Ni Loading Amount Research Articles

Unveiling the catalytic performance of unique core-fibrous shell silica-lanthanum oxide with different nickel loadings for dry reforming of methane

The dry reforming of methane (DRM) stands as a remarkable process for the conversion of methane and carbon dioxide into syngas (H2/CO). In this study, mesoporous fibrous silica lanthanum oxide-supported nickel catalysts (NSLF-x) with various nickel loadings (3 to 15 wt%) were efficiently fabricated using the microemulsion and impregnation approaches, respectively, to conduct DRM. The results obtained from FESEM and TEM revealed the presence of a unique core-fibrous shell-structured morphology of silica lanthanum oxide support (SLF). Furthermore, XRD and SEM-EDS analyses indicated that the structural integrity of SLF remained consistent regardless of the amount of Ni loading, while the size of NiO nanocrystalline varied with the quantity of Ni loading. Notably, H2-TPR analysis emphasized that the NSLF-15 catalyst exhibited the strongest metal-support interaction among the catalysts. Due to this reason, it exhibited outstanding catalytic activity and stability in terms of CO2 conversion (86.7 %), CH4 conversion (87 %), and a high H2/CO ratio at 750 °C, demonstrating high thermal stability after 28 h without any signs of deactivation. The superior catalytic performance of NSLF-15 catalysts, along with their ability to activate CH4 and CO2, can be attributed to the synergistic effects resulting from the enhanced physicochemical properties and the unique morphology. Additionally, the results from TEM, Raman, and TGA analyses also indicated the presence of non-filamentous carbon and filamentous carbons with accumulation of Ni species due to the elevated temperature of the reaction. Overall, the NSLF-15 catalysts hold significant potential for industrial-scale application for syngas formation.

Ni-doped metal-azolate framework-6 derived carbon as a highly active catalyst for CO2 conversion through the CO2 hydrogenation reaction

A profound and accelerated solution towards mitigating atmospheric CO2 levels and converting the CO2 to useful fuels and chemicals, such as CO or CH4, would be to utilize and promote the catalytic CO2 hydrogenation reaction. To optimize this process, high-performance catalysts and favorable conditions must be identified. This study incorporated Ni-doped MAF-6 (containing Zn, N and C) derived carbon-supported catalysts synthesized by in-situ impregnation. By varying the Ni loading amount (1–4 wt.%) and the pyrolysis temperature (600–900 °C), this determined as to how the nanomaterial structures and interactions can tune the reaction performance. Based on BET, PXRD and XPS characterization tests, the carbon structure was porous with highly dispersed and embedded Ni generated by a strong interaction between Ni and Zn-N-C in the MAF-6-derived carbon material, especially as the increasing pyrolysis temperatures evaporated more Zn. From this, CO2 hydrogenation catalytic tests were carried out at 500–800 °C and 100 mL min−1 flow at a H2: CO2 ratio of 3:1. Based on the key structural and material properties, the MAF-64Ni,600 catalyst (i.e., 4 wt.% Ni loading, 600 °C pyrolysis) proved to be optimal, displaying 59% CO2 conversion and 100% CO selectivity at 650 °C. Most of the catalysts formed no CH4 due to the low loading of Ni.

One-pot fabrication of waste granular silica gel (WGSG) supported nickel catalysts for dry reforming of methane

