, molybdenum dialkyl dithiophosphate, and nickel carboxylate precursor with different carbon chains, were synthesized. The catalysts were characterized by ICP-OES, TEM and XPS. Their catalytic performance for the hydro-liquefaction of asphaltene to liquid fuels was investigated in a slurry bed reactor by using decalin as hydrogen donor and dispersant. The results show that the bimetal catalytic system composed of molybdenum dialkyl dithiophosphate and caproic acid nickel produces more MoS2 and NiS x active species. The metal contents of which accounts for 81.8 and 81.0 wt% of the total amount of Mo and Ni, respectively, and thus exhibits the best catalytic performance among the catalysts studied. The liquid yield of the asphaltene hydrogenation over the bimetal catalyst is 84.6 wt%, which is much higher than that over other catalysts, and the coke content is only 8.6 wt% under the conditions of 1000 μg/g of total metal addition, 1:1 Mo/Ni metal mass ratio and 1:1 asphaltene/naphthalene mass ratio. The content of saturated and aromatic components in the liquid products of asphaltene hydrogenation of the bimetal catalyst system is 78.9 wt%, which is a high-quality liquid fuel component.

In this work, a new viral protein cage based nanoreactor was successfully constructed via encapsulating Tween 80 stabilized palladium nanoparticles (NPs) into rotavirus capsid VP2 virus-like particles (i.e. Pd@VP2). The effects of stabilizers including CTAB, SDS, Tween 80 and PVP on controlling the particle size of Pd NPs were investigated. They were further immobilized on graphene oxide (i.e. Pd@VP2/GO) by a simple mixing method. Some characterizations including FT-IR and XPS were conducted to study adsorption mode of Pd@VP2 on GO sheets. Their catalytic performance was estimated in the reduction of 4-nitrophenol (4-NP). Results showed that Tween 80 stabilized Pd NPs with the molar ratio of Pd to Tween 80 at 1:0.1 possessed the smallest size and the best stability as well. They were encapsulated into viral protein cages (mean size 49 ± 0.26 nm) to assemble confined nanoreactors, most of which contained 1–2 Pd NPs (mean size 8.15 ± 0.26 nm). As-prepared Pd@VP2 indicated an enhanced activity (apparent reaction rate constant kapp = (3.74 ± 0.10) × 10−3 s−1) for the reduction of 4-NP in comparison to non-confined Pd-Tween80 colloid (kapp = (2.20 ± 0.06) × 10−3 s−1). It was logically due to confinement effects of Pd@VP2 including high dispersion of Pd NPs and high effective concentration of substrates in confined space. Pd@VP2 were further immobilized on GO surface through C-N bond. Pd@VP2/GO exhibited good reusability after recycling for four runs, confirming the strong anchoring effects of GO on Pd@VP2. Graphic Abstract Electronic supplementary material The online version of this article (10.1007/s10562-020-03252-6) contains supplementary material, which is available to authorized users.

Ni/ZrO2–CeO2 catalysts with high loading of nickel have been prepared by coprecipitation method and employed to investigate the catalytic hydrodeoxygenation (HDO) performance of guaiacol. The mater...

High-loading NixPy catalysts supported on SiO2–TiO2 binary oxides with different Si/Ti atomic ratios were prepared by liquid-phase phosphidation using triphenylphosphine (PPh3) and valued for the h...

A wettability-controllable surface on carbon nanotubes (CNTs) was successfully constructed through directly grafting poly(N-isopropylacrylamide) (PNIPAM) from CNT surface (i.e. CNT-PNIPAM) via a facile method. The hybrid was employed as the support to prepare Pd catalyst (i.e. Pd/CNT-PNIPAM) for selective hydrogenation of cinnamaldehyde (CAL). The effects of thermoresponsive surface chemistry on catalytic performance were studied. Results showed that CNT-PNIPAM had the lower critical solution temperature (LCST) at about 37 °C. The hydrophilic surface of CNT-PNIPAM at 25 °C ( LCST), which exhibited the good adsorption properties for reactants in the reaction. The high Pd dispersion on Pd/CNT-PNIPAM as well as its good adsorption properties for CAL jointly resulted in an enhanced catalytic activity, meanwhile maintaining the selectivity to cinnamyl alcohol (COL) unchanged in comparison to CNT supported Pd catalyst (Pd/CNT).

