Performance Of Catalysts Research Articles

The Effects of Internal Electron Donors on MgCl2-Supported Ziegler–Natta Catalysts for Isotactic PP

The electron donors (ED) in Ziegler–Natta (Z-N) catalysis are classified as internal electron donors (IED) and external electron donors (EED), and both IED and EED are indispensable components for enhancing the catalytic reactivity and regulating the stereoregularity of polyolefinic materials in a typical industrial Z-N catalytic process. With the intensive research on ED, the Z-N catalyst performances have experienced successive progress in the last few decades. Polypropylenes (PP) as a commodity polyolefin material, especially the isotactic PP (iPP), are produced in multi-billion pounds per annum by utilization of the various IED- and EED-assisted Z-N catalysts systems. In the course of developing Z-N catalysts, the ED constitutes a key component of the content and represents a significant area of future research. In this review, we introduced a concise overview of the functions of IEDs in the generations of Z-N catalyst systems and the widely used IED types (A total of 11 different types of IEDs are encompassed within this study) that have been developed so far. In addition, we focused on the coordination modes of different IEDs in the MgCl2-supported Z-N catalyst system and analyzed the effects of different types of IEDs on the PP isotacticity, regioselectivity, hydrogen sensitivity, and briefly introduced the application of environmentally friendly rosinate and salicylate IEDs.

Oxidative Desulfurization of Kerosene in Batch Reactor using Magnetite Mesoporous Silica Composite Zeolite Catalyst

The petroleum refining sector has increasingly prioritized the creation of clean fuel as a crucial priority. The objective of this project is to generate environmentally friendly fuel through the use of a straightforward and uncomplicated method. Using a novel synthetic nano-catalyst, batch oxidative desulfurization (ODS) eliminates sulfur compounds in Kerosene. The new Catalyst's silica nano-particle support is initially manufactured utilizing the sol-gel technique. Subsequently, the support is employed to fabricate a synthetic composite nano-catalyst composed of ferric oxide, utilizing the techniques devised for extracting a novel synthetic handcrafted (Fe2O3/composite support) Nano-catalyst. The composite supports used for the robust studies on the desulfurization process contain different levels of HY-zeolite (100 percent Nano silica). These levels include 10% HY-zeolite + 90% Nano silica, 20% HY-zeolite + 80% Nano silica, and 30% HY-zeolite + 70% Nano silica. The supports and manufactured Catalyst underwent characterization tests, including SEM, XRD, XRF, TGA, FTIR, BET, and particle size distribution. The tests showed an ideal distribution of the active metal (Fe), different surface structures, and a high active metal dispersion were achieved. The prominent locations are identified as limited in number, and the catalysts exhibit metal-support solid interaction. The existing Catalyst's performance was evaluated using a batch reactor. The assessment involved testing the Catalyst at different reaction temperatures (303 to 393 K) and batch times (30 to 120 minutes) while varying HY-zeolite quantities in the composite supports.

Edge sites regulation, strain and electric field effect on MoS2/CoS2 heterojunction catalysts for hydrogen evolution reaction.

Heterojunction catalysts in the field of hydrogen evolution reaction (HER) from electrocatalytic water splitting have recently become a hot research topic. In this paper, we systematically calculated the HER catalytic performance of a MoS2/CoS2 heterojunction for the first time, considering the effect of edge sites regulation, strain and electric field. The results indicate that the MoS2/CoS2 heterojunction exhibits synergistic catalytic performance compared to MoS2 and CoS2, the HER catalytic activity of which can be improved by exposing more edge sites or regulating the S content on the edges, with an optimized ratio of 25%. Surprisingly, applying strain has a slight effect on the catalytic activity of the edge, however, an obvious effect on the basal plane. For example, applying 2% tensile strain on the MoS2/CoS2 heterojunction can improve the edge catalytic performance by 13%, and for the basal plane, this value can reach 92%. In this case, the catalytic performance of the basal plane is better than that of the edge with 2% and without strain. Since the basal plane accounts for the majority of the two-dimensional catalysts, the catalytic performance of the basal plane is generally much lower than that of the edge. This discovery is of great significance, which means by adjusting strain, the catalytic performance of the heterojunction catalyst is likely to be improved by orders of magnitude. Moreover, considering the actual experimental process, we also calculated the effect of the electric field and found that 0.7 V/Å electric field can enhance the HER catalytic activity of the MoS2/CoS2 heterojunction by 23%.