The waste granular silica gel (WGSG) was reused as nickel-based catalyst support, where the innovation could be reflected in the following aspects: recycling the SiO2 resources to reduce catalyst cost and utilizing the granular shape to skip catalyst molding. The Ni/WGSG catalysts were prepared by a facile one-pot impregnation method and further tested in the dry reforming of methane (DRM) reaction. The physico-chemical properties of the catalysts were also characterized by XRD, H2-TPR, TGA, SEM and TEM. It was found that among the three catalysts with different Ni contents, the Ni/WGSG-2 with medium Ni loading amount showed a comprehensively better activity towards DRM. Under the condition of CO2/CH4 = 1:1 and 900 °C, the CO2 and CH4 conversion of Ni/WGSG-2 catalyst could reach 83.6% and 69.5%, respectively, due to its better anti-coking and anti-sintering ability than the other two catalysts. The stability test with varying working conditions showed the Ni/WGSG-2 catalyst can function steadily for 30 h without large deactivation and its average activity is comparable to several Ni catalysts using complex substrates such as carbonized materials and core-shell SiO2. The mechanism investigation via in-situ DRIFTS disclosed that in the process of DRM reaction, consecutive decomposition of adsorbed CH4 molecule to CHx fractions and further to C species was the prerequisite to initiate the reaction and the presence of CO2 could accelerate the above process by forming bridged carbonyls as reaction intermediate.

High-yield H2 production from polypropylene through pyrolysis-catalytic reforming over activated carbon based nickel catalyst

With the aggravation of energy crisis and environmental pollution, green and renewable new alternative energy has become the focus of global attention. Hydrogen energy has become an important part of the global energy pattern in the future. Conversion of solid waste plastics into hydrogen energy by pyrolysis/gasification is a promising solution. This study aims to explore a method of high-yield in hydrogen by breaking down polypropylene, a cheap and efficient nickel catalyst is prepared and applied to the experimental study of hydrogen production by pyrolysis-catalytic reforming. The effects of catalytic temperature, Ni loading (%) and catalyst addition amount on hydrogen production of catalyst were investigated, the hydrogen production was increased by introducing water vapor. Under the optimized reaction parameters (catalytic temperature 900 °C, PP to catalyst ratio 1:0.75, Ni loading 15 wt%), the hydrogen yield is up to 40.24 mmol/gPP without water and 134.91 mmol/gPP with water, the addition of water significantly increased hydrogen production. this results have obvious advantages in hydrogen production compared with similar studies. Furthermore, the existence of various forms (snake-like, straight carbon nanotubes and carbon nanospheres) of carbon deposition found in this paper can provide new ideas for researchers working on graphite carbon. This study provides an effective new approaches for enhancing hydrogen production by pyrolysis/gasification of waste plastics.

Hydrogen production from supercritical water gasification of lignin catalyzed by Ni supported on various zeolites

In the present study, supercritical water gasification of dealkaline lignin catalyzed by Ni supported on different zeolites (3A, 4A, 5A, 13X and ZSM-5) was investigated. Scanning electron microscopy-energy dispersive X‐ray spectrometry (SEM-EDS), N2 adsorption–desorption and X-ray diffraction (XRD) were used to characterize the catalyst. Most of these catalysts enhanced the gasification except Ni/ZSM-5, and the order of their catalytic activity was: Ni/4A > Ni/3A > Ni/5A > Ni/13X > Ni/ZSM-5. The higher activity of Ni/4A was probably because it has mesopores with proper size to disperse Ni and provide more active sites for the reaction. With the catalysis of Ni/4A, the hydrogen selectivity was increased from 27.07% to 42.61%, and the H2 yield increased from 3.14 mol/kg to 5.63 mol/kg. With Ni/4A, the prolongation of reaction time improved the gasification efficiency and hydrogen production, but its impact became less pronounced when it was above 20 min. The increase of the Ni loading amount from 0 to 30 wt% in Ni/4A improved the hydrogen yield by 1.9 times to 6.2 mol/kg, but its further increase from 30 wt% to 50 wt% had less influence.

Optimized nano-metal particles filled into carbon nanohorns to achieve high N-doping amount and high porosity for enhanced oxygen evolution reaction.

