H2 Pressure Research Articles

Zwitterionic Halido Cyclopentadienone Iron Complexes and Their Catalytic Performance in Hydrogenation Reactions.

The zwitterionic halido cyclopentadienone iron complexes FeX(CO)2-NMe3 (X = Cl, Br, I) were prepared and characterized by NMR, XRD, MS, IR, and elemental analysis. Their catalytic performance in hydrogenation and transfer hydrogenation was assessed. Transfer hydrogenation in boiling iPrOH with acetophenone as the test substrate showed no conversion with FeI(CO)2-NMe3. Hydrogenation reactions under H2 pressure (7.5 bar) in water as solvent showed up to 93% conversion with FeI(CO)2-NMe3 (2.5 mol %) using acetophenone as the test substrate. The overall relative reactivity order was established to be Cl < Br < I, reflecting the relative bond strengths of the Fe-X bonds. Although the compounds presented in this study can be used as precatalysts for hydrogenation reactions in water, the need to employ high temperatures, leading to more catalyst decomposition, as evidenced by pressurized sample infusion-electrospray ionization-mass spectrometry (PSI-ESI-MS), and high catalyst loading limits their usefulness as catalysts. The limit can be circumvented in part by salt effects analogous to those in classical solvolysis chemistry.

Highly efficient metal-acid synergetic catalytic fractionation of lignocellulose under mild conditions over lignin-coordinated N-anchoring Co single-atom catalyst

Lignin reductive depolymerization via a lignin-first strategy is extremely attractive but practically challenging due to the harsh reaction conditions, such as high temperature and high external H2 pressure. Herein, we demonstrate a highly efficient acid-assisted reductive fractionation of lignocellulose over a cobalt monatomic catalyst (Co SAs-N@LC) under mild temperature without H2. The Co SAs-N@LC with a Co-N4 conformation was fabricated by pyrolyzing phenolic-OH rich lignin-metal complex mixed with melamine. When subjected to poplar reductive fractionation at 160 °C with 0.1% H2SO4, the Co SAs-N@LC achieved a high monophenol yield of 41.7% with near complete delignification (99.7%), which was credited to the acid-metal synergy on effective lignin depolymerization, more importantly on condensation inhibition. Furthermore, thanks to the acid-catalyzed hydrolysis, xylan was simultaneously liberated, leaving a cellulose-rich fraction as the solid fraction. DFT calculations revealed that the Co-N4 conformation endowed the catalyst superior hydrogen evolution capacity and the monatomic catalyst showed satisfactory recycling stability due to the acid-resistant N-anchoring and the minimized catalyst fouling. Therefore, this work provides an effective approach for reductive fractionation of lignocellulose under mild conditions, more importantly a total biomass fractionation, through the combined use of atomically dispersed Co catalyst and acid co-catalyst.

The effects of supported Pd, Pt, Re, Rh, Ru, Ir, Au, and Ni catalysts on renewable hydrocarbon production from alternative feedstock

Screening tests of supported commercial and prepared Pd, Pt, Re, Rh, Ru, Ir, Au (5%), and Ni (5–65%) metal catalysts were conducted under one-pot solvent-free hydrotreating (HT) conditions to evaluate their activity, selectivity, and potential for renewable hydrocarbon (RH) production from rapeseed oil (RO). Catalysts were characterized by XRF, XRD, FE-SEM, TEM, and N2 sorption analysis. Composition of RO, liquid, and gaseous products were analyzed by GC-FID, GC-MS, C, H, N, S elemental analysis, FT-IR, and GC-TCD. Full conversion of RO with RH yield up to 85% were achieved over most active supported commercial Ni (65%) and Re, Rh, Ru (5%) catalysts in short residence time (up to 10 min) under relatively mild reaction temperature 340 °C and initial H2 pressure 10 MPa. Noticeable effect of Ru catalysts on cleavage of -C-C- bond reactions make them promising for practical application in RH synthesis. Multi-function SiO2–Al2O3 supported Ru (5%) catalyst (Ru5SAp) prepared by developed simple method is perspective for wide molecular weight hydrocarbon production by –CC- hydrogenation, oxygen removal and cleavage of -C-C- bonds including ring opening reactions for structure modification of different raw materials – fats, oils, phenols, and fossil based feedstocks. Benzene, toluene, tetralin, guaiacol, and n-nonadecane were used as model compounds for investigation of catalytic effects. Ru5SAp possesses similar performance as most active supported commercial noble metal catalysts in HT process of RO. It is reusable up to three HT reaction cycles although deactivation of catalyst causes significant changes in obtained hydrocarbon composition.