Recent Progress on Stability of Layered Double Hydroxide-Based Catalysts for Oxygen Evolution Reaction

Water electrolysis is regarded as one of the most viable technologies for the generation of green hydrogen. Nevertheless, the anodic oxygen evolution reaction (OER) constitutes a substantial obstacle to the large-scale deployment of this technology, due to the considerable overpotential resulting from the retardation kinetics associated with the OER. The development of low-cost, high-activity, and long-lasting OER catalysts has emerged as a pivotal research area. Layered double hydroxides (LDHs) have garnered significant attention due to their suitability for use with base metals, which are cost-effective and exhibit enhanced activity. However, the current performance of LDHs OER catalysts is still far from meeting the demands of industrial applications, particularly in terms of their long-term stability. In this review, we provide an overview of the causes for the deactivation of LDHs OER catalysts and present an analysis of the various mechanisms employed to improve the stability of these catalysts, including the synthesis of LDH ultrathin nanosheets, adjustment of components and doping, dissolution and redeposition, defect creation and corrosion, and utilization of advanced carbon materials.

Optimizing H-B-ZSM-5 catalyst for efficient methanol-to-propylene conversion via precise control of NaOH-TPABr interaction

This study investigates the effects of boron (B) and crucial interplay between NaOH and TPABr during the synthesis of seed-induced H-B-ZSM-5 for designing effective MTP catalysts. Various characterization techniques were employed to examine the impact of these factors on the physiochemical properties of the synthesized catalysts. The findings reveal that boron incorporation leads to an 81 % increase in catalyst stability and a 5.5 % increase in selectivity to light olefins. A critical interplay between NaOH concentration and TPABr content was also found in optimizing crystallinity, morphology, acidity and surface area. The crystallinity, Al distribution homogeneity, and average pore size initially increase before decreasing with increasing NaOH concentration. The research highlights the pivotal role of TPABr, which interacts with NaOH to profoundly impact catalyst performance. The synthesized catalyst H-B-ZSM-5, prepared with TPABr/20SiO2 = 0.65 and Na2O/20SiO2 = 1.69, exhibits excellent performance, achieving 99 % conversion and 83 % light olefin selectivity with minimal byproduct formation during a 170-h test at a high WHSVmethanol equal to 8 h−1.

Prediction of catalytic performance of metal oxide catalysts for alkyne hydrogenation reaction based on machine learning

In the field of catalyst design, machine learning is gaining significant attention, especially in situations where data is limited. Facing this challenge, we have developed a neural network model that enhances predictive accuracy through the careful selection of catalyst descriptors and feature engineering, aiming to predict the conversion rate and selectivity of the acetylene semi-hydrogenation reaction. Our model has identified promising metal oxide catalysts, such as CuO, ZnO, and V2O5, for the acetylene semi-hydrogenation reaction, and these predictions have been experimentally validated. Among them, CuO achieved an acetylene conversion of 99.6 % and an ethylene selectivity of 90 % at 50–100°C, which is unprecedented at the reaction space velocity we tested. This high activity at relatively low temperatures indicates a more promising industrial application. Looking ahead, machine learning will play a pivotal role in catalyst design, accelerating the discovery and industrial application of new materials.

Ethylene/Styrene Copolymerization by (Me3SiC5H4)TiCl2(O-2,6-iPr2-4-RC6H2) (R = H, SiEt3)-MAO Catalysts: Effect of SiMe3 Group on Cp for Efficient Styrene Incorporation.

The synthesis and structural analysis of (Me3SiC5H4)TiCl2(OAr) [OAr = O-2,6-iPr2-4-RC6H2; R = H, SiEt3] revealed that it exhibits higher catalytic activities than (tBuC5H4)TiCl2(OAr), Cp*TiCl2(OAr), with efficient comonomer incorporation in ethylene/styrene copolymerization in the presence of a methylaluminoxane (MAO) cocatalyst. The catalytic activity in the copolymerization increased upon increasing the charged styrene concentration along with the increase in the styrene content in the copolymers, whereas the activities of other catalysts showed the opposite trend. (Me3SiC5H4)TiCl2(O-2,6-iPr2C6H3) displayed the most suitable catalyst performance in terms of its activity and styrene incorporation, affording amorphous copolymers with styrene contents higher than 50 mol% (up to 63.6 mol%) and with random styrene incorporation confirmed by 13C-NMR spectra.

