Selectivity Of Cyclohexanol Research Articles

In situ activated CoAg bimetallic catalyst for selective hydrodeoxygenation of syringol to cyclohexanol

Development of highly effective catalysts for selective hydrodeoxygenation (HDO) of syringol, a model compound of lignin, to cyclohexanol (CYHAOL) is a challenge due to the intricate molecular structure of syringol. Herein, we have synthesized an in–situ activated cobalt–silver bimetallic catalyst, CoAg/SiO2, through a simple incipient–wetness impregnation method. The catalyst without pre–reduction treatment attained a complete conversion with 93.8 mol% CYHAOL selectivity under moderate reaction conditions. Characterizations including HRTEM, XPS, XRD, NH3–TPD, and H2–TPR unanimously revealed the structure–activity relationship of the catalyst. In the reaction system, Ag promoted the in–situ reduction of Co3O4 to form a polycrystalline–structure complex (CoOx) containing oxygen vacancies. Ag also combines with Co to construct strong acid sites. The synergy of CoOx, oxygen vacancies, Ag, and acid sites demonstrates a high–efficiency HDO of syringol to CYHAOL. CoAg/SiO2 exonerates the pre–reduction treatment, simplifying the preparation and maintenance process and preventing severe sintering of the metals.

The catalytic activity of copper/nickel supported on mesoporous aluminum catalyst towards cyclohexene epoxidation in continuous reactor

The intent of the study is to attain a high selectivity rate and stable interaction between metals in any heterogeneous catalyst. Cyclohexene is extremely valuable in industrial domains such as the synthesis of perfumes and nylons, and the mesoporous alumina was upstretched with a various ratio of bimetal copper (10%) and nickel (5%, 10%, 15%, and 20%) under wet impregnation procedures by the mesoporous aluminum catalyst. This impregnation of a metal and catalyst was used to assess the highest conversion and selectivity of cyclohexene to cyclohexanol. This catalytic nature was validated by analyzing the crystal structure and size using the X-ray diffraction technique. The functional group is identified using FT-IR (Fourier Transform Infrared Spectroscopy), while the surface area is assessed using BET (Brunauer-Emmet-Teller). HR-TEM (transmission electron microscopy) is used to validate the morphology of catalysts and their surface layers; HR-SEM (Scanning Electron Microscopy) is used to highlight and assess microparticles; and NH3TPD (Temperature-Programmed Desorption) is used to measure the overall acidity of the catalyst. The catalytic performance was proved by the yield achieved by varying parameters such as temperature, pressure, WHSV−1, reaction time, and solvents, which yielded over 98.5% in both cyclohexene conversion and selectivity. In the conversion of the product, H2O2 performs as an oxidant, and acetonitrile serves as a solvent at constant mild conditions of 90 °C and 20 bar pressure. Furthermore, even after seven successive runs with the Al2O3/Cu (10%)-Ni (15%) mixture, remarkable reusability was attained despite a minor decline in cyclohexanol selectivity. The effective impregnation of copper and nickel into supported mesoporous Al2O3 produced a long-lasting, stable hybrid nanostructure with excellent stability and no metal leaching. The current synthesis protocol's advantages and qualities include its efficiency, cost-effectiveness, ecological sustainability, and comfort of synthesis with readily available components.

Fine-Tuning of Ni/NiO over H-NbOx for Enhanced Eugenol Hydrogenation through Enhanced Oxygen Vacancies and Synergistic Participation of Active Sites.

