Efficient Hydrodeoxygenation Research Articles

Supported Ru nanocatalyst over phosphotungstate intercalated Zn-Al layered double hydroxide derived mixed metal oxides for efficient hydrodeoxygenation of guaiacol

In this work, a strategy for rational design of high-performance heterogenous supported Ru nanocatalysts over mixed metal oxides for aqueous phase partial hydrodeoxygenation (HDO) of guaiacol in the batch reactor was developed taking advantage of supramolecular structure of Zn-Al layered double hydroxides (LDHs) with different interlayer anions. It was interestingly found that in the case of phosphotungstate intercalated ZnAl-LDH as the support precursor, strong interactions between Ru species and intercalated LDH-derived mixed metal oxide supports could be formed, in addition to the formation of surface reductive ZnWOx component and P-O species. Notably, as-fabricated supported Ru nanocatalyst showed much higher activity in the aqueous phase HDO of guaiacol to produce cyclohexanol at an extraordinarily low Ru/guaiacol molar ratio of 0.0009, along with a higher cyclohexanol yield of ∼86% under reaction conditions (250 °C, 2.0 MPa initial H2 pressure), compared to other two supported Ru ones over mixed metal oxides derived from tungstate- and nitrate-intercalated ZnAl-LDH precursors (cyclohexanol yield of 29.7 and 10.1%, respectively). Studies on structure-property correlations revealed that surface defective and acidic sites facilitated the activation of guaiacol and phenol intermediate, thereby enabling the catalyst with a strong ability to break Cring−OCH3 bond and promote the ring hydrogenation. This finding provides a promising way to tune surface structures of metal-based catalysts for the upgrading of biomass.

Efficient hydrodeoxygenation of lignin-derived bio-oil to hydrocarbon fuels over bifunctional RuCoWx/NC catalysts

Efficient hydrodeoxygenation of lignin-derived bio-oils to cycloalkanes was achieved over bifunctional RuCoWx/NC catalyst prepared by in situ pyrolysis method. The performance of RuCoWx/NC was investigated in HDO of 4-propylguaiacol, considering the influences of catalysts, initial H2 pressure, and reaction temperature. Catalyst screening reveals that RuCoW0.03/NC afforded the highest propylcyclohexane yield of 71.3% from 4-propylguaiacol at 220 ℃. At 240 ℃, the yield of propylcyclohexane increased to 95.2 %. The heavy fraction of rice husk bio-oil, primarily composed of lignin-derived phenolic compounds, could be upgraded to 98.3% hydrocarbons at 280 ℃ over RuCoW0.03/NC. The synergistic interaction between highly dispersed Co and Ru metal sites and WOx acidic sites is responsible for the excellent HDO activity of RuCoW0.03/NC. Besides, RuCoW0.03/NC exhibited high stability after four cycles.

Calcination temperature induced structural change of red mud and its enhanced catalytic performance for hydrocarbon-based biofuels production

Red mud (RM) is a strongly solid waste from alumina production, and the disposal of RM leads to series of environmental problems such as alkalization of occupied land and pollution of nearby water systems. Using RM as catalyst or carrier is one of the important methods for the comprehensive utilization of RM. Herein, the application of Ni supported RM (Ni/RM) for the efficient hydrodeoxygenation (HDO) of waste oils to produce hydrocarbon-based biofuels is reported. The structural properties of Ni/RM catalysts were investigated. The catalytic performance for HDO of palmitic acid as the model compound was evaluated. The results showed that RM calcinated at low temperature (400–600 °C) has a larger specific surface area and well dispersion of Ni, while the high calcination temperature (700 °C ~ 900 °C) results in sintering of metal oxides and lower dispersion of Ni. Ni/RM-500 shows the largest specific surface area of 77 m2/g. The conversion of palmitic acid over Ni/RM-500 is 100% at 250 °C, and alkanes are the only products at 300 °C. The reaction path of HDO and DCO/DCO2 is related to reaction temperature. The Ni/RM-500 shows the feasibility to different feedstocks. Finally, the catalytic performance of Ni/RM-500 was tested for 135 h, and the main reason causing the deactivation of Ni/RM-500 was revealed.

