Hydrodeoxygenation Activity Research Articles

Cs-promoted hydrogenation upgrading of bio-oil over macroporous Ru-containing catalysts using model compounds

Hydrogenation upgrading is an effective technique that lowers the oxygen content of bio-oil with the aim of improving its quality. In order to fabricate a series of Ru-based catalysts for the hydrodeoxygenation of bio-oil, several all-silica supports with different pore sizes are synthesized and modified with Al and Cs in this work. The physical morphology and electronic structure of the catalysts are characterized using multiple techniques including X-ray diffraction, in-situ pyridine adsorption infrared spectroscopy, in-situ diffuse reflectance Fourier transform infrared spectroscopy, Raman spectroscopy, CO2 temperature-programmed desorption, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and N2 physical adsorption-desorption testing. Phenol, guaiacol, anisole and o-cresol are selected as model compounds to investigate the hydrodeoxygenation reactivity of the catalysts. The results reveal that there is a strong linear correlation between the pore size of the catalysts and the rates of the hydrogenation and hydrodeoxygenation of phenol. Importantly, both the oxygen vacancy density and relative content of Brønsted and Lewis sites (B/L) of the catalysts can be greatly increased by Cs modification, which further linearly promotes the hydrodeoxygenation activity of the catalysts. In addition, the in-situ infrared spectroscopy results show that the catalysts modified by Al and Cs heterolytically cleave H2 to supply H+ for the reaction. This work presents a novel approach for fabricating catalysts employed in the hydrotreatment process of bio-oil.

Potential of (La-)NiCu catalysts for the hydrodeoxygenation of 4-(2-furanyl)-3-buten-2-one into fuels: Investigation of support and La addition

Aiming at the valorization of furfural-derived compounds, the potential of (La-)NiCu catalysts for the hydrodeoxygenation of 4-(2-furanyl)-3-buten-2-one has been assessed. The impact of support acidity and the effects of modifying the support with La have been explored. While catalysts with non-acidic supports solely lead to hydrogenation, the acid sites enable furanic ring opening. Additionally, changing the support alters the metal-support interaction strength, with stronger interactions reducing the NiCu alloy particle size and increasing activity. Furthermore, according to Density of States calculations, La further enhances the hydrodeoxygenation activity by increasing the adsorption strength. Also, for the acidic supports, it increases the relative abundance of NiCu alloy on the support surface, further increasing the specific activity. The La-NiCu-Al catalyst demonstrated was the best performing catalyst at 200 °C and 40 bar H2, achieving a high conversion rate of 77 mol kgcat−1 h−1 with a combined selectivity of 29 % towards octane and BTHF at 99 % conversion, and stability over 5 hours Time-On-Stream. Additionally, isopropyl alcohol proved to be an excellent hydrogen donor, as the external H2 pressure does not substantially impact the catalyst activity and selectivity, but H2 itself proved to be important for the catalyst stability.

Carboxyl-Decorated UiO-66 Supporting Pd Nanoparticles for Efficient Room-Temperature Hydrodeoxygenation of Lignin Derivatives.

Hydrodeoxygenation (HDO) of lignin derivatives at room-temperature (RT) is still of challenge due to the lack of satisfactory activity reported in previous literature. Here, it is successfully designed a Pd/UiO-66-(COOH)2 catalyst by using UiO-66-(COOH)2 as the support with uncoordinated carboxyl groups. This catalyst, featuring a moderate Pd loading, exhibited exceptional activity in RT HDO of vanillin (VAN, a typical model lignin derivative) to 2-methoxyl-4-methylpheonol (MMP), and >99% VAN conversion with >99% MMP yield is achieved, which is the first metal-organic framework (MOF)-based catalyst realizing the goal of RT HDO of lignin derivatives, surpassing previous reports in the literature. Detailed investigations reveal a linear relationship between the amount of uncoordinated carboxyl group and MMP yield. These uncoordinated carboxyl groups accelerate the conversion of intermediate such as vanillyl alcohol (VAL), ultimately leading to a higher yield of MMP over Pd/UiO-66-(COOH)2 catalyst. Furthermore, Pd/UiO-66-(COOH)2 catalyst also exhibits exceptional reusability and excellent substrate generality, highlighting its promising potential for further biomass utilization.