Nano-metal-filled N-doped carbon materials have been actively verified as promising alternatives for precious-metal catalysts in the oxygen evolution reaction (OER). Herein, Ni/Fe/Cu-filled N-doped carbon nanohorns (CNHs) are synthesized via a positive pressure assisted arc discharge method using a Ni/Fe/Cu rod charged in an anode hole in a N2 and Ar mixture. We first found that the amount of N atom doping can be controlled by the types of nano-metal particles encapsulated by CNHs. The content of N atoms on CNHs uniquely depended on the initial Ni wires inserted into the anode graphite; increasing the number of Ni wires induced the enrichment of N atoms until 3.56 at%, whereas the content of N atoms for Cu- and Fe-filled CNHs is against the results; loading Cu and Fe nanoparticles decreases the N-doping amount. And the morphologies and N-configurations can be changed by the types of metal nanoparticles. Furthermore, the OER performance of Ni-filled CNHs is much superior to that of Cu- and Fe-filled CNHs, which can be significantly enhanced by the tip opening structure, and the increase in Ni loading amount and the N atom content.

Highly dispersed PtNi nanoparticles modified carbon black as high-performanced electrocatalyst for oxygen reduction in acidic medium

• Rational optimization of Ni/C precursor for Pt galvanic replacement. • Regulation on the electronic structure of active site stemmed from PtNi alloys. • PtNi/C shows excellent and stable ORR activity via 4e - pathway in acidic medium. • The mass activity of PtNi/C at 0.8 V is 9.4 times that of commercial Pt/C. Due to the excellent intrinsic activity, platinum-based materials are widely used to produce highly efficient electrocatalysts towards oxygen reduction reactions (ORR), but their ultrahigh price and poor stability severely hinder the mass production and further wide application. Alloying Pt with 3d transition metals through galvanic replacement is an effective way to reduce Pt loading based on the premise of outstanding ORR activity. In this work, to fabricate the optimal precursor for subsequent galvanic replacement, a series of carbon-supported Ni samples were firstly prepared by tuning the Ni loading amount and pyrolysis temperature. Then, the highly dispersed PtNi nanoparticles modified carbon nanohybrid (PtNi/C) with low Pt content of 2.29 wt% can be obtained, which exhibits remarkable and durable ORR activity with E 1/2 of 0.841 V vs. RHE via efficient 4e - ORR process in acidic media. Moreover, it should be emphasized that the as-synthesized PtNi/C behaves the impressively high mass activity of 0.57 A/mg Pt at 0.8 V, which is 9.4 times that of commercial Pt/C. It is confident that our work can offer constructive suggestions for the design and synthesis of high-performanced electrocatalysts fabricated through galvanic replacement method.

Deoxygenation of non-edible fatty acid for green diesel production: Effect of metal loading amount over Ni/MgO–Al2O3 on the catalytic performance and reaction pathway

Ni/MgO-Al2O3 (Ni/MG70) catalysts were developed for the deoxygenation reaction to produce green diesel from non-edible fatty acids. As the Ni loading amount was increased from 5% to 30%, the characteristics of the catalysts, such as Brunauer–Emmett–Teller (BET) surface area, Ni dispersion, reducibility, number of Ni active sites, and acidity, varied. Among the prepared catalysts, the 20% Ni/MG70 catalyst showed excellent deoxygenation performance owing to its highest number of Ni active sites, easier reducibility, and appropriate acidity. Furthermore, it was confirmed that deoxygenation in this study was carried out via the hydrodeoxygenation reaction pathway to remove oxygen species as H2O. In addition, the basic fuel properties, calorific value and viscosity, were analyzed for produced green diesel.