A series of SiO2–TiO2 binary oxides supported high loading Ni catalysts were prepared using the co-precipitation method and tested in guaiacol hydrodeoxygenation (HDO). The catalysts were character...

Angewandte Chemie / International edition 60(12), 6807 - 6815 (2021). doi:10.1002/anie.202012816, Biomass‐derived 5‐hydroxymethylfurfural (HMF) is regarded as one of the most promising platform chemicals to produce 2,5‐dimethylfuran (DMF) as a potential liquid transportation fuel. Pd nanoparticles supported on N‐containing and N‐free mesoporous carbon materials were prepared, characterized, and applied in the hydrogenolysis of HMF to DMF under mild reaction conditions. Quantitative conversion of HMF to DMF was achieved in the presence of formic acid (FA) and H$_2$ over Pd/NMC within 2 h. The reaction mechanism, especially the multiple roles of FA, was explored through a detailed comparative study by varying hydrogen source, additive, and substrate as well as by applying in situ ATR‐IR spectroscopy. The major role of FA is to shift the dominant reaction pathway from the hydrogenation of the aldehyde group to the hydrogenolysis of the hydroxymethyl group via the protonation by FA at the C‐OH group, lowering the activation barrier of the C−O bond cleavage and thus significantly enhancing the reaction rate. XPS results and DFT calculations revealed that Pd$^{2+}$ species interacting with pyridine‐like N atoms significantly enhance the selective hydrogenolysis of the C−OH bond in the presence of FA due to their high ability for the activation of FA and the stabilization of H$^−$., Published by Wiley-VCH, Weinheim

A series of Cu catalysts supported on attapulgite (ATP) clay modified by Fe were synthesized by impregnation method and employed to investigate the catalytic performance for hydrogen production by methanol steam reforming (MSR) in the range of 240–315 °C. The physicochemical characteristics of Fe modified Cu catalysts supported on ATP were tested by N2 adsorption, XRD, SEM, H2-TPR, CO2-TPD and NH3-TPD. An excellent MSR activity, high methanol conversion and high selectivity of H2 with ignorable CO content, was achieved on Fe modified Cu/ATP catalysts. The presence of Fe promotes the reduction of CuO to metal Cu and improves the dispersion of Cu on ATP due to the synergistic effects between CuO and Fe2O3, which contribute to the high activity for MSR. ATP, as an easily available and cheap material, is a promising support of Cu-based catalysts for hydrogen production from methanol steam reforming.

TiO2-ZrO2 composite oxides with a series of different Ti/Zr atomic ratios were synthesized by using deposition precipitation method and employed as supports to prepare Ru catalysts. The physicochemical characteristics of Ru catalysts were tested by N2 adsorption, CO chemisorption, XRD, H2-TPR, SEM, TEM, NH3 adsorption and XPS and their catalytic hydrodeoxygenation (HDO) performance was evaluated by using guaiacol as a model compound. Ru/TiO2 catalyst exhibits low HDO activity due to the surface modification of Ru particles with Ti3+ species formed during the reduction of Ru/TiO2. The HDO activity of Ru catalysts was significantly promoted by ZrO2 in the supports because it can hinder the migration of Ti3+ species onto the surface of Ru particles and thus more Ru active sites are exposed. Higher selectivity of benzene for Ru catalysts supported on TiO2-ZrO2 composite oxides suggests that they are the promising supports for Ru catalysts in the HDO reaction of guaiacol.