Data-driven catalyst design for oxidative dehydrogenation of propane with CO2 using decision tree regression

Interpretable machine learning (ML) techniques have made significant progress in the design of high-performance materials. Here we employ decision tree (DT) models to discover and optimize multicomponent catalysts for the oxidative dehydrogenation of propane with CO2 (ODPC). While DT models have been used to improve a single target variable, this study leverages interpretable models by simultaneously considering the criteria for improving all the multiple target variables of ODPC, namely C3H8 conversion, CO2 conversion, and C3H6 yield. Instead of using literature data, we establish a consistent laboratory-scale database, and DT models are trained on multiple target variables representing catalytic performance. The trained DT models identify key input variables, including active metals, compositions, and support materials and provide criteria in the form of inequalities for the design of new ODPC catalysts. Despite using a database of binary and ternary metal oxides only, the fulfilment of all criteria suggests quaternary metal oxides with Cr, Ni, Mo, and ZrOx. The DT-proposed multicomponent catalysts show superior ODPC performance to the database catalysts, with a synergistic effect between the active elements. This exploitation of the relationship information between catalyst components and performance highlights the benefit of interpretable ML techniques in the design of high-performance multicomponent catalysts.

The impact of transition metals (Cr, Mn, and Co) on the performance of the 10%Ni/Al2O3-10%CeO2 catalysts in combined CO2 reforming and partial oxidation of methane

This study explores the efficacy of Cr, Mn, and Co promoters in enhancing the performance of 10%Ni/Al2O3-10%CeO2 catalysts during methane combined reforming process, emphasizing improved metal dispersion and reduced carbon formation. The supports and catalysts were synthesized through mechanochemical and impregnation methods, respectively, and characterized using XRD, BET, TPR, TPO, and FESEM analyses. The synthesized catalysts exhibited a high BET surface area, ranging from 195 to 172 m2 g-1, along with a mesoporous structure characterized by pore sizes between 2 and 12 nm. The introduction of Cr significantly enhanced catalyst performance, resulting in 70.5 % CH4 and 69.1 % CO2 conversions in dry reforming. TPO analysis indicated reduced carbon deposition on promoted catalysts by enhancing Ni dispersion and carbon reactivity. The 10%Ni–3%Cr/Al2O3-10%CeO2 catalyst demonstrated stability over 440 min at 700 °C, achieving 84.9 % CH4 and 68.1 % CO2 conversions in combined reforming. The TPO analysis indicated an absence of carbon deposition on the catalyst surface during combined reforming, which was corroborated by the FESEM analysis. Furthermore, the influence of operating parameters on catalyst efficiency in both dry and combined reforming processes was investigated. As GHSV increased from 8000 to 24,000 ml/h.gcat, CH4 conversion declined in dry reforming and combined reforming, dropping from 77 % to 66 % and from 86 % to 84 %, respectively. Also, in both processes, increasing the oxidizer contents (CH4: CO2 from 2:1 to 1:2, CH4: CO2: O2 from 1:1:0 to 1:1:0.35) led to an increase in CH4 conversion, while CO2 conversion decreased.

Modulating Silver Performance in Electrocatalytic Oxidation of HCHO via SMSI between Ag-Co3O4 Interfaces.

The replacement of oxygen evolution reactions with organic molecule oxidation reactions to enable energy-efficient hydrogen production has been a subject of interest. However, further reducing reaction energy consumption and releasing hydrogen from organic molecules continue to pose significant challenges. Herein, a strategy is proposed to produce hydrogen and formic acid from formaldehyde using Ag/Co3O4 interface catalysts at the anode. The key to improving the performance of Ag-based catalysts for formaldehyde oxidation lies in the strong SMSI achieved through the well-designed "spontaneous redox reaction" between Ag and Co3O4 precursors. Nano-sized Ag particles are uniformly dispersed on Co3O4 nanosheets, and electron-deficient Agδ+ are formed by the SMSI between Ag and Co3O4. Ag/Co3O4 demonstrates exceptional formaldehyde oxidation activity at low potentials of 0.32V versus RHE and 0.65V versus RHE, achieving current densities of 10 and 100mA cm-2, respectively. The electrolyzer "Ag/Co3O4||20% Pt/C" achieves over 195% hydrogen efficiency and over 98% formic acid selectivity, maintaining stable operation for 60 hours. This work not only presents a novel approach to precisely modulate Ag particle size and interface electronic structure via SMSI, but also provides a promising approach to efficient and energy-saving hydrogen production and the transformation of harmful formaldehyde.