Catalytic steam reforming of real tar under high-efficiency Ni/USY catalyst for H2 production

A series of Ni/USY catalysts were developed by incipient wetness impregnation and applied for catalytic steam reforming of coal tar in a two-stage reactor. The reforming conditions, including Ni loading amount (5–20 wt%) and reaction temperature (600–900 °C), were studied. It was found that Ni/USY catalyst showed a superior catalytic activity in terms of tar conversion (81.3%) and H2 yield (87.2 mmol/g) when the Ni loading amount was 15 wt% (i.e. 15NiY) and reaction temperature was 800 °C. The performance of 15NiY in terms of tar conversion decreased slightly after 180 min of reaction and could be recovered easily. According to N2 adsorption-desorption analysis, as-prepared catalysts exhibited excellent porosity and the special surface area was higher than 450 m2/g. Ascribed to the high porosity and special structure of Ni/USY, Ni nanoparticles with a size of 10–50 nm were well dispersed, which was observed by XRD and FE-SEM/EDS. H2-TPR demonstrated the strong metal-support interation of Ni/USY catalysts. The XPS spectra demonstrated that the surface of Ni/USY catalysts were enriched with surface adsorbed oxygen species and the value of Ni0/Ni2+ reached the highest for 15NiY, which facilitated the extent of reaction. In addition, a kinetic model was applied for calculation of apparent activation energy and pre-exponential factor, which were 57.6 kJ/mol and 8.76 × 103 m3 kg−1catalyst h−1, respectively, indicating the effectiveness of Ni/USY catalyst.

Improving the Bio-Oil Quality via Effective Pyrolysis/Deoxygenation of Palm Kernel Cake over a Metal (Cu, Ni, or Fe)-Doped Carbon Catalyst.

Waste palm kernel cake (WPKC) is being utilized as a biomass feedstock for the sustainable production of catalysts/supports and bio-oil fuels. Herein, metal (Cu, Ni, and/or Fe)-doped carbon catalysts were prepared using conventional impregnation and pyrolysis methods. The physicochemical properties of the as-prepared catalysts were analyzed. According to the obtained results, the catalyst acidity was highly increased with the increase in the metal loading amount on a carbon support, leading to a better performance for deoxygenation/aromatization. A maximum yield of bio-oil from WPKC pyrolysis was achieved up to ∼60% under optimum conditions determined via statistical designs. From the results of bio-oil compositions, 15%Ni loading on activated carbon exhibited the best performance of about 72% for the production of hydrocarbon compounds. Monoaromatic hydrocarbons such as benzene, toluene, and xylenes (BTXs) could be reduced via condensation and polymerization with the increase of the Ni-loading amount. Moreover, the catalytic performance of the selected 15%Ni-carbon catalyst was also compared with those of commercial catalysts zeolite and alumina, and the results showed that the 15% metal-doped carbon catalyst presented much better stability/reusability for five times with less reduction of the hydrocarbon yield in the upgraded bio-oil. This research provided an eco-friendly strategy for the low-cost production of bio-oil fuel with a high quality/yield from waste biomass pyrolysis.

Preparation of Metal Modified onto Biochar from Hazardous Waste for Arsenic Removal.

Use of urban sludge, hospital sludge, and aquatic product sludge as a biochar adsorbent from wastewater treatment plants was investigated. Microwave carbonization was used to carbonize the sludge and then chemically activated at high temperatures to increase porosity and surface area. Effective of arsenic adsorption in water presents a newly designed metal doped to biochar. The biochar was characterized by scanning electron microscope (SEM) with energy dispersive X-ray (EDS), nitrogen adsorption/desorption isotherm analyzer (BET), thermo gravimetric analysis (TGA) and X-ray diffraction (XRD) analysis. Results display uniform pore sizes and high surface area (>490 m²g-1) of the biochar. Thence, urban sludge, hospital sludge, and aquatic product sludge can be used as carbon sources. The highest amount of Fe, Mn, and Ni loading onto the biochar was determined to be 8.0%, 6.0% and 10.0%, respectively. All biochar samples have arsenic adsorption capacities positively correlated with initial concentration. The corresponding removal efficiency of As(V) is 98% and As(III) is 84% at pH 3 with an adsorption capacity of 4.12 and 3.6 mg g-1, respectively. The adsorption capacity of As(V) and As(III) clearly decreased in the presence of PO₄3- (2.34 and 1.46 mg g-1, respectively). Due to competition for adsorption sites, the PO₄3- can effectively reduce arsenic adsorption. The arsenic species adsorption-desorption recycles on biochar are also discussed.