Stimulated Raman scattering of H2 in hollow-core photonics crystal fibers pumped by high-power narrow-linewidth fiber oscillators.

The stimulated Raman scattering (SRS) process in gas-filled hollow-core fiber is mostly used to realize the wavelength conversion, which has the potential to produce narrow-linewidth and high-power fiber laser output. However, limited by the coupling technology, the current research is still at a few watts power level. Here, through the fusion splicing between the end-cap and the hollow-core photonics crystal fiber, several hundred watts pump power can be coupled into the hollow core. Homemade narrow-linewidth continuous wave (CW) fiber oscillators with different 3 dB linewidths are used as the pump sources, then the influences of the pump linewidth and the hollow-core fiber length are studied experimentally and theoretically. As the hollow-core fiber length is 5 m the H2 pressure is 30 bar, 109 W 1st Raman power is obtained with a Raman conversion efficiency 48.5%. This study is significant for the development of high-power gas SRS in hollow-core fibers.

Reductive Catalytic Fractionation of Abies Wood into Bioliquids and Cellulose with Hydrogen in an Ethanol Medium over NiCuMo/SiO2 Catalyst

Noble metal-based catalysts are widely used to intensify the processes of reductive fractionation of lignocellulose biomass. In the present investigation, we proposed for the first time using the inexpensive NiCuMo/SiO2 catalyst to replace Ru-, Pt-, and Pd-containing catalysts in the process of reductive fractionation of abies wood into bioliquids and cellulose products. The optimal conditions of abies wood hydrogenation were selected to provide the effective depolymerization of wood lignin (250 °C, 3 h, initial H2 pressure 4 MPa). The composition and structure of the liquid and solid products of wood hydrogenation were established. The NiCuMo/SiO2 catalyst increases the yield of bioliquids (from 36 to 42 wt%) and the content of alkyl derivatives of methoxyphenols, predominantly 4-propylguaiacol and 4-propanolguaiacol. A decrease in the molecular mass and polydispersity (from 1870 and 3.01 to 1370 Da and 2.66, respectively) of the liquid products and a threefold increase (from 9.7 to 36.8 wt%) in the contents of monomer and dimer phenol compounds were observed in the presence of the catalyst. The solid product of catalytic hydrogenation of abies wood contains up to 73.2 wt% of cellulose. The composition and structure of the solid product were established using IRS, XRD, elemental and chemical analysis. The data obtained show that the catalyst NiCuMo/SiO2 can successfully replace noble metal catalysts in the process of abies wood reductive fractionation into bioliquids and cellulose.

Synthesis of Alumina Supported Pt-SnO2 Hybrid Nanostructures by In Situ Transformation of PtSn Alloy Nanoparticles and Their Application as Highly Efficient Catalysts for Selective Hydrogenation of Furfural

In this work, PtSn alloy nanoparticles were synthesized by coreduction of Pt and Sn precursors by ethylene glycol in the presence of stabilizing agents and then were in situ transformed into Pt-SnO2 hybrid nanostructures on alumina supports by calcination. Relative to Pt/Al2O3, Pt1-(SnO2)0.3/Al2O3 demonstrates improved catalytic efficiency for furfuryl alcohol production by furfural hydrogenation. Under the H2 pressure of 1.0 MPa, 100 °C, 3.0 h, and furfural/Pt molar ratio of 1435/1, the furfuryl alcohol yields could approach 98.2%. The enhancement of catalytic performance of the Pt-SnO2/Al2O3 could be ascribed to the formation of the close contact Pt-SnO2 interfaces, which is highly active for furfural hydrogenation due to the synergistic effect between Pt and SnO2.

Solvent-Free Catalytic Hydrotreatment of Alcell Lignin Using Mono- and Bimetallic Ni(Mo) Catalysts Supported on Mesoporous Alumina