Synergy between Ru and WOx Enables Efficient Hydrodeoxygenation of Primary Amides to Amines

Synergy between Ru and WO<i>_x</i> Enables Efficient Hydrodeoxygenation of Primary Amides to Amines

Hydrodeoxygenation of guaiacol via in situ H2 generated through a water gas shift reaction over dispersed NiMoS catalysts from oil-soluble precursors: Tuning the selectivity towards cyclohexene

We report efficient hydrodeoxygenation of guaiacol via in situ hydrogen generated through Water Gas Shift (WGS) reaction over nanosized unsupported NiMoS catalysts with tunable selectivity toward cyclohexene. This strategy possesses a direct reaction route of oxygen-containing compounds from bio-oils depending on catalysts precursors and reaction conditions. The active catalytic species were formed in situ through the high-temperature decomposition of oil-soluble metal precursors followed by sulfidation in water-in-oil sulfur-containing emulsions. Unsupported NiMoS catalysts were found to provide 100% guaiacol conversion at 320–380 ℃ and 5 MPa CO pressure. Reaction routes and mechanisms for hydrodeoxygenation of guaiacol were proposed. Ni:Mo= 1:3 and sulfur content of 1.2–1.5 wt% favor higher cyclohexene selectivity decreases at low temperature and short reaction time (30–40 wt% water content, CO pressure of 5 MPa). The catalysts were found to be reusable at least 6 cycles in the sulfur-assisted hydrodeoxygenation of guaiacol with maintaining conversion, and active component evolution was studied.

Efficient hydrodeoxygenation of lignocellulose derivative oxygenates to aviation fuel range alkanes using Pd-Ru/hydroxyapatite catalysts

Bimetallic Pd-Ru/ hydroxyapatite (HAP) catalysts were developed together with Zirconium phosphate (ZrP) to prepare aviation fuel range hydrocarbons by one-pot HDO from lignocellulose-derived C15 oxygenate. The effects of the catalyst composition, reaction time, initial H2 pressure and reaction temperature on the HDO were explored. 84.24% C8-C15 alkanes could be obtained by Pd0.6-Ru1.8/HAP at 150 °C, 4 MPa H2. The HDO pathway and the stability of the catalyst were also investigated. To explore the synergy of bimetals and the efficiency of the catalysts, a series of characterizations were conducted. The results verified that the bimetallic catalyst had a better adsorption capacity for the substrate, and the ruthenium external electron density raised due to the introduction of palladium, thereby enhancing the hydrodeoxygenation activity of the catalyst.

Cobalt Supported on BN Catalyst with High B‐O Defects and Its Efficient Hydrodeoxygenation Performance of HMF to DMF**

AbstractIn this paper, a non‐noble catalyst was prepared by a simple homogeneous precipitation method and could be applied for 5‐hydroxymethylfurfural (HMF) hydrodeoxygenation (HDO) to 2, 5‐dimethylfuran (DMF). The catalyst was characterized by SEM, TEM, XRD, FT‐IR, BET, XPS, ICP and H2‐TPR. The cobalt species in the catalysts dispersed on the surface of boron nitride (BN) evenly. There is a strong interaction between BN and cobalt species in the Co/BN catalysts with vast B−O defects. Under the optimal conditions, HMF can be completely converted and the selectivity of Co/BN catalyst for DMF can reach as high as 91.67 %. It is crucial that the stability of the catalyst was maintained after five cycles by simple centrifugation. Due to its simple preparation process, low cost and high selectivity, the catalyst will be applied widely in the area of industrial catalysis.

Effect of promoter in hierarchical hollow Pt/Beta catalysts on the hydrodeoxygenation of phenol

An efficient hydrodeoxygenation (HDO) catalyst (i.e., Pt/Beta) is designed to improve the quality of bio-oil by removing chemicals with oxygen-containing functional groups (e.g., phenol). Hierarchical hollow Beta molecular sieves are obtained via an alkaline treatment with surfactants (i.e., dodecyl trimethyl ammonium bromides (DTAB) and stearyl trimethyl ammoium bromide (STAB)). Surfactants adsorb on the surface of zeolitic surface to inhibit alkaline etching and finally to form a hollow morphology. A competitive adsorption of phenol on acid and metallic sites is observed on Pt/Beta catalysts. A large amount of Brønsted acids with a higher acidic strength have a stronger adsorption ability of phenol. Therefore, more metallic sites are required to provide adsorption and HDO sites for phenol molecules. As for cyclohexane, more acids with a higher acidic strength are desired. However, coke covers acid sites and inhibits the dehydration reaction. These results provide a hierarchical hollow molecular sieves preparation method and propose the importance of acid regulation in the design of HDO catalysts.