Nickel supported over MCM-41 coated ceramic membrane for steam reforming of real tar

A novel catalyst, Nickel supported over MCM-41 coated ceramic membrane (NMC), was developed using coating method and deposition-precipitation method and applied for steam reforming of real tar in fixed bed. The effects of reaction conditions such as Ni loading amount, reaction temperature and mass ratio of steam to tar were also studied. The good dispersion of Ni nanoparticles and the strong interaction between Ni particles and the support were identified by BET, XRD, H2-TPR and SEM/EDS, resulting in the excellent performance of NMC catalysts. Maximum tar conversion of 96.4% and H2 yield of 98.7 mmol g−1 were obtained using 20NMC with a mass ratio of steam to coal tar of 2 at 800 °C. Moreover, 20 NMC exhibited a good stability in 10 h of lifetime test and the resistance of graphitic carbon formation prone to easier regeneration of catalysts illustrated by Raman spectroscopy. It indicates that the utilization of NMC catalysts for tar steam reforming is a promising way.

Guerbet Reactions for Biofuel Production from ABE Fermentation Using Bifunctional Ni-MgO-Al2O3 Catalysts

To upgrade biomass-derived alcohol mixtures to biofuels under solvent-free conditions, MgO–Al2O3 mixed metal oxides (MMO) decorated with Ni nanoparticles (Ni–MgO–Al2O3) are synthesized and characterized. Based on the result, Ni nanoparticles are highly dispersed on the surface of MgAl MMO. As the Ni loading content varies from 2 to 10 wt.%, there is a slight increase in the mean Ni particle size from 6.7 to 8.5 nm. The effects of Ni loading amount, reducing temperature, and Mg/Al ratio on the conversion and product distribution are investigated. With the increase in both the Ni loading amount and reducing temperature, dehydrogenation (the first step of the entire reaction network) is accelerated. This results in an increase in the conversion process and a higher selectivity for the dialkylated compounds. Due to the higher strength and density of basic sites under high Mg/Al ratios, double alkylation is preferred and more long-chain hydrocarbons are obtained. A conversion of 89.2% coupled with a total yield of 79.9% for C5–C15 compounds is acquired by the as-prepared catalyst (prepared with Ni loading of 6 wt.%, reducing temperature of 700 °C, and Mg/Al molar ratio of 3. After four runs, the conversion drops by 17.1%, and this loss in the catalytic activity can be attributed to the decrease in the surface area of the catalyst and the increase in the Ni mean particle size.

Preparation of a Ni/LaAlO3 catalyst and its application in catalytic pyrolysis of soybean straw for syngas production

A LaAlO3 carrier was prepared via the sol-gel method, and a Ni/LaAlO3 catalyst was prepared via the homogeneous precipitation method; this catalyst was used for the catalytic pyrolysis of soybean straw for syngas (H2 + CO) production. The analysis of the raw materials (straw) was performed via elemental analysis and industrial analysis. The support and catalyst were characterized and analyzed by X-ray fluorescence spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and N2 adsorption-desorption isotherms. The results illustrated that the NiO was uniformly loaded on the LaAlO3 surface. Furthermore, the effects of the Ni loading amount, pyrolysis temperature, holding time, and calcination temperature on the performance of the catalyst were studied. The results showed that the catalyst had the highest increase in production and concentration of H2 and CO when the Ni loading was 10 wt%, the calcination temperature was 500 °C, the reaction temperature was 800 °C, and the holding time was 20 min. Compared with the pyrolysis of straw without a catalyst, the yield of H2 and CO increased from 85 mL/g and 125 mL/g to 238.5 mL/g and 255 mL/g, respectively, and the concentration of H2 and CO increased from 23.5 vol% and 29.4 vol% to 43.1 vol% and 41.9 vol%, respectively.