Regulating the Hydrodeoxygenation Activity of Molybdenum Carbide with Different Diamines as Carbon Sources

The hydrodeoxygenation (HDO) of renewable fats or fatty acids into alkanes is a powerful measure to address energy and environmental crises. Molybdenum carbide-based catalysts are promising due to their platinum-like noble metal electronic properties. In this paper, Mo2C catalysts were prepared by one-step carbonization of amine molybdenum oxide (AMO) precursors using diamines with different carbon chain lengths as ligands. The physical and chemical properties and the HDO catalytic activity of the catalysts were investigated. The results indicate that as the carbon chain of diamines in the precursor increases, the carbon content of the catalysts in the surface and bulk phase increases. The Mo2C-12 catalyst exhibited excellent catalytic performance, with a palmitic acid conversion rate of 100% and an alkane selectivity of 96.6%, which are attributed to the smallest particle size, largest pore size, and synergistic effect of carbon. This work provides a simple and safe method for regulating the surface properties of Mo2C catalysts.

Design of a highly active TiO2-supported Ni2P@C catalyst with special flower-like radial channels for quick p-cresol hydrodeoxygenation

Efficient hydrodeoxygenation (HDO) catalysts are of great important for converting biomass to value-added chemicals and fuels. Herein, a novel strategy was proposed for preparing a highly dispersed carbon-encapsulated flower-like radial channels TiO2-supported catalysts (Ni2P@C/FLRC-TiO2). The effect of P and pore structure of the TiO2 support on the p-cresol HDO performance was investigated. An appropriate P content improves the HDO performance by increasing the acidity, while the open radial channels of Ni2P@C/FLRC-TiO2 greatly reduces the reaction time and enhance the HDO activity by promoting rapid mass transfer and accessibility of active sites. The highly dispersed carbon-encapsulated Ni2P@C nanoparticles further improve the HDO activity and stability. Among the prepared catalysts, Ni2P@C/FLRC-TiO2-1 (initial NaH2PO2:Ni-MOF/FLRC-TiO2 mass ratio = 1) exhibited the best HDO performance, yielding 100 % of the p-cresol deoxygenation products within 1.5 h under mild conditions. The excellent HDO performance originates from the synergy between FLRC-TiO2 radial channels and the Ni2P@C nanoparticles.

Catalytic bio-oil upgrading using Fe-Co/Al2O3 and co-processing with vacuum gas oil

The current study explores the hydrodeoxygenation (HDO) of pine sawdust derived pyrolysis bio-oil and co-processing of raw bio-oil with Vacuum Gas Oil (VGO) in a micro-activity testing (MAT) unit. The catalytic performance of mono- and bi-metallic catalysts were tested for bio-oil upgrading. Notably, FeCo (2:1)/Al2O3 catalysts exhibited superior HDO activity compared to their mono-metallic counterparts. Co-processing of raw bio-oil (2–10 wt%) with VGO led to a notable increase in gasoline yield of ∼48% with a 6 wt% blend. Maximum conversion was achieved with 8 wt% blend, further increasing the proportion, conversion decreased significantly affecting the product distribution.

Sustainable biofuel synthesis from non-edible oils: a mesoporous ZSM-5/Ni/Pt catalyst approach.

This work examines the hydrodeoxygenation (HDO) activity of non-edible oils using a high surface area catalyst. The HDO activity was thoroughly examined and contrasted using the high surface area catalyst Ni/Pt-ZSM-5 as well as other supports like MCM-48 and H-beta. Ni/Pt bimetals supported on mesoporous ZSM-5 were created via reverse order impregnation to facilitate HDO of non-edible oils. Techniques such as XRD, FT-IR, BET, HR-TEM, HR-SEM, TPD, and TGA were used to characterize the produced catalysts. The synthesized catalysts considerably influenced the hydrodeoxygenation activities for the synthesis of lengthy chain hydrocarbons in a stainless-steel reactor with a high-pressure fixed bed between 300 and 375 °C under 10-40 bar hydrogen pressure. High levels of Ni/Pt-ZSM-5 acidity, textural, and H2 consumption qualities were discovered. Distributions of the products were also reviewed, along with comparisons of the structure-activity connections.