Pd catalysts supported on TiO2 with different crystalline phases were prepared with formaldehyde as reducing agent and examined for hydrodeoxygenation (HDO) of guaiacol. Their properties were characterized by N2 adsorption, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. Compared to the carbon-supported Pd catalysts, TiO2-supported Pd catalysts exhibited higher C–O bond scission ability, which may be attributed to the presence of partially reduced titanium species originating from the reduction of Ti4+ by spillover hydrogen from Pd at 200 °C on the surface of TiO2. Guaiacol was hydrogenated on Pd sites to give 2-methoxycyclohexanol, which diffused to partially reduced titanium species and subsequently reacted with hydrogen from Pd to generate cyclohexane. Anatase TiO2-supported Pd catalyst gave the highest HDO activity of guaiacol among the Pd catalysts supported on three types of TiO2 (anatase, rutile, and their mix, P25), suggesting that more partially reduced ...

TiO2-modified Pd/SiO2 catalysts (TixPd/SiO2) have been prepared using wet impregnation and characterized with N2 adsorption, X-ray diffraction, transmission electron microscopy, and temperature-programmed reduction. Their catalytic performance was examined for hydrodeoxygenation (HDO) of guaiacol as a model component of bio-oil. A smaller Pd particle size was obtained by the addition of TiO2, which may contribute to the high conversion of guaiacol on TixPd/SiO2. A strong interaction between TiO2 and Pd occurred when the catalysts were reduced with H2 at 500 °C. TiOx covered on Pd particles can coordinate the oxygen atom in hydrogenation intermediates and activate the C–O bond that could contribute to the significantly enhanced deoxygenation activity. The results suggest that the catalytic HDO proceeds through hydrogenation of the benzene ring of guaiacol on Pd sites to form 2-methoxycyclohexanol, followed by deoxygenation on the sites at a reduced TiOx–Pd interface to generate cyclohexane.

MnO x catalysts were contrastively prepared by an alkali-promoted redox precipitation strategy (MnO x -RP) and a conventional citrate sol–gel method (MnO x -SG), and tested for the catalytic oxidation of toluene, where MnO x -RP exhibited higher catalytic activity, excellent catalytic durability under dry conditions and good regeneration ability under humid conditions. The characterizations results indicated that different crystalline phases but similar textual properties (specific surface area, porosity and morphology) were observed over MnO x -RP and MnO x -SG catalysts, while MnO x -RP presented significantly higher low-temperature reducibility and average oxidation state of Mn as well as higher abundance of surface adsorbed oxygen species compared with MnO x -SG, thus beneficially resulting in its superior catalytic activity in the reaction.

Molybdenum carbide (Mo2C) catalysts supported on mesoporous carbon (MC) were prepared by the carbothermal hydrogen reduction method. Their properties were characterized by N2 adsorption, XRD and TEM. The Mo2C formation procedure was investigated by TPR and XPS. Methyl stearate was employed as a model compound containing oxygen to investigate the hydrodeoxygenation (HDO) activity of Mo2C/MC catalyst. The results showed Mo2C was formed on MC at the reduction temperature up to 660 °C. The HDO of methyl stearate on Mo2C/MC catalyst occurred through two parallel routes to give the main product octadecane and the by-product heptadecane. 10 wt% Mo2C/MC catalyst exhibited high activity for HDO of methyl stearate with almost 100 % conversion of methyl stearate and high selectivity of 93.6 % toward octadecane, indicating that it is an excellent catalyst to convert vegetable oils into hydrocarbons.

The carbon-covered aluminas were prepared by using different monocarboxylic acids as carbon sources to modify active alumina, and then were used as supports to prepare supported CoMo catalysts for hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT). These monocarboxylic acid molecules can be readily converted to carbon species by thermal decomposition in a nitrogen atmosphere and deposited on an alumina surface. The carbon species can then effectively weaken the interaction between active metals and alumina, which improves the migration and growth of surface Mo species. This result further affected the morphology and orientation of surface sulfur species, that is, the slab length and stacking number of the MoS2 slabs, which closely relates to HDS activity. Since the surface Mo species supported on the alumina modified with acetic acid consisted of the MoS2 slabs with the shortest lengths, leading to the presence of more easily reducible sulfur species during the reaction, the corresponding catalyst exhibited the highest HDS activity for 4,6-DMDBT. In addition, the stacking numbers for all of the catalysts were relatively low, which hindered the adsorption of 4,6-DMDBT on the brim sites of the MoS2 stacks, and thus the HDS reaction mainly occurred through the direct desulfurization route.