Technical lignins are an attractive and renewable source for the production of aromatic chemicals. However, efficient depolymerization of technical lignins to valuable low-molecular-weight chemicals is challenging due to its recalcitrant nature. Here, we report the use of nonprecious metal-based, monometallic Ni (prereduced) and bimetallic NiMo (in situ sulfided) catalysts supported on mesoporous alumina, either as such or doped with Si, Mg, or Ti, for a solvent-free catalytic hydrotreatment (batch, 400 °C, 4 h reaction time, 100 bar initial H2 pressure) of Alcell lignin to obtain oils enriched in biobased chemicals like alkylphenols and the parent phenol. These are important building blocks in the chemical industry and are currently obtained from fossil resources. The catalysts were prepared by a one-pot evaporation-induced self-assembly (EISA) method and characterized by various techniques [N2 physisorption, X-ray diffraction (XRD), temperature-programmed desorption (TPD), temperature-programmed reduction (TPR), and transmission electron microscopy (TEM)]. The best result was obtained using a monometallic Ni catalyst with an ordered mesoporous alumina support doped with Ti, giving an oil yield of 57 wt % with 10 wt % alkylphenols on lignin intake. By comparison, it was shown that the mesoporous structure of alumina is crucial for enhanced lignin oil yields.

Enhanced hydrogen properties of MgH2 by Fe nanoparticles loaded hollow carbon spheres

In the present investigation, we have reported the synergistic effect of Fe nanoparticles and hollow carbon spheres composite on the hydrogen storage properties of MgH2. The onset desorption temperature for MgH2 catalyzed with hollow carbon spheres and Fe nanoparticle (MgH2-Fe-HCS) system has been observed to be 225.9 °C with a hydrogen storage capacity of 5.60 wt %. It could be able to absorb 5.60 wt % hydrogen within 55 s and desorb 5.50 wt % hydrogen within 12 min under 20 atm H2 pressure at 300 °C. The desorption activation energy of MgH2-Fe-HCS has been found to be 84.9 kJ/mol, whereas the desorption activation energies for as received MgH2, Hollow carbon sphere catalyzed MgH2 and Fe catalyzed MgH2 are found to be 130 kJ/mol, 103 kJ/mol, and 94.2 kJ/mol respectively. MgH2-Fe-HCS composite lowered the change in enthalpy of hydrogen desorption from MgH2 by 20.02 kJ/mol as compared to pristine MgH2. MgH2-Fe-HCS shows better cyclability up to 24 cycles of hydrogenation and dehydrogenation of MgH2. The mechanism for the better catalytic action of Fe and HCS on MgH2 has also been discussed.

Simultaneous Pd Nanoparticle Deposition and Enhancement in the Surface Oxygen Vacancy of Bi2MoO6 Nanoflakes for Room Temperature Vanillin Hydrodeoxygenation

A promising method for transforming lignin derivatives into high-value chemicals and biofuels is hydrodeoxygenation (HDO), which is anticipated to be a viable and feasible protocol for the biorefinery. Nonetheless, the requirements of high temperature and high H2 pressure are two main hurdles in the HDO process. Herein, we developed highly active Pd-decorated Bi2MoO6 nanoflakes for complete and selective vanillin (a typical lignin-derived platform molecule) conversion at room temperature and mild H2 pressure. The acquired results reveal that the selection of solvents in vanillin HDO has a detrimental effect, specifically on the product selectivity. When the reaction was performed in dichloromethane solvent, 2-methoxy-4-methylphenol (MMP) was obtained after a 4 h reaction with >99% vanillin conversion and >99% MMP selectivity. Conversely, if water is the reaction medium, it suppresses the formation of MMP, resulting in the selective formation of vanillin’s hydrogenation product vanillyl alcohol (VOL) with 88% vanillin conversion and 91% VOL selectivity. X-ray photoelectron spectroscopy (XPS), Raman, Fourier transform infrared (FT-IR), and ultraviolet (UV)–visible adsorption experimental studies revealed that the superior catalytic performance of the presented catalyst was due to the efficient adsorption of the reactant preferentially through the aldehyde moiety over the catalyst surface and enhancement in surface oxygen vacancies (SOVs) of bismuth molybdate nanoflakes as a result of the treatment with NaBH4 used for Pd nanoparticle deposition. No significant loss in the catalytic activity after multiple cycles proves the stability and good recyclability of the proposed catalyst. This study improves the catalysis strategy of HDO of lignin derivatives and paves the path toward the development of advanced and highly efficient metal-based catalysts for valuable fuels and chemical production from biomass under mild conditions.