Fabrication modulation of lignin-derived carbon nanosphere supported Pd nanoparticle via lignin fractionation for improved catalytic performance in vanillin hydrodeoxygenation

Nano-lignin presents great potential in advanced carbon materials preparation since it integrates the advantages of nanomaterials as well the preferable properties of lignin (e.g. high carbon content and highly aromatic structure). Herein, lignin-derived carbon nanosphere supported Pd catalysts (Pd@LCNS) were prepared via a two-step carbonization of Pd2+ adsorbed lignin nanospheres (LNS) and applied in vanillin hydrodeoxygenation. The effect lignin heterogeneity on the synthesis of Pd@LCNS as well as its catalytic performance was further investigated through the synthesis of Pd@LCNS using three lignin fractions with different molecular weight. The results showed that the three Pd@LCNSs exhibited significant differences in the morphology of both carbon support and Pd nanoparticles. Pd@LCNS-3 prepared from high molecular weight lignin fraction (L-3) presented stable carbon nanosphere support with the smallest particle size (∼150 nm) and the highest Pd loading amount (3.78 %) with the smallest Pd NPs size (∼1.6 nm). Therefore, Pd@LCNS-3 displayed superior catalytic activity for vanillin hydrodeoxygenation (99.34 % of vanillin conversion and 99.47 % of 2-methoxy-4-methylphenol selectivity) at 90 °C without H2. Consequently, this work provides a sustainable strategy to prepare uniformly dispersed lignin-based carbon-supported Pd catalyst using high molecular weight lignin as the feedstock and further demonstrate its superior applicability in the selective transfer hydrogenation of vanillin.

One-pot solvent-free sequential synthesis of high-density polycycloalkanes fuels from lignin-derivatives over laminated NbOPO4 catalyst

Upgrading lignocellulose biomass to renewable fuels is essential to achieve carbon neutrality. However, the multiple synthetic, and purification steps as well as the employment of solvents in the production of renewable fuel inhibit the overall yields and cause the waste of energy and resources. Herein, a new catalytic strategy for one-pot solvent-free sequential synthesis (OSS) of perhydrofluorene and dicyclohexylmethane was developed from lignin-derivatives. A two-dimensional layered nanosheet niobium phosphate (NbOPO4-IB) catalyst was fabricated to efficiently integrate the alkylation of phenol and benzyl alcohol and sequential hydrodeoxygenation with a cocatalyst of Ru/C. The high crystalline NbOPO4 phase and the lamellar morphology contributes to the large specific surface area to expose more active sites, especially more Brønsted acid sites. The NbOPO4-IB catalyst with a suitable Brønsted/Lewis acid ratio of 1.49 favors the selectivity of fuel precursors benzyl phenol in the alkylation and also provides the appropriate acid strength to promote hydrodeoxygenation activity. NbOPO4-IB also shows good reusability. Excessive phenol plays a vital role in promoting the alkylation reaction by dissolving the intermediates, and then into cyclohexane to enhance the H2 dissolution in the hydrodeoxygenation. A possible mechanism of OSS from lignin-derivatives into polycycloalkanes over the cocatalysts was proposed.

Boosting the Hydrodeoxygenation Activity and Selectivity of Ni/(M)-SBA-15 Catalysts by Chemical Alteration of the Support.

The influence of the acid sites in the hydrodeoxygenation of anisole performed over Ni catalysts supported on SBA-15 modified with metal oxides (Ni/M-SBA-15, M = Ti, Zr, Al, or Nb) was demonstrated. Catalysts were characterized by SEM-EDX, nitrogen physisorption, XRD, UV-visible DRS, TPR, TPD of ammonia, IR-Py, O2 chemisorption, and high-resolution transmission electron microscopy. The mesoporous structure and the hexagonal arrangement of the supports were maintained in the catalysts. Ni catalysts supported on modified M-SBA-15 exhibited a higher metal-support interaction, an increase in the acidity and, as a consequence, improved selectivity to cyclohexane. The deoxygenation reaction rate constants increased as Ni/SBA-15 < Ni/Ti-SBA-15 < Ni/Nb-SBA-15 < Ni/Zr-SBA-15 < Ni/Al-SBA-15, which is attributed to the increase in the amount and strength of acid sites, especially of the Brønsted ones, which promotes the cleavage of the C-O bond. It is also important to keep the metal/acid sites together to obtain high activity and selectivity to hydrodeoxygenated products.