Al-modified Pd@mSiO2 core-shell catalysts for the selective hydrodeoxygenation of fatty acid esters: Influence of catalyst structure and Al atoms incorporation

The development of robust catalysts for selective hydrodeoxygenation (HDO) of fatty acid esters is key for production of the diesel-range alkanes under mild conditions. Here, we report a stable and efficient HDO catalyst (Pd@Alx-mSiO2) that composed of inner uniformly dispersed metallic palladium core and the outer mesoporous silica shell doped with aluminum atoms. Using methyl palmitate as a model compound, Al-modified Pd@mSiO2 catalyst (Pd@Al3-mSiO2) exhibited higher catalytic performance (98% conversion rate and 99% selectivity towards diesel-range alkanes) as compared with the Pd@mSiO2 and conventional Pd/γ-Al2O3 catalysts (35% and 70% conversion rates, respectively) at 260 °C and 3.0 MPa H2. Further, when using vegetable oils such as soybean and palm oils as raw materials, high yields of diesel-range alkanes (> 80 wt%) can be obtained under the mild conditions. The HDO reaction pathway was more dominant than the decarbonylation pathway when the reaction was catalyzed by Pd@Al3-mSiO2 catalyst, thereby reducing the loss of carbon atoms. Detailed characterization (27Al NMR, NH3-TPD, and in situ Py-FTIR) suggests that the incorporation of aluminum atoms brings not only Lewis acid sites, but also Brønsted acid sites via the formation of SiOHAl bonds. The synergy between the metallic Pd, Lewis- and Brønsted-acid sites is responsible for its high HDO activity under the mild conditions. Additionally, the core-shell structure enables fatty aldehyde intermediate preferentially adsorbed on the aluminum atoms in the outer silica shell and avoids direct contacting with metallic Pd, which inhibits the cleavage of CC bonds to some extent. On the other hand, due to the protective effect of outer silica shell that inhibits the leaching and agglomeration of metallic Pd, the synthesized Pd@Al3-mSiO2 catalyst showed good stability with a slight loss (conversion decreased from 98% to 90%) over five cycles.

Efficient Hydrodeoxygenation of Bio-Oil Derived Phenols to C6+ Cycloalkanols/ Cycloalkanes Over Magnetic Carbon-Encapsulated Nickel Nanospheres

Efficient Hydrodeoxygenation of Bio-Oil Derived Phenols to C6+ Cycloalkanols/ Cycloalkanes Over Magnetic Carbon-Encapsulated Nickel Nanospheres

CoZn/N-Doped porous carbon derived from bimetallic zeolite imidazolate framework/g-C3N4 for efficient hydrodeoxygenation of vanillin

Non-noble Co–Zn/NPC fabricated by pyrolysis of Co–Zn-ZIF/g-C3N4 presents high efficiency in hydrodeoxygenation of the aldehyde group of vanillin under mild conditions.

Efficient Hydrodeoxygenation of Lignocellulose Derivative Oxygenates to Aviation Fuel Range Alkanes Using Pd-Ru/Hydroxyapatite Catalysts

Efficient Hydrodeoxygenation of Lignocellulose Derivative Oxygenates to Aviation Fuel Range Alkanes Using Pd-Ru/Hydroxyapatite Catalysts

Promotion of sulfonic acid groups on biomass carbons loading ultrafine palladium nanoparticles for the efficient hydrodeoxygenation of vanillin in water