An efficient product design tool for aftertreatment system

A numerical simulation technique based on the conservation of mass and energy in the gas phase has been developed to optimize the aftertreatment system with the lowest costs. Both oxygen storage capacity model and catalyst deterioration model have been integrated into the three-way catalyst performance model. Applications have been discussed, including XY-L 1.5L I3 gasoline turbocharged direct injection (GTDI) production hybrid vehicle, BY-L 1.5L I4 GTDI hybrid vehicle, XY-L (overseas version) 1.5L I4 GTDI hybrid vehicle, and G-L7 1.5L I4 GTDI hybrid vehicle. Vehicle tests in support of the proposed model have been described. The developed model covers the complete range of the cold start, high temperature and volume flow conditions. To optimize a three-way catalyst performance, this work simulated the effect of air fuel ratio, space velocity, temperature, biasing adjustment on the catalyst efficiency. The simulations presented the technique’s capability of well predicting emissions on fresh and full useful life aged aftertreatment systems, respectively, and carried out under transient conditions. The investigation indicated that excess fueling was used upon engine start to heat the catalyst up to its full operating temperature of greater than 350°C. The model results prompted a redesign of the I3 and I4 1.5L GTDI China 6b, Euro VId and Tier 3/SULEV30 exhaust systems over the world light vehicle test procedure (WLTP) and federal test procedure (FTP) cycles, respectively, for example, the model suggested that the latest design for the SULEV30 aftertreatment system on XY-L (overseas version) 1.5L I4 GTDI hybrid vehicle with the revised calibrations in the areas of cold-start and closed-loop fuel treated emissions of NMOG, NOx, and CO to the 70% of the SULEV30 standards with a $64 cost reduction relative to the baseline.

Enhancing the performance of catalysts in turbulent premixed fuel-lean hydrogen/air combustion

Catalytic-aided combustion is a proven technique for burning highly lean and ultra-lean mixtures of hydrogen and air. However, the noble catalyst required for combustion is naturally scarce and therefore expensive. In this study, we focus on a numerical investigation to determine the best way of coating a platinum catalyst inside a catalytic hydrogen reactor. We study various planar and non-planar reactors and find that the reactor with a combination of half and full cylinders is the most effective in H2 conversion. Compared to an equivalent catalytic planar reactor, the non-planar configuration increases the H2 conversion by 30.7 %. The results show that enhancing mass and heat convection can significantly increase the H2 conversion. Furthermore, in a non-planar reactor, surfaces with an enhanced mass and heat transfer can achieve up to 50 % catalyst savings when coated with a catalyst, while still maintaining a conversion rate of 2 kg/s per unit of catalytically-coated surface area.

Integrating Multiple Strategies Using Biotechnology to Design High‐Performance Electrocatalysts for Hydrogen and Oxygen Evolution

AbstractCombining multiple design strategies often enhances catalyst performance but usually comes with high costs and low reproducibility. A technique that enhances catalyst performance in multiple strategies is urgently needed. Herein, a novel bioregulation technique is introduced, allowing simultaneous control over morphology, particle size, doping, interface engineering, and electronic properties. Bioregulation technique utilizes the soluble extracellular polymer from Aspergillus niger as a templating agent to construct high‐performance catalysts for hydrogen and oxygen evolution reaction (HER and OER). This technique controls catalyst morphology, introduces biological N and S doping, and regulates the electronic structure of the catalyst surface. Biomolecule modification enhances surface hydrophilicity, and the nanostructure increases surface roughness and gas‐release efficiency. Theoretical calculations show that the bioregulation technique shortens the d/p‐band center, optimizing reaction intermediate adsorption and desorption. The Bio‐Pt/Co3O4 catalyst with trace Pt on the surface, designed with these strategies, achieves HER (η10 of 42 mV), OER (η10 of 221 mV), and overall water‐splitting performance (1.51 V at 10 mA cm−2), maintaining stability for over 50 h, outperforming most Pt‐based catalysts. Notably, using spent lithium‐ion battery cathodes leachate, rich in Co2⁺, successfully replicates the experiment. This approach holds promise as a mainstream method for synthesizing high‐performance materials in the future.

Sequential-Flow Synthesis of Donepezil: A Green and Sustainable Strategy Featuring Heterogeneous Catalysis and Hydrogenation.