Solvent assisted to prepare shell structured Cu/γ-Al2O3 catalyst with low Cu content for oil efficient hydrodeoxygenation to high-quality biofuel

Using biomass “green carbon” can effectively alleviate the energy crisis and environmental protection problems. To achieve efficient removal of oxygen atoms, retain complete carbon chain structures, and maximize the economy of carbon atoms for the inedible or waste bio-oils, a novel and unique shell-style Cu/γ-Al2O3 catalyst with low Cu content was developed to solve the current problems including easy sintering and poor hydrodeoxygenation (HDO) activity of the studied catalysts. The shell Cu/γ-Al2O3 catalyst (Cu-CPA) with the Cu content of 3 wt% prepared by acetone as solvent has excellent cycle-stable HDO performances, the methyl laurate hydrogen conversion and C12 alkanes selectivity were 87.2 and 80.0 % at 400 °C, respectively, which were equivalent to the activities of the ordinary 10 wt% Cu/γ-Al2O3 catalyst prepared by wet impregnation using water as a solvent. The polarity of the impregnating solution modulates the shell layer thickness of the Cu-based catalysts to improve the surface chemical composition and pore structure of the catalysts, which in turn affects the lipids HDO performances of the corresponding catalyst. Active heterogeneous shell Cu-CPA catalyst showed high activity, selectivity, and stability in HDO, which can be attributed to the unique structure with suitable active shell thickness and high utilization rate of the metal Cu active components. This study provides feasible ideas for the preparation of shell-type catalysts, the design of anti-sintering Cu-based catalysts, and the production of renewable biofuels.

Efficient solvent-free hydrodeoxygenation of bio-lipids over bifunctional NiW catalyst: Manipulations of surface-active sites by thermal pretreatment

The effect of thermal pretreatment on the bifunctional NiW catalyst and its hydrodeoxygenation (HDO) performance on oleic acid were investigated. Increasing the calcination temperature (CT) not only led to the growth of NiW particles, but caused the migration of Ni to the surface that resulted in the segregation of W. The reduction temperature (RT) was also able to tune the catalyst surface composition. A lower RT (600 °C) led to a W-rich surface, while a higher one (700 °C) interestingly resulted in a Ni-rich surface. To this end, the ratio of surface-active sites, i.e., the partially reduced W species (Wδ+) to Ni0 ones (Wδ+/Ni0), was manipulated. The highest Wδ+/Ni0 ratio of 2.6 was reached at the CT and RT of 550 °C and 700 °C, respectively, which contributed to an impressively high solvent-free deoxygenation of 95.1% at only 300 °C. The deoxygenation rate (rdeoxy.) was much higher than that of the reported non-precious catalysts, even comparable to the precious ones. Additionally, a high catalyst durability was found on non-acid feedstocks like triglycerides, long-chain alcohols, etc., but an acidic substrate like oleic acid tended to leach the loaded metals that eventually lessened the HDO activity.

In situ topologically prepared Co–Zn-based mixed metal oxide bimetallic catalysts for guaiacol hydrodeoxygenation

Bio-oil, derived from biomass pyrolysis, can be used as an alternative to fossil fuels after treatment through hydrodeoxygenation (HDO) reactions. In this study, a series of Co–Zn-based mixed metal oxide (Co-Zn-MMO) catalysts were synthesized using Co–Zn-based layered double hydroxide (Co-Zn-LDH) as a precursor. The catalysts were then used in the HDO reaction of guaiacol and larch wood-derived bio-oil. The Co–Zn-MMO catalysts were characterized via scanning electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller analysis, X-ray photoelectron spectroscopy, hydrogen-based temperature-programmed reduction, and ammonia temperature-programmed desorption techniques. Among the Co-Zn-MMO catalysts, the Co1-Zn2-MMO catalyst, with a Co-to-Zn molar ratio of 1:2, exhibited the highest acidity, the largest pore size and pore capacity, and the highest density (65.56%) of Co2+δ-Ov-Zn2-δ oxygen vacancy. These characteristics resulted from the metal–support interaction effect, leading to superior HDO activity for guaiacol. Furthermore, the Co1-Zn2-MMO catalyst effectively removed heteroatomic components from larch wood-derived bio-oil, thereby enhancing the quality of the bio-oil product.

Linear Scaling Relationships for Furan Hydrodeoxygenation over Transition Metal and Bimetallic Surfaces.