The hydrogenation of lignin-derived phenolics to produce valuable chemicals is a promising but challenging task. This study successfully demonstrates the use of sustainable transition metal-based catalysts to hydrogenate lignin-derived phenolics. A defect-induced oxygen vacancy containing H-NbOx prepared from commercial Nb2O5 was employed as a catalyst. H-NbOx exhibited higher oxygen vacancies (158.21 μmol/g) than commercial Nb2O5 (39.01 μmol/g), evaluated from O2-TPD. Upon supporting 10 wt % Ni, a Ni/NiO interface was formed over H-NbOx, which was intrinsically active for the hydrogenation of phenolics. 10Ni/H-NbOx exhibited a two-fold increase in activity than 10Ni/Nb2O5, achieving >99% eugenol conversion and affording ∼94% 4-propyl cyclohexanol selectivity, wherein ∼63% eugenol conversion and ∼73% 4-propyl cyclohexanol selectivity were obtained over 10Ni/Nb2O5. The Ni/NiO formation was confirmed by X-ray photoelectron spectroscopy, HR-TEM, and H2-TPR analysis, while the oxygen vacancies were verified by Raman spectroscopy and O2-TPD analysis. The resulting interface enhanced the synergy between Ni and H-NbOx and facilitated hydrogen dissociation, confirmed by H2-TPD. Remarkably, 10Ni/H-NbOx maintained its catalytic activity for five tested cycles and demonstrated exceptional activity with various phenolics. Our findings highlight the potential of a sustainable transition metal catalyst for the hydrogenation of lignin-derived phenolic compounds, which could pave the path to producing valuable chemicals in an environmentally friendly manner.

Selective hydrodeoxygenation of monophenolics from lignin bio-oil for preparing cyclohexanol and its derivatives over Ni-Co/Al2O3-MgO catalyst

It is of significance to efficiently convert renewable and sustainable lignin bio-oil into cyclohexanol and its derivatives by selective hydrodeoxygenation to alleviate excessive dependence on fossil resources. However, the complicated components of lignin bio-oil hindered its application as bulk chemicals. A bimetallic Ni-Co catalyst supported on MgO-modified γ-Al2O3 was constructed for the catalytic hydrodeoxygenation of monophenolics from lignin bio-oil. The bimetallic catalyst with adding Co increased active centers and acid sites, improving the catalytic activity to the hydrodeoxygenation, compared to the Ni-based catalyst. The proper addition of MgO into the catalyst carrier increased the interplay among the Ni, Co particles and the catalyst carrier owing to the electron transfer from MgO into Ni and Co species. The enhanced interplay between active metal particles and the catalyst carrier benefited the dispersion of Ni, Co particles, and the average Ni and Co particle size decreased from 14 nm to 10 nm. Furthermore, MgO increased the basic sites, which effectively inhibited the elimination of the hydroxyl groups in phenols and preserved hydroxyl groups, resulting in a significant improvement in the selectivity of cyclohexanol and its derivatives. Ni-Co/Al2O3-MgO with good cycling stability contributed to a 65.6 wt% yield of cyclohexanol and its derivatives when the hydrodeoxygenation of monophenolics (such as guaiacol, 2,6-dimethoxyphenol and their alkyl substitutes) was pursued in isopropanol at 300 ℃ and 2 MPa H2 for 5 h. It was found that excessive dosage of the catalyst, higher temperature and hydrogen pressure, as well as longer reaction time, caused the excessive hydrodeoxygenation of monophenolics and hence decreased the selectivity to cyclohexanol and its derivatives. This work might provide a new idea for the high-value utilization of lignin bio-oil.

The influence of carbon supports and their surface modification on aqueous phase highly selective hydrogenation of phenol to cyclohexanol over different Ni/carbon catalysts

Cyclohexanol is an important feedstock in the chemical industry. Highly selective hydrogenation of phenols to cyclohexanol over non-noble metal catalysts remains a challenge. Herein, four distinctive carbon materials, carbon black (CB), activated carbon (AC), activated carbon fiber (ACF) and carbon nanotube (CNT) were selected as catalyst supports to load Ni nanoparticles for effective phenol hydrogenation. The results show that the phenol conversion and cyclohexanol selectivity in aqueous phase hydrogenation reaction at 180 °C for 2 h over 10 wt% Ni/AC catalyst could reach 99.7% and 94.8%, respectively. These values are better than those obtained over 10 wt% Ni/ACF, Ni/CNT and Ni/Al2O3. After surface modification of carbon supports, the catalytic activity and reuse effect of modified catalysts are significantly enhanced and the optimal temperature decreases to 150 °C. This is because that modified carbon supports have abundant surface functional groups so as to provide a high dispersion and stable anchor of ultrafine active Ni nanoparticles (∼12 nm). Phenol hydrogenation catalyzed by different Ni/carbon catalysts conforms to a first-order reaction, and their apparent activation energies are in a range of 49∼68 kJ mol−1 (49 corresponds to the modified catalyst Ni/MAC), which are markedly lower than that of Ni/Al2O3 (∼96 kJ mol−1). The potential mechanism of highly selective hydrogenation of phenol to cyclohexanol in this work is mainly controlled by the reaction kinetics, which is closely related to the different desorption abilities of cyclohexanone and cyclohexanol from the catalysts.