A simple method to synthesize Zn 2+ doped poly(aniline- co - m -aminophenol) (PANMA), Zn-PANMA, for supercapacitors is reported. Capacitive behaviors of the copolymer based supercapacitor in 1 M H 2 SO 4 electrolyte were examined by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charge/discharge. The morphological characteristics of Zn-PANMA and PANMA doped with Fe 3+ and Cu 2+ were investigated by field emission scanning microscopy (FESEM), explaining the different capacitive behaviors of these transition metal ions doped PANMA. A specific capacitance of Zn-PANMA as high as 631 F g −1 was achieved at a current density of 0.5 A g −1 , due to the enhancement of the electrochemical properties of the copolymer by Zn 2+ doping. Moreover, the specific capacitance still remained 71.7% after cycling for 800 times, exhibiting a good cycling performance and structure stability of Zn-PANMA.

We report the synthesis of a promising carbon nanofiber–titania–cordierite monolith composite, i.e., CNF/TiO2/monolith, and its application as catalyst support in selective hydrogenation of cinnamaldehyde (CAL) to hydrocinnamic aldehyde (HCAL). The composite was synthesized through TiO2 coating on the surface of the monolith and the following CNF growth on it. Synthesized CNF/TiO2/monolith was subsequently employed to prepare its supported palladium catalysts, Pd/CNF/TiO2/monolith. Attachment strength and acid-resistant properties of the composite have been studied to evaluate its structural stability in some severe conditions. In addition, the effects of supported Pd particles, oxygen-containing surface groups, and internal diffusion limitation on catalytic performance over Pd/CNF/TiO2/monolith were further studied. Results revealed that the total BET surface area of the composite was 31 m2/g, and the macro- and mesopore structure dominated the pore space of the material (about 93%). Meanwhile, 94% of th...

A novel C/TiO2 composite supported palladium catalyst (Pd/C/TiO2) was prepared. The effects of the structural properties on the catalytic performance in citral hydrogenation were estimated from calculations and compared with a commercial activated carbon supported palladium catalyst (Pd/AC). The results showed that although the reaction rate was comparatively low over Pd/C/TiO2, which took approximately 24 h to reach 90% citral conversion, fourfold the time of Pd/AC, the selectivity for citronellal in citral hydrogenation remained high (approximately 85%) at the same citral conversion, while decreasing to 40% over Pd/AC. The comparatively lower reaction rate over Pd/C/TiO2 was attributed to the fewer surface Pd sites (3.94 μmol g−1 per cat) than on Pd/AC (12.2 μmol g−1 per cat). Further calculations discovered similar initial turnover frequency values over the two catalysts (approximately 0.1 s−1), which implied that citral hydrogenation is structure-insensitive over Pd catalysts and that crystallite size effects have little influence on the differences in the kinetics between the two catalysts. The high selectivity for citronellal over Pd/C/TiO2 was due to the negligible internal diffusion limitation inside the catalyst, which was proved by calculating the Weisz–Prater numbers (less than 0.3 of each reactant). In contrast, the pore structures, mainly composed of micro pores, caused serious internal diffusion limitation over Pd/AC, which finally led to the increase of the selectivity to the deeply hydrogenated product, 3,7-dimethyloctanol.

We reported the synthesis of a promising carbon–titania composite material, C/TiO 2 , and its application as the catalyst support in citral hydrogenation. The composite was synthesized by methane decomposition over formed TiO 2 using Ni–Cu as a catalyst. C/TiO 2 synthesized was subsequently employed to prepare its supported palladium catalyst, Pd/C/TiO 2 . The textural and structural properties of C/TiO 2 and Pd/C/TiO 2 were characterized by BET, SEM/EDS, TEM, ICP-AES, XRD and TG-DTG. The catalytic properties of Pd/C/TiO 2 were evaluated in selective hydrogenation of citral to citronellal. Results revealed that the addition of a little promoter Cu in composite synthesis helped to the improvement in textural and structural properties of C/TiO 2 . The optimal composite prepared had a BET surface area of 60 m 2 g −1 and 97% of its pore space were mesopore. It contained 38% of carbon composed of 90% of carbon nanofibers and 10% of amorphous carbon. Pd/C/TiO 2 prepared held the similar textural and structural properties as C/TiO 2 did. Although the comparatively lower catalytic activity caused by the lower palladium dispersion, Pd/C/TiO 2 exhibited the high citronellal selectivity (90%) at 90% citral conversion, which was attributed to the elimination of internal diffusion limitations due to its mesoporous structure.