Poly(ethylene imine) stabilized metal hydroxide nanoaggregates in reverse microemulsion system enabling synthesis of hollow silica catalytic nanoreactors as highly efficient semihydrogenation catalysts

In this work, we report a generic method of reverse microemulsion for syntheses of uniform and well-dispersed hollow porous silica nanospheres with metal (oxide) nanoparticles inside their cavities (MxOy@HPSNs or M@HPSNs), where the water phase consists of poly(ethylene imine) stabilized metal hydroxide nanoaggregates. During silica deposition, the mentioned nanoaggregates function as void templates as well as a platform to deliver catalytic functionality into voids. The subsequent calcination simultaneously gives hollow nanostructures and metal (oxide) nanoparticles inside central voids. The method applies to the metals that have hydroxide precipitates at basic conditions, and is suitable for most of catalytically active metals. As a demonstration, Pd@HPSNs illustrate high catalytic efficiency for selective hydrogenation of phenylacetylene at ambient H2 pressure, and the enhancement could be assigned to the effect of void confinement.

Water Formation Kinetics on Co(0001) at Low and Near-Ambient Hydrogen Pressures in the Context of Fischer–Tropsch Synthesis

Understanding the kinetics of oxygen removal from catalytically active metal surfaces by hydrogen is important for several catalytic reactions such as Fischer–Tropsch synthesis, methanation of CO or CO2, and the reverse-water–gas-shift reaction. Motivated by FTS, a Co(0001) single crystal model catalyst was used to study the kinetics of oxygen removal through reaction with hydrogen. Kinetic studies in the 10–7–10–4 mbar H2 pressure regime show that water formation is first order in the surface hydrogen concentration while the order in oxygen concentration changes from one at low oxygen coverage to zero at high oxygen coverage. In situ XPS shows that the hydrogen surface concentration saturates around 10–1 mbar and on this basis the typical temperature of 450 K needed for water formation in this pressure regime can be considered as typical for high pressures as well. The absence of OH buildup during the reaction points to O + H as the rate-limiting step, with a barrier of ∼120 kJ mol–1. Such a high barrier shows that slow removal of adsorbed oxygen from the surface of reactive metal catalysts such as cobalt may be rate-limiting for the overall reaction.

Pd nanoparticles encapsulated in MOF boosts selective hydrogenation of biomass derived compound under mild conditions

Catalytic conversion of biomass-derived compounds into value-added chemicals or liquid fuels is of significant importance for the valorization of sustainable biomass. Currently, selective hydrogenation of typical biomass-derived 5‑hydroxymethylfurfural (HMF) to the valuable 2,5-dihydroxymethyl-tetrahydrofuran (DHMTHF) has attracted considerable interest, but still suffers from the low efficiency and harsh H2 pressure (usually 4 ∼ 8 MPa) in this process. Therefore, developing more efficient catalysts for the facile synthesis of DHMTHF from HMF under mild conditions is highly desired. Herein, small Pd nanoparticles were encapsulated in a metal–organic framework (Pd@MOF-303), and highly stabilized by the adjacent pair of N atoms of organic linkers of MOF-303. The small Pd nanoparticles were significantly efficient for HMF conversion to DHMTHF, and exhibited a yield of 95.8 % with a production rate of 85.1 h−1 under 1 MPa H2. The excellent catalytic performance was attributed to the small Pd nanoparticles which could expose more stable defective sites that were highly active and selective for this reaction.

Temperature dependence of hydrogen isotope effect in LaNi5-H(D) system

To study inverse effect of hydrogen isotopes in LaNi5 for hydrogen isotope separation at ambient temperature, temperature dependence of hydrogen isotope effect in LaNi5－H(D) system was investigated in the temperature range -70 °C to 3 °C. Isotherms of hydrogen isotopes were tested in an automated Sieverts apparatus with a thermostat, and pressure differences were studied between H2 and D2. Isotope exchange process was carried out and H2－HD－D2 equilibrium was judged by online chromatography, separation factors were calculated to investigate the thermodynamic isotope effect. In the H2, D2 isotherms, average time interval (0.5h) between each equilibrium point was relatively short due to high precision temperature control. From the plateau pressures at a constant hydrogen (or deuterium) concentration in LaNi5 (2D or 2H atoms/mole of LaNi5) the partial molar enthalpies, ⊿H, and entropies, ⊿S of formation were calculated. ⊿H and ⊿S kept good accordance with the values from references, which indicated good performance of the Sieverts apparatus. The isotope exchange equilibrium was reached within 1h. The results showed that ratio between H2 pressure and D2 pressure, r(H－D) = P(D2)/P(H2), dropped as temperature decreased and the inverse effect was found (r(H－D)<1.0) below -5 °C according to the absorption branch of isotherms, whereas the effect was estimated to appear below 60 °C from the desorption branch. The separation factor of the H2－HD－D2 mixture, decreased as temperature increased and the inverse effect happened below -20 °C. The inverse effect was affected by the isotherm hysteresis and HD existence.