Brønsted-Evans-Polanyi (BEP) and transition-state-scaling (TSS) relationships have become valuable tools for the rational design of catalysts for complex reactions like hydrodeoxygenation (HDO) of bio-oil (containing heterocyclic and homocyclic molecules). In this work, BEP and TSS relationships are developed for all the elementary steps of furan activation (C and O hydrogenation and CHx -OHy scission, for both ring and open-ring intermediates) to oxygenates, ring-saturated compounds and deoxygenated products on the most stable facets of Ni, Co, Rh, Ru, Pt, Pd, Fe and Ir surfaces using Density Functional Theory (DFT) calculations. Furan ring opening barriers were found to be facile and strongly dependent on carbon and oxygen binding strength on the investigated surfaces. Our calculations suggest linear chain oxygenates form on Ir, Pt, Pd and Rh surfaces due to their low hydrogenation and high CHx -OHy scission barriers, while deoxygenated linear products are favoured on Fe and Ni surfaces due to their low CHx -OHy scission and moderate hydrogenation barriers. Bimetallic alloy catalysts were also screened for their potential HDO activity and PtFe catalysts were found to significantly lower the ring opening and deoxygenation barriers relative to the corresponding pure metals. The developed BEPs for monometallic surfaces can be extended to estimate the barriers on bimetallic surfaces for ring opening and ring hydrogenation reactions but fails to predict the barriers for open-ring activation reactions due to the change in transition state binding sites on the bimetallic surface. The obtained BEP and TSS relationships can be used to develop microkinetic models for facilitating accelerated catalyst discovery for HDO.

Unveiling the in-situ formation of single-atomically dispersed Pd-Fe bimetallic catalytic sites during anisole hydrodeoxygenation

Hydrodeoxygenation (HDO) is a promising route to convert biomass molecules into biofuels, which is usually promoted by supported noble metal catalysts. It is still one of the key issues to reduce the usage of noble metal for improving the atomic efficiency of the catalyst. As a type of emerging catalytic materials, single-atomically dispersed bimetallic catalyst (SDBM) is a promising candidate for this purpose. Herein, we investigated a single-atomically dispersed Pd/Fe2O3 catalyst with the exceptional HDO activity. At 573 K, anisole conversion is 99% while the selectivity to HDO products is 84%. The turnover rate per Pd atom is 182.2 h−1, which is remarkably greater than that of supported Pd nanoparticles. Additionally, it exhibits good stability for more than 110 h of continuously operation. The authentic catalytic sites during reaction was studied by comprehensive techniques. The presence of the Pd atoms on Fe2O3 changes the surface chemistries of the catalyst surface, then boosts the HDO activity consequently. As unveiled by in-situ X-ray absorption spectroscopy, the Pd atoms are coordinated with 2.76 nearby Fe atoms in average via metallic Pd-Fe bonds. Under HDO reaction conditions, single atomically dispersed Pd1Fe3 bimetallic sites are generated in-situ and act as the authentic catalytic sites.

Ni/HZSM-5 catalysts for hydrodeoxygenation of polycarbonate plastic wastes into cycloalkanes for sustainable aviation fuels

Hydrodeoxygenation (HDO) is one of the effective methods for upcycling polycarbonate (PC) plastic waste, but the development of low-cost, high-performance HDO catalysts still faces great challenges. In this work, we report that a bifunctional Ni/HZSM-5 catalyst can directly upgrade PC plastic wastes into sustainable aviation fuel ranged cycloalkanes in high yields (99.3 %) with 81.2 % yield of C15 dicycloalkane under mild reaction conditions (190 °C, 4 MPa H2). Controlled reactions of PC and probe molecules demonstrated the conversion of PC into C15 dicycloalkanes involves PC depolymerization by direct cleavage of C-O bonds adjacent to benzene ring and ester group, forming C15 aromatics and C15 monophenols at the metal sites, followed by hydrogenation of C15 aromatics rings on metallic Ni sites and HDO of C15 monophenols on metal-acid dual sites parallel to generate C15 dicycloalkane. The C-C cracking mainly occurred on the tertiary carbon adjacent to the benzene ring on acidic sites of HZSM-5, thus forming C6∼C9 monocyclic alkanes. The realization of this process can be attributed to the cooperation between metal sites and acid centers on Ni/HZSM-5. Besides, the metal-acid balance (MAB) in Ni/HZSM-5 significantly affected the HDO activity and product distribution. 20Ni/HZSM-5(200) with suitable MAB showed good HDO activity and excellent selectivity to C15 dicycloalkane. In addition, the obtained catalyst was also capable of converting common real PC plastics wastes (CD disk, DVD disk and PC sheet) into cycloalkanes with the yield up to 98 % and exhibited excellent stability. This approach to construct inexpensive bifunctional catalysts highlights an efficient and reliable route for HDO of PC to sustainable aviation fuel, providing a new avenue towards a circular economy.