A facile NiO–SiO 2 mixture intercalated clay with ordered porous structure was assembled via a novel intregallery interfacially controlled functionalization method is successfully established. The starting mesostructured silica-pillared clay is assembled by intragallery ammonia-catalyzed hydrolysis of tetraethoxysilane using cationic surfactant as gallery template, and subsequently, the formed porous clay precursor is combined with nickel–ammonia complex to obtain intragallery interfacially controlled functionalization of nickel oxide. The kind of structural transformation has been confirmed by elemental analyses, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), N 2 adsorption–desorption isotherms, DR UV–vis absorption spectra, temperature-programmed reduction (TPR), X-ray photoelectron spectrometer (XPS) and transmission electron microscopy (TEM). The results elucidate that most of the grafted nickel species was combined with Si–OH on the surface of gallery pores and other was incorporated into tetrahedral sites in the intragallery silica framework. The effect of in situ combined nickel–ammonia complex with porous clay precursor is an essential factor to direct the formation of the intragallery interfacially controlled functionalization. And the porous surface Si–OH takes the role decision for the functionalization process. By changing the concentration of nickel–ammonia complex during synthesis, the porous structure, surface area and scattering domain size is effected. Furthermore, the obtained solid materials exhibit excellent selective adsorption for thiophene from coking benzene. The formation mechanism of intragallery interfacially controlled functionalization is proposed.

A novel carbon-titania composite material, C/TiO2, has been prepared by growing carbon nanofibers (CNFs) on TiO2 surface via methane decomposition using Ni-Cu as a catalyst. The C/TiO2 was used for preparing supported palladium catalyst, Pd/C/TiO2. The support and Pd/C/TiO2 catalyst were characterized by BET, SEM, XRD and TG-DTG. Its catalytic performance was evaluated in selective hydrogenation of citral to citronellal, and compared with that of activated carbon supported Pd catalyst. It was found that the Pd/C/TiO2 catalyst contains 97% of mesopores. And it exhibited 88% of selectivity to citronellal at citral conversion of 90% in citral hydrogenation, which was much higher than that of activated carbon supported Pd catalyst. This result may be attributed to elimination of internal diffusion limitations, which were significant in activated carbon supported Pd catalyst, due to its microporous structure.

TiO2-containing bulk Ni2P catalysts (Tix-Ni2P) were prepared by coprecipitation and in situ H2 temperature-programmed reduction (TPR), and characterized by XRD, CO chemisorption, TEM, XPS, TPR, and NH3-TPD. Their hydrodenitrogenation performances were studied by using quinoline and decahydroquinoline (DHQ) as the model molecules. Both the hydrogenation and C−N bond cleavage activities of Ni2P were improved by the introduction of TiO2. The TiO2 species were mainly located separately on the surface of the catalysts and had strong interactions with surface Ni and P species. The reducibility of the precursors as well as the surface electronic properties of Ni2P catalysts were affected by the addition of TiO2. Tix-Ni2P showed higher CO uptake but less acid sites than Ni2P. The promoting effect of TiO2 was discussed by considering the electronic interactions between surface Ti and Ni2P species and changes in the adsorption geometries of quinoline, DHQ, as well as the partially hydrogenated intermediates over Ti...