An atom-economical sequential-flow synthesis of donepezil, a widely prescribed drug for Alzheimer's disease, was accomplished using inexpensive, commercially available precursors. This achievement was made possible by reconfiguring the synthetic route to include only heterogeneous catalytic addition and condensation reactions, with a particular emphasis on skeletal transformation and bond formation through hydrogenation processes. Notably, water was the sole byproduct in this synthesis. A crucial aspect of this work was the development of appropriate continuous-flow processes to achieve a one-flow synthesis. This was accomplished by implementing in-line treatments of the main reaction stream to eliminate inhibitory factors that could affect catalyst performance in the hydrogenation steps.

Triple Regulations via Fe Redox Boosting Nitrate Reduction to Ammonia at Industrial Current Densities

Electrochemical nitrate reduction reaction (NO3‐RR) has promising prospects for green synthesis of ammonia and environmental remediation. However, the performance of catalysts at high current density usually suffers from the high energy barrier for the nitrate (NO3‐) to nitrite (NO2‐) and the competitive hydrogen evolution. Herein, we proposed a two‐step relay mechanism through spontaneous redox reaction followed electrochemical reaction by introducing low‐valence Fe species into Ni2P nanosheets to significantly enhance the NO3‐RR performance at industrial current density. The existence of low‐valence Fe species bypasses the NO3‐ to NO2‐ step through the spontaneous redox with NO3‐ to produce NO2‐ and Fe2O3, regulates the electronic structure of Ni2P to reduce the barrier of NO2‐ to NH3, thirdly prohibits the hydrogen evolution by consuming the excess active hydrogen through reduction of Fe2O3 to recover low‐valence Fe species. The triple regulations via Fe redox during the two‐step relay reactions guarantee the Fe‐Ni2P@NF high ammonia yield of 120.1 mg h‐1 cm‐2 with Faraday efficiency of more than 90% over a wide potential window and a long‐term stability of more than 130 h at ~1000 mA cm‐2. This work provides a new strategy to realize the design and synthesis of nitrate reduction electrocatalysts at high current densities.

Triple Regulations via Fe Redox Boosting Nitrate Reduction to Ammonia at Industrial Current Densities.

Electrochemical nitrate reduction reaction (NO3-RR) has promising prospects for green synthesis of ammonia and environmental remediation. However, the performance of catalysts at high current density usually suffers from the high energy barrier for the nitrate (NO3-) to nitrite (NO2-) and the competitive hydrogen evolution. Herein, we proposed a two-step relay mechanism through spontaneous redox reaction followed electrochemical reaction by introducing low-valence Fe species into Ni2P nanosheets to significantly enhance the NO3-RR performance at industrial current density. The existence of low-valence Fe species bypasses the NO3- to NO2- step through the spontaneous redox with NO3- to produce NO2- and Fe2O3, regulates the electronic structure of Ni2P to reduce the barrier of NO2- to NH3, thirdly prohibits the hydrogen evolution by consuming the excess active hydrogen through reduction of Fe2O3 to recover low-valence Fe species. The triple regulations via Fe redox during the two-step relay reactions guarantee the Fe-Ni2P@NF high ammonia yield of 120.1 mg h-1 cm-2 with Faraday efficiency of more than 90% over a wide potential window and a long-term stability of more than 130 h at ~1000 mA cm-2. This work provides a new strategy to realize the design and synthesis of nitrate reduction electrocatalysts at high current densities.

Coordination Desymmetrization of Copper Single-Atom Catalyst for Efficient Nitrate Reduction.

Coordination engineering strategy for optimizing the catalytic performance of single-atom catalysts (SACs) has been rapidly developed over the last decade. However, previous reports on copper SACs for nitrate reduction reactions (NO3RR) have mostly focused on symmetric coordination configurations such as Cu-N4 and Cu-N3. In addition, the mechanism in terms of the regulation of coordination environment and catalytic properties of SACs has not been well demonstrated. Herein, we disrupted the local symmetric structure of copper atoms by introducing unsaturated heteroatomic coordination of Cu-O and Cu-N to achieve the coordination desymmetrization of Cu-N1O2 SACs. The Cu-N1O2 SACs exhibit an efficient nitrate-to-ammonia conversion with a high FE of ~96.5 % and a yield rate of 3120 μg NH3 h-1 cm-2 at -0.60 V vs RHE. As indicated by in situ Raman spectra, the catalysts facilitate the accumulation of NO3 - and the selective adsorption of *NO2, which were further confirmed by the theoretical study of surface dipole moment and orbital hybridization. Our work illustrated the correlation between the coordination desymmetrization and the catalytic performance of copper SACs for NO3RR.