Mesoporous Ni/Al-MCM-41 catalysts for highly active and selective hydrodeoxygenation of anisole to cyclohexane

Ni/Al-MCM-41(x) catalysts were synthesized and tested in the hydrodeoxygenation of anisole as a model compound of bio-oil. Prepared catalysts behave as bifunctional metal-acid catalysts combining the metal function of the reduced Ni nanoparticles with the acid function of the Al-MCM-41 supports. Nickel loading in the catalysts was maintained constant (5 wt%), while Al content in the supports was varied (Si/Al molar ratios x = 120, 90, 60 and 30). The Ni/Al-MCM-41(x) catalysts showed significantly higher hydrodeoxygenation activities than the reference Ni/Al2O3 and the Ni/MCM-41 catalyst without Al. In addition, they showed high selectivity towards the formation of the deoxygenated products, with more than 96% selectivity to cyclohexane. The best activity and selectivity results were obtained with the Ni/Al-MCM-41(90) catalyst. This result was attributed to an optimum balance of metal and acid sites, both of which participate in different steps of anisole hydrodeoxygenation and generate a synergistic effect.

Optimization of catalyst activity and stability in the m-cresol hydrodeoxygenation through Ni particle size control

By taking advantage of different nanoparticle size control methodologies, the precise role of Ni particle size (from 1 nm to 9 nm) was evaluated in the HDO of m-cresol in vapor phase at 573 K under atmospheric pressure. The m-cresol HDO reaction pathways were found to be Ni-particle size dependent. The direct deoxygenation (DDO) rate increased by 10 times when decreasing Ni particle size from 9 nm to 1 nm, while the hydrogenation (HYD) and hydrogenolysis (HYG) rates moderately increased. By applying a geometric model, reaction rates were correlated to the different type of sites. Edges and corner sites (smaller particles) favor aromatics production (DDO route), while face sites (larger particles) favor both HYD and HYG routes. Catalysts partially deactivated due to coke formation, with only slight sintering observed for 1 nm Ni particles. Such findings may serve in the further preparation of active and selective catalysts for bio-oils upgrading into fuel.

Selective Hydrodeoxygenation of Guaiacol to Cyclohexane over Ru-Catalysts Based on MFI Nanosheets

Bio-oils derived from the pyrolysis of lignin-based biomass often contain a variety of oxygenated compounds, which can compromise their usefulness as a fuel. To improve the quality of bio-oil, catalytic hydrodeoxygenation (HDO) is a crucial step that removes oxygen from the oil in the form of water. In this study, we showed that MFI nanosheets are excellent supports for Ru-catalysts. We synthesized highly crystalline MFI nanosheets using a simple hydrothermal seeding procedure; the final material was obtained in 56 h of crystallization. We investigated the activity of Ru supported on different materials. Our findings indicated that Ru supported on hierarchical MFI demonstrated excellent activity in HDO of guaiacol. Our results demonstrated that Ru/ZNS-56 achieved nearly 100% selectivity towards cyclohexane under mild conditions (200 °C, 50 bar H2, 1 h).

Conversion of lignin to high yields of aromatics over Ru–ZnO/SBA-15 bifunctional catalysts

The development of a highly active and robust catalyst for the conversion of lignin, the largest volume of renewable aromatic resource in nature, to value-added aromatics is of great importance in sustainable chemistry. However, the condensation of lignin depolymerization intermediates into recalcitrant macromolecules restricts high yields of desired products, and this remains a great challenge in lignin valorization. Here, a serious of bifunctional Ru–ZnO/SBA-15 catalysts were synthesized for lignin conversion to aromatics. Roles of Ru and ZnO in these catalysts for lignin conversion were in-depth analyzed. The effect of the ratio of Ru to ZnO was studied. Other reaction conditions including temperature and time were systematically optimized. More than 51.3% yields of aromatics were obtained over Ru–10ZnO/SBA-15 at 240 °C for 4 h. Structure-activity relationship research of the catalyst revealed that the high yield of product could be attributed to the following three reasons: 1) the Lewis acidic sites on Ru/SBA-15 are significantly improved after ZnO modification, and thus promotes the C–O bond cleavage; 2) the oxophilic ZnO is beneficial to absorb the substrate and reaction intermediates, and therefore enhances the hydrodeoxygenation activity of the adjacent Ru; 3). The interaction between Zn and Ru in Ru–ZnO/SBA-15 changes Ru electronic properties and leads to the formation of highly active catalytic sites with high electron density. These results indicated that the bifunctional Ru–ZnO/SBA-15 catalyst with high catalytic activity could be a good choice for lignin conversion to high-yield aromatics.