Carbonaceous catalysts with sulfonic acid (-SO3H) groups are showing promising performances in the conversion of mono- and poly-saccharides, however, their applications in the hydrodeoxygenation (HDO) of oxygen-rich lignin derivatives are rarely reported. Herein, we report a facile synthetic approach for one-step preparation of porous carbonaceous solid acids with –SO3H groups (OHCA) where monosaccharide, polysaccharide, and raw biomass can be used as carbon precursors. These porous carbonaceous solid acids supported ultrafine palladium nanoparticles (Pd/OHCA) exhibited excellent performances in the HDO of vanillin (VAN) in water. We found that Pd nanoparticles (Pd NPs) were responsible for the hydrogenation of VAN to vanillyl alcohol (VAL) and acidic groups were crucial for the hydrogenolysis of generated VAL to 2-methoxy-4-methylphenol (MMP). Importantly, VAL once generated can be immediately converted to MMP via synergistic catalysis between acidic groups and Pd NPs, avoiding the formation of by-products. Pd/OHCA catalyst also exhibited excellent stability in the HDO of VAN and retained its activities in the six consecutive runs. The findings of this work provide a new thought for the HDO of biomass derivatives over biomass-based carbon catalysts.

Selective upgrading of biomass-derived benzylic ketones by (formic acid)–Pd/HPC–NH2 system with high efficiency under ambient conditions

Selective upgrading of biomass-derived benzylic ketones by (formic acid)–Pd/HPC–NH2 system with high efficiency under ambient conditions

Bimetallic Ni‐Re catalysts for the efficient hydrodeoxygenation of biomass‐derived phenols

The development of non–noble metal–based catalysts for the hydrodeoxygenation (HDO) upgrading of biomass pyrolysis oils is crucial for realizing the cost-effective biofuel production. In this paper, we report on the enhanced HDO activity of the rhenium-promoted nickel catalysts (Ni-Re) for the HDO of a pyrolysis oil model compound, guaiacol. The catalyst screening studies revealed that the Ni-Re displayed a considerably higher HDO activity than other monometallic (Ni, Re, Cu, Co) and bimetallic catalysts (Cu-Re, Co-Re), highlighting its unique catalytic property. In order to optimize the catalytic activity and reveal the structure–activity relationship of the Ni-Re catalysts, the effects of the Ni/Re ratio and type of support (SiO2, TiO2, and ZrO2) on the catalyst structure and HDO activity were investigated in detail. The results showed that the addition of rhenium to nickel altered both geometric and electronic structures of nickel significantly. The Ni-Re/SiO2 catalyst with a Ni/Re ratio of 0.315 achieved ~95% yield of the desired deoxygenation product, cyclohexane, at 523 K and 30 bar-H2 after 5 hours. Novelty Statement The upgrading of biomass pyrolysis oils to hydrocarbon fuels oftentimes requires the use of noble metal catalysts and harsh reaction conditions (e.g., high H2 pressure), all of which greatly increase the process cost. In this work, a highly active and nonprecious metal–based catalyst, bimetallic Ni-Re/SiO2, is developed for the cost-effective upgrading of biomass-derived phenols to deoxygenated hydrocarbon fuels at low temperature and low pressure.

Enhancing Hydrodeoxygenation of Bio-oil via Bimetallic Ni-V Catalysts Modified by Cross-Surface Migrated-Carbon from Biochar.

Aromatics from selective hydrodeoxygenation (HDO) of biomass-derived bio-oil are an ideal feedstock for replacing industrial fossil products. In this study, biochar-modified Hβ/Ni-V catalysts were prepared and tested in the atmospheric HDO of guaiacol and bio-oil to produce aromatics. Compared with unmodified Hβ/Ni-V, higher HDO activity was achieved in catalysts with all kinds of biochar modifications. Especially, the pine nut shell biochar (PB)-modified PB-Hβ-8/Ni-V showed the highest selectivity to aromatics (69.17%), mainly including benzene and toluene. Besides, under the conditions of 380 °C and weight hourly space velocity (WHSV) of 0.5 h-1, the cleavage of CAr-OH (CAr means the carbon in the benzene ring) was promoted to form more aromatics. Moreover, great recyclability (58.77% aromatics for the reactivated run-3 test) and efficient HDO of bio-oil (44.9% aromatic yield) were also achieved. Based on the characterization results, the enhanced aromatic selectivity of PB-Hβ-8/Ni-V was attributed to the synergetic effect between PB and Hβ/Ni-V. In detail, a stable surface migrated-carbon layer was formed on Hβ/Ni-V via the metal catalytic chemical vapor deposition (CVD) process of the pyrolysis PB volatiles. Simultaneously, a carbothermal reduction driven by the migrated-carbon took place to decorate the surface metals, obtaining more Ni0 and V3+ active sites. With this synergism, increased Ni0 sites promoted H2 adsorption and dissociation, which improved the hydrogenation activity. Furthermore, the higher affinity of the reactant and increased oxygen vacancies both contributed to enhancing the selective surface adsorption of oxygenous groups and the cleavage of the CAr-OH bond, thus improving the deoxygenation activity. Therefore, the HDO activity was improved to form more target aromatics over biochar-modified catalysts. This work highlighted a potential avenue to develop economic and environmental catalysts for the upgrading of bio-oil.