Synergistic magnetic Cu-Fe catalysts on N-doped biochar for efficient alkali lignin catalytic depolymerization into monophenols

Alkali lignin, a major by-product of papermaking, poses disposal challenges, hindering the full valorization of lignocellulose in sustainable biorefineries. One-pot lignin catalytic depolymerization (LDP) in water offers a promising route for producing valuable phenolic compounds. This study reports the successful synthesis of in-situ N-doped biochar supported CuxFey catalysts (CuxFey/N-BC) via a one-step carbothermal reduction method, enabling LDP in water without the need for external hydrogen, additives, alcohol solvent, or co-catalysts. Notably, the Cu5Fe1/N-BC could achieve remarkable catalytic performance under mild reaction conditions (280 °C, 6 h, 18 mL water), yielding 80.84±2.23 mg/g of monophenol, 56.17±1.32 % of bio-oil, and a lignin conversion rate of 80.66±0.73 %. This significantly surpassed the performance of monometallic catalysts and bare biochar. The synergistic effects of intermetallic interactions and nitrogen doping were proposed to create abundant active sites and rich pore structures, promoting efficient LDP reactions. Furthermore, the Cu5Fe1/N-BC exhibited excellent recyclability, with minimal activity loss (2.79 %) per cycle, due to its strong magnetism and favorable interactions. Mechanism investigation revealed that the Cu5Fe1/N-BC efficiently cleaved the C-O and C-C bonds in lignin, and led to the targeted production of guaiacyl phenols. This study provides valuable insights and practical strategy for valorizing lignin into valuable chemicals, advancing its utilization in various applications.

Rational Linker Design for Enhanced Performance of MOF-Derived Catalysts in Electrochemical Urea Synthesis.

2D metal-organic frameworks (2D MOFs) offer promising electrocatalytic potential for urea synthesis, yet the underlying reaction mechanisms and structure-activity relationships remain unclear. Using Cu-BDC as a model, density functional theory (DFT) calculations to elucidate these aspects are conducted. The results reveal a novel coupling mechanism involving *NO─CO and *NO─*ONCO, emphasizing the impact of linker modifications on Cu spin states and charge distribution. Notably, Cu-BDC-NH2 and Cu─BDC─OH emerge as promising catalysts. Additionally, structure-activity relationships through descriptors like d-band center, IE ratio, and L(Cu─O), providing insights for rational catalyst design is established. These findings pave the way for optimized catalysts and sustainable urea production, opening avenues for future research and technological advancements.

Investigation of ruthenium loaded beta zeolite catalyst performance in vanillin hydrodeoxygenation yielding both monomeric and dimeric cycloalkanes

The valorization of lignin-derived bio-oil is studied extensively due to its promising contribution to sustainability. Among these studies, many have focused on the hydrodeoxygenation (HDO) of phenolic model compounds as it is a crucial process in obtaining valuable oxygen-free hydrocarbons. In this work, vanillin HDO was performed on various bifunctional ruthenium-based zeolite catalysts with different zeolite supports (Y, ZSM-5, and beta) in a batch reactor. Ru-loaded beta zeolite catalysts (Ru/Hβ) exhibited the highest HDO activity among them, and the formation of dimeric cycloalkanes of high value were also observed specifically when using the Ru/Hβ catalyst. Due to their benefits of direct use in blending of biofuel, factors promoting the dimerization of phenolic monomers were extensively examined through a series of experiments using a mix of phenolic model compounds as HDO reactants. Specific oxygen containing functional groups contributed to the aldol condensation of aromatic species, and the structure and kinetic diameter of the monomers had a profound effect on the ability to participate in dimerization. Additionally, the metal loading of the catalyst and reaction conditions such as temperature and hydrogen pressure were varied to observe each of their effects on the product distribution. The change in metal loading had a remarkable impact on the preferred reaction pathway and product selectivity, while a high temperature of 200 °C and hydrogen pressure of 50 bar was determined to be necessary to fully achieve HDO to cycloalkanes. Consequently, this study has provided useful information on the production of both monomeric and dimeric cycloalkanes and has contributed to the development of the bio-oil upgrading process.