A series of MCM-41-supported nickel phosphides with an initial Ni/P atomic ratio of 0.5−2 in the oxidic precursors were prepared by an in situ reduction method and characterized by X-ray diffraction (XRD), CO chemisorption, N2 adsorption, and transmission electron microscopy. Their catalytic performances were evaluated in the hydrodenitrogenation (HDN) of quinoline and compared with MCM-41-supported Ni−Mo sulfide. The supported nickel phosphides with initial Ni/P ratios of 1 or 1.25 exhibited much higher HDN activity than the supported Ni−Mo sulfide. XRD patterns of both high-performance phosphide catalysts revealed that the active phase was Ni2P. It is indicated that the HDN of quinoline on the MCM-41-supported nickel phosphides exclusively proceeds via a pathway, which involves fully saturated intermediates. The cleavage of the C−N bond in the decahydroquinoline is the rate-determining step in the HDN of quinoline on the supported nickel phosphides. In addition, the effects of H2S (CS2 as the precursor)...

Siliceous MCM-41-supported nickel phosphides from a precursor with a Ni/P atomic ratio of 3, 2, 1.25, 1, 0.5, or 1 / 3 were prepared by in situ reduction. A high heating rate and a multistep program were used to prepare the supported nickel phosphides. The in situ reduction method proved superior to the traditional reduction–passivation–rereduction method. The timely removal of local moisture from the surface during reduction is crucial to obtaining a high hydrodesulfurization (HDS) performance of the phosphide catalysts. The precursors were characterized by TPR to investigate the reactions involved in phosphide preparation, and the structures of the resulting nickel phosphides were characterized by means of 31P NMR and XRD. Nickel phosphide formation may start with the reduction of NiO to Ni, and the Ni metal may assist phosphide formation in the reduction of nickel-rich precursors. Nickel-rich phosphides exhibited much higher HDS activity than phosphorus-rich phosphides prepared by the in situ reduction method. Reduction of the precursor with Ni/P = 2 yielded Ni12P5/ MCM-41, whereas reduction of the precursor with Ni/P=1.25 produced Ni2P/MCM-41. As in the traditional reduction–passivation–rereduction method, a small excess of phosphorus in the precursors is also needed to obtain the desired nickel-rich phosphides by the in situ reduction method. Ni2P/MCM-41 was the most active catalyst in the HDS of dibenzothiophene among all of the supported nickel phosphides prepared by the in situ reduction method.

The kinetics of dibenzothiophene (DBT) hydrodesulfurization catalyzed by MCM-41-supported Co−Mo sulfides was investigated at temperatures of 280−340 °C and 5.0 MPa. Both the Langmuir−Hinshelwood (L−H) model and pseudo-first-order model were used to fit the experimental data in an integral operation. It was found that the L−H rate expression was not applicable in the study whereas the pseudo-first-order model fitted very well with the experimental data. Moreover, it is indicated that the L−H expression becomes first-order in DBT concentration if the adsorption of DBT is negligible and DBT concentration is low, as in a typical commercial hydrotreating process. It is shown that the rate constant of the hydrogenolysis route was influenced more greatly by the atomic ratio of Co to Mo than that of the hydrogenation route, implying that hydrogenolysis and hydrogenation might take place on separate active sites and the introduction of Co to the Mo matrix might enhance mainly the hydrogenolysis route.

A series of Ag–Pd/C catalysts with different Ag/Pd molar ratios were prepared by impregnation and characterized by N2 adsorption and XPS. The catalytic performance was investigated in the hydrodechlorination of carbon tetrachloride into chloroform. High selectivity toward chloroform, near 100%, was obtained over Ag–Pd/C bi-metal catalysts. A very pronounced surface enrichment with Ag in Ag–Pd/C catalysts determined by XPS may be responsible for the high selectivity of chloroform. It is suggested that hydrodechlorination of carbon tetrachloride into chloroform occurs on the surface of Ag in the Ag–Pd alloy and the role of Pd is to supply H atoms necessary.

A deep hydrodesulfurization (HDS) catalyst, which was considerably active to desulfurize dibenzothiophene (DBT) and 4, 6-dimethyldibenzothiophene (4,6-DMDBT), was prepared by depositing Ni-Mo species over SBA-15. The extremely high surface area of SBA-15 favors the dispersion of the active species, which result in very high HDS activity. The optimal Ni/Mo atomic ratio for this series of catalysts is 0.25. Ni-Mo(0.25)/SBA-15 exhibited excellent performance in HDS of DBT and 4,6-DMDBT.