Nickel-Alumina Catalysts for the Transformation of Vegetable Oils into Green Diesel: The Role of Preparation Method, Activation Temperature, and Reaction Conditions.

Two nickel alumina catalysts containing 60 wt. % Ni were synthesized by wet impregnation and co-precipitation in order to study the effect of preparation methods on the catalytic efficiency concerning the transformation of sunflower oil into green diesel. The effect of activation temperature on the catalytic efficiency of the most active catalyst was also studied. The catalysts were characterized using various techniques and which were evaluated in the aforementioned reaction using a semi-batch reactor. The catalyst prepared by co-precipitation exhibited a higher specific surface area and smaller mean crystal size of the nickel nanoparticle (higher nickel metallic surface). These justify its higher efficiency with respect to the corresponding catalyst synthesized by wet impregnation. The increase in the activation temperature from 400 to 600 °C increased the size of the nickel nanoparticles through sintering, thus destroying the small pores. These led to a decrease in the nickel surface and specific surface area and, thus, to a decrease in the catalytic efficiency. The optimization of the reaction conditions over the most active catalyst (prepared by co-precipitation and activated at 400 °C) leads to the complete transformation not only of the sunflower oil (edible oil) but also of waste cooking oil (non-edible oil) into green diesel. The liquid produced after the hydrotreatment for these two feedstocks for 7 h, at H2 pressure 40 bar and temperature 350 °C using 100 mL of oil and 1 g of catalyst was composed of 97 and 96 wt. % of green diesel, respectively.

Selective Hydrogenation of Pyridine and Derivatives of It on Bimetallic Catalysts Modified with Chitosan

A study is performed of the catalytic properties of bimetallic nanoparticles based on palladium and a base metal (silver or copper) supported on alumina modified with chitosan in the selective hydrogenation of pyridine and derivatives of it with the formation of piperidine and derivatives of it. It is shown that the effect of increasing the activity of bimetallic nanoparticles is due to the small size of particles (2–3 nm), compared to the monometallic palladium catalyst. It is established that the conversion of pyridine reaches 99% with 99% selectivity toward piperidine under mild conditions (60°C; H2 pressure, 70 atm).

Minimizing the Lag Phase of Cupriavidus necator Growth under Autotrophic, Heterotrophic, and Mixotrophic Conditions.

Cupriavidus necator has the unique metabolic capability to grow under heterotrophic, autotrophic, and mixotrophic conditions. In the current work, we examined the effect of growth conditions on the metabolic responses of C. necator. In our lab-scale experiments, autotrophic growth was rapid, with a short lag phase as the exponential growth stage was initiated in 6 to 12 h. The lag phase extended significantly (>22 h) at elevated O2 and CO2 partial pressures, while the duration of the lag phase was independent of the H2 or N2 partial pressure. Under heterotrophic conditions with acetate as the organic substrate, the lag phase length was short (<12 h), but it increased with increasing acetate concentrations. When glucose and glycerol were provided as the organic substrate, the lag phase was consistently long (>12 h) regardless of the examined substrate concentrations (up to 10.0 g/L). In the transition experiments, C. necator cells showed rapid transitions from autotrophic to heterotrophic growth in less than 12 h and vice versa. Our experimental results indicate that C. necator can rapidly grow with both autotrophic and heterotrophic substrates, while the lag time substantially increases with nonacetate organic substrates (e.g., glucose or glycerol), high acetate concentrations, and high O2 and CO2 partial pressures. IMPORTANCE The current work investigated the inhibition of organic and gaseous substrates on the microbial adaption of Cupriavidus necator under several metabolic conditions commonly employed for commercial polyhydroxyalkanoate production. We also proposed a two-stage cultivation system to minimize the lag time required to change over between the heterotrophic, autotrophic, and mixotrophic pathways.