Catalytic effect of Ni@rGO on the hydrogen storage properties of MgH2

Abstract Uniform-dispersed Ni nanoparticles (NPs) anchored on reduced graphene oxide (Ni@rGO) catalyzed MgH2 (MH-Ni@rGO) has been fabricated by mechanical milling. The effects of milling time and Ni loading amount on the hydrogen storage properties of MgH2 have been investigated. The initial hydrogen desorption temperature of MgH2 catalyzed by 10 wt.% Ni4@rGO6 for milling 5 h is significantly decreased from 251 °C to 190 °C. The composite can absorb 5.0 wt.% hydrogen in 20 min at 100 °C, while it can desorb 6.1 wt.% within 15 min at 300 °C. Through the investigation of the phase transformation and dehydrogenation kinetics during hydrogen ab/desorption cycles, we found that the in-situ formed Mg2Ni/Mg2NiH4 exhibited better catalytic effect than Ni. When Ni loading amount is 45 wt.%, the rGO in Ni@rGO catalysts can prevent the reaction of Ni and Mg due to the strong interaction between rGO and Ni NPs.

Catalytic Conversion of Levulinic Acid to γ-Valerolactone over Hierarchical AlPO4-5 Supported Nickel Catalysts

Catalytic conversion of biomass based platform chemicals to value added chemicals has attracted much attention recently. In this work, Ni-based catalysts were developed for the conversion of levulinic acid to γ-valerolactone. By investigation of reduction behavior of NiO, it was found that a relatively low reduction temperature (300°C) can provide the reduction of NiO to Ni0. The high reduction temperature (500°C) generally applied in literature is not necessary. The effect of supports was also studied, and hierarchical AlPO4-5 (AlPO4-5-meso) supported Ni showed the best catalytic performance due to the proper pore size of AlPO4-5-meso, which contains both micropores and mesopores. The effect of Ni loading was also investigated, 10 wt % of Ni is enough for this reaction, which is lower than the reported amount of Ni loading. By using Ni/AlPO4-5-meso with 10 wt % Ni as catalyst, 84% γ-valerolactone yield and 100% levulinic acid conversion can be obtained after reaction for 10 h at 180°C.

Effect of Surface Composition and Structure of the Mesoporous Ni/KIT-6 Catalyst on Catalytic Hydrodeoxygenation Performance

A series of Ni/KIT6 catalyst precursors with 25 wt.% Ni loading amount were reduced in H2 at 400, 450, 500, and 550 °C, respectively. The studied catalysts were investigated by XRD, Quasi in-situ XPS, BET, TEM, and H2-TPD/Ranalysis methods. It was found that reduction temperature is an important factor affecting the hydrodeoxygenation (HDO) performance of the studied catalysts because of the Strong Metal Support Interaction Effect (SMSI). The reduction temperature influences mainly the content of active components, crystal size, and the abilityfor adsorbing and activating H2. The developed pore structure and large specific surface area of the KIT-6 support favored the Ni dispersion. The RT450 catalyst, which was prepared in H2 atmosphere at 450 °C, has the best HDO performance. Ethyl acetate can be completely transformed and maintain 96.8% ethane selectivity and 3.2% methane selectivity at 300 °C. The calculated apparent activation energies of the prepared catalysts increased in the following order: RT550 > RT400 > RT500 > RT450.