Highly efficient hydrodeoxygenation of lignin-derivatives over Ni-based catalyst

Designing highly active non-noble metal catalysts for the hydrodeoxygenation of renewable biomass into value added biofuels and chemicals is highly desirable, but still remains a challenging task. In this work, flower-like Ni catalysts supported on mixed metal oxides (MMO) were fabricated by calcination and reduction of NiZnAl layered double hydroxide (LDH) precursors. The optimized Ni0.5Zn1.5Al1-MMO catalyst displayed excellent hydrodeoxygenation catalytic activity for lignin derivatives at 130 °C, being much superior with the catalysts prepared by impregnation and coprecipitation method, as well as most of the reported non-noble catalysts. The superior activity originated from the synergetic effect of large specific surface area of the support, strong metal-support interaction and more acid sites. This research provides a feasible route for the constructing efficient hydrodeoxygenation catalysts by tuning the physicochemical property and composition of the catalyst.

Ordered macroporous Co3O4-supported Ru nanoparticles: A robust catalyst for efficient hydrodeoxygenation of anisole

A three-dimensional ordered macroporous Co3O4 (OM-Co3O4) supported Ru catalyst was developed for the efficient hydrodeoxygenation (HDO) of anisole. It is revealed that small-sized Ru nanoparticles evenly distributed over the surface of OM-Co3O4 with large quantities of oxygen vacancies could strongly capture Ru0 species, thereby resulting in strong Ru-Co3O4 interactions. Compared with commercial Co3O4 supported Ru catalyst, Ru/OM-Co3O4 displays a better catalytic HDO performance, with a high cyclohexane yield of 92.4% at 250 °C and 0.5 MPa hydrogen pressure after 5 h on stream. Such a significant efficiency of Ru/OM-Co3O4 is mainly attributed to both high dispersion of Ru0 species and an enhanced formation of surface defects, as well as the unique macroporous framework of OM-Co3O4 support.

Efficient hydrodeoxygenation of phenolic compounds and raw lignin-oil under a temperature-controlled phase-transfer catalysis

An effective binary catalyst by using tungstic acid (H2WO4) and Ru/C was employed for the hydrodeoxygenation (HDO) of phenolic compounds and raw lignin-oil. H2WO4 was presented as solid at ambient temperature, but it dissolved at high temperature above 100 °C and therefore functioned as an active homogeneous catalyst. This phenomenon resulted in a temperature-controlled phase-transfer behavior in the HDO of phenolic compounds. An efficient HDO performance and an exceptional reusability for guaiacol HDO were presented by this bifunctional catalyst, which can be reused more than 10 times with guaiacol conversion and cyclohexane selectivity over 90%. The comparison of traditional liquid organic and mineral acids, as well as solid acids, with H2WO4 confirmed the outstanding catalytic performance of H2WO4 and highlighted the advantages of H2WO4 as a homogeneous catalyst. Besides guaiacol, other phenolic compounds including various monomers and dimers all exhibited good HDO results, with 100% conversion and cycloalkanes selectivity. Moreover, the raw lignin-oil can be efficiently deoxygenated under the catalysis of this bifunctional catalyst. 99.3% content of hydrocarbons was obtained in the upgraded lignin-oil, which was promising to be used as fuel directly. This catalytic system has great potential for the industrial application of lignin-oil upgrade.

Promotion of Sulfonic Acid Groups on Biomass Carbons Loading Ultrafine Palladium Nanoparticles for the Efficient Hydrodeoxygenation of Vanillin in Water

Promotion of Sulfonic Acid Groups on Biomass Carbons Loading Ultrafine Palladium Nanoparticles for the Efficient Hydrodeoxygenation of Vanillin in Water