Selective Amination of Benzaldehyde over the Fine Ru Nanoparticles Anchored in NiO Catalysts

The selective amination of benzaldehyde (BZH) is one of the important industrial reactions for the production of fine chemicals. Herein, we synthesized a Ru/NiO nanocatalyst with an extremely low loading of noble metals (0.22%) via a facile ball-milling method efficient for the conversion of BZH to N-benzylidenebenzylamine (N-BDB). Compared with the benchmark im-Ru/NiO catalyst prepared via the traditional impregnation (im) method, the Ru/NiO catalyst exhibited the higher yield of N-BDB, with a full conversion of BZH and a 91.5% selectivity to N-BDB in 0.1 MPa NH3 and 2 MPa H2 pressure. After that, various parameters that influenced the catalytic performance and potential reaction pathway were investigated. In addition, the catalyst maintained high stability, which could be recycled even for five runs without obvious deactivation. Extensive characterizations verified that the H2 activation ability of Ru and the overall acidity of the Ru/NiO catalyst were improved, which should account for the superior catalytic performance. This work provides a facile strategy of catalyst synthesis for the selective production of fine chemicals.

Transesterification and Hydrotreating Reactions of Rice Bran Oil for Bio-Hydrogenated Diesel Production

Two different methods of production of bio-hydrogenated diesel (BHD), simply called green diesel from rice bran oil (RBO), were performed. In the first route, a direct hydrotreating reaction of RBO to BHD catalysed by Pd/Al2O3 was performed in a high-pressure batch reactor. Operating conditions were investigated as follows: catalyst loading (0.5 to 1.5% wt.), temperature (325 to 400 °C), initial hydrogen (H2) pressure (40 to 60 bar) and reaction time (30 to 90 min). The optimal condition was obtained at 1% wt catalyst loading, 350 °C, 40 bar H2 pressure and 60 min. Yields of crude/refined biofuels and BHD achieved were approximately 98%, 81.71% and 73.71%, respectively. In another route, transesterification together with hydrotreating reactions of rice bran methyl ester (RBME) to BHD was performed using the optimal conditions obtained from the first route. The amount of 98% crude biofuel was obtained and was equivalent to production yields of refined biofuel (85.71%) and BHD (68.51%). Furthermore, physical and chemical properties of both RBO/RBME green diesel were also considered following ASTM standard methods. In summary, both catalytic reactions were achieved in the range of a low-speed industrial diesel and were further recommended for BHD or green diesel production from RBO.

Active Pd Catalyst for the Selective Synthesis of Methylated Amines with Methanol.

Selective N-methylation of amines with methanol is an important reaction in the synthesis of high-value-added fine chemicals, including dyes, surfactants, pharmaceuticals, agrochemicals, and materials. However, N-methylated amines possess higher reactivities and are prone to further transform into N,N-dimethylated amines. Therefore, it is still a challenge to controllably regulate the selectivity of N-methylation using heterogeneous catalysts without the use of base. Herein, we developed a series of Pd/Zn(Al)O catalysts with abundant basic sites, and the selectivity of N-methylation was controlled by a heterogeneous Pd/Zn(Al)O catalyst with a Zn/Al ratio of 10 and a Pd loading of 0.4 wt % in the pressure of H2. The experimental results showed that the appropriate basic properties of the catalyst were beneficial to form the desired N-methylated amine. The low loading of Pd in the catalyst was highly dispersed on the support, providing sufficient active sites. These were attributed to the Zn vacancies formed by Al-doped Zn, which were beneficial to form the highly active and stable Pd sites. Furthermore, a series of amines and nitrobenzenes with different functional groups were well tolerated for the selective synthesis of N-methylated amines in the absence of base.

Guaiacol to Aromatics: Efficient Transformation over In Situ-Generated Molybdenum and Tungsten Oxides

The development of catalysts for the hydrodeoxygenation of bio-based feedstocks is an important step towards the production of fuels and chemicals from biomass. This paper describes in situ-generated bulk molybdenum and tungsten oxides in the hydrodeoxygenation of the lignin-derived compound guaiacol. The catalysts obtained were studied using powder X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transition electron microscopy, diffuse reflectance infrared Fourier transform spectroscopy, and Raman spectroscopy. The use of metal carbonyls as precursors was shown to promote the formation of amorphous molybdenum oxide and crystalline tungsten phosphide under hydrodeoxygenation conditions. The catalysts’ activity was investigated under various reaction conditions (temperature, H2 pressure, solvent). MoOx was more active in the partial and full hydrodeoxygenation of guaiacol at temperatures of 200–380 °C (5 MPa H2, 6 h). However, cyclohexane, which is an undesirable product, was formed in significant amounts using MoOx (5 MPa H2, 6 h), while WOx was more selective to aromatics. When using dodecane as a solvent (380 °C, 5 MPa H2, 6 h), the benzene-toluene-xylenes fraction was obtained with a 96% yield over the WOx catalyst.