Enhanced dielectric performance of P(VDF-HFP) composites filled with Ni@polydopamine@BaTiO3 nanowires

Dielectric polymer nanocomposites have been attracting increasing attention because of their wide range of applications in electronics industry. To improve their dielectric properties, incorporating conductive fillers and ceramic fillers into the polymer matrix is considered to be an effective solution. Here, Ni nanoparticles (about 50–90 nm) were decorated onto the surface of polydopamine (PDA) coated BaTiO3 nanowires to synthesize Ni@polydopamine@BaTiO3 nanowires (Ni@PDA@BT NWs, also denoted as NPB) with different Ni loading amount. The nanowires were then added into poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) matrix and composite films were prepared. The dielectric performance of composite films is largely enhanced owing to the microcapacitor effect and interfacial polarization effect induced by Ni nanoparticles. This enhancement can be improved by increasing the loading amount of Ni. Crystallization behavior of the films were also investigated. With 20 vol% of Ni@PDA@BT NWs added, the dielectric constant of the composite film reaches 48.4 at 1 kHz, in contrast to 29.5 for 20 vol% of BT and 10.6 for pristine P(VDF-HFP). And the dielectric loss tangent remains at a low level of 0.23 at 1 kHz. These composite films exhibit potential for applications in flexible electronic devices and electrical systems.

Bimetallic Au–Ni alloy nanoparticles in a metal–organic framework (MIL-101) as efficient heterogeneous catalysts for selective oxidation of benzyl alcohol into benzaldehyde

Supported bimetallic nanoparticles (NPs) are extensively used as efficient oxidation catalysts. A series of Au–Ni bimetallic alloy NP catalysts with Au:Ni mole ratios varying from 1:0.35 to 1:4.76 was successfully synthesized via impregnation and H2 reduction. The catalysts are supported by a metal–organic framework MIL-101. For comparison, monometallic Au/MIL-101 with an Au loading amount of 2.97 wt% and Ni/MIL-101 with a Ni loading amount of 2.11 wt% were also prepared. The catalysts were thoroughly characterized through X-ray diffraction, N2 adsorption–desorption isotherms, transmission electron microscopy (TEM), scanning TEM with line mapping energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma atomic emission. Characterization results suggested that the AuNi bimetallic NP catalysts were homogeneously deposited on the MIL-101 surface, and an AuNi alloy structure was formed. The bimetallic Au–Ni and monometallic catalysts were evaluated for the oxidation of benzyl alcohol under O2 atmosphere. The bimetallic AuNi/MIL-101-1 catalyst displayed a higher catalytic activity under identical conditions compared with the monometallic catalysts due to the synergistic effects between Au and Ni metals. The Au–Ni/MIL-101-1 catalyst with an Au–Ni mole ratio of 1:0.35 exhibited the highest turnover frequency value of 15.4 h−1 for the oxidation of benzyl alcohol. In addition, the bimetallic AuNi/MIL-101-1 catalysts could be recovered easily by centrifugation and used repetitively for at least four times. These features make the catalysts particularly attractive in benzaldehyde synthesis.

Hydrodeoxygenation of methyl laurate over the sulfur-free Ni/γ-Al2O3 catalysts

A series of sulfur-free Ni/γ-Al2O3 catalysts with different metal Ni loading amount were prepared by impregnation method. The prepared catalysts and corresponding precursors were investigated through XRD, BET, H2-TPD, and H2-TPR analysis methods. The effect of Ni loading on catalytic performance of Ni/γ-Al2O3 catalysts was evaluated by methyl laurate catalytic hydrodeoxygenation (HDO). Results indicate that the catalytic HDO performance of the prepared Ni/γ-Al2O3 catalysts was directly related to hydrogen storage properties, hydrogen desorption properties, dispersion of the active component Ni, and so on. The 10 wt.% Ni/γ-Al2O3 catalyst exhibits the best HDO performance, and the methyl laurate conversion can reach 91.1% when the reaction temperature is 400 °C and pressure is 2 MPa. The HDO products are alkanes, such as C<10, C10, C11, C12 alkane, C12 alcohol, and C12 acid, especially. The main product C11 alkane with one carbon less is formed by decarbonylation/decarboxylation, and selectivity can reach 68.6%. The effects of reaction conditions on HDO reaction of oils were studied, for example, reaction pressure and H2/Oil ratio. The catalyst retains comparable activity upon regeneration through calcinations and H2 reduction.