Selective hydrodeoxygenation of guaiacol to cyclohexanol over core-shell Cox@C@Ni catalysts under mild condition

Guaiacol, a typical lignin-derived phenolic compound, can be converted to high value-added cyclohexanol through hydrodeoxygenation (HDO). In this work, a series of core-shell Cox@C@Ni catalysts were prepared via two-step hydrothermal and calcination treatments, and applied to catalyze guaiacol to cyclohexanol. Compared with Co@C catalyst, core-shell Cox@C@Ni catalysts exhibited much better catalytic performance. Almost 100% guaiacol conversion and 90% cyclohexanol selectivity were achieved over Co1.2@C@Ni catalyst at 220 °C, 0 MPa N2 for 2 h using isopropanol as H-donor solvent, which was carried out under much milder conditions compared with previous research. The structure feature of core-shell Cox@C@Ni catalysts were analyzed by BET, XRD, SEM, TEM, HRTEM, etc. The catalyst compositions and acidities played a significant role on hydrodeoxygenation of guaiacol via ICP and NH3-TPD analysis. The influences of reaction temperature, reaction time and initial nitrogen pressure were also investigated to explore the optimal reaction condition. Moreover, the possible reaction pathways and reaction mechanism was deduced based on the product distributions and physicochemical properties.

Selective catalytic hydroconversion of crude phenols to cyclohexanols over a carbon-based nickel catalyst and separation of condensed arenes from a low-temperature coal tar

The dynamic combined strategy consisting of extraction, column chromatography, and catalytic hydroconversion (CHC) was used to prepare cyclohexanol (CH) from crude phenols (CPs) derived from a low temperature coal tar (LTCT) and enrich condensed arenes from the dephenolized fraction. Fluoranthene, anthracene, and pyrene with purities of 92.2, 91.7, and 95.5 %, respectively, were enriched by a combination of extraction and gradient elution in medium pressure preparative liquid chromatograph (MPPLCI) and high pressure preparative liquid chromatograph. CPs obtained by extracting LTCT were catalytically hydroconverted over a nickel supported on a nitrogen-doped carbon material (NDCM) prepared with a nickel-organic framework as the precursor. The mechanism for the CHC of CPs was explored using phenol as the model compound. The results show that phenol was completely converted and the selectivity of CH is up to 99.9 % in n-hexane under initial hydrogen pressure of 3 MPa at 160 °C for 1 h. The characterization of Ni/NDCM and the distribution of the products from the CHC of phenol indicate that Ni/NDCM can strongly adsorb phenol and effectively activate H2 to H···H, which transfer plays a crucial role in hydrogenating the aromatic rings.

Selective hydrodeoxygenation of guaiacol to cyclohexanol over NixCoyAlz catalysts under mild conditions

Hydrodeoxygenation is one of the key steps to upgrade of biomass derived bio-oil into valuable biofuels and chemicals. Developing of highly reactive and cost-effective catalysts for bio-oil hydrodeoxygenation is highly desired. Layered NixCoyAlz catalyst was prepared using layered double hydroxide (LDH) as the precursors. The optimized Ni1Co3Al2-600 catalyst exhibits excellent catalytic performance for guaiacol hydrodeoxygenation. Guaiacol could completely converted with 90.0% of cyclohexanol selectivity under relatively mild reaction conditions. The XRD and HRTEM characterizations of the as prepared catalysts confirmed the formation of Ni-Co alloy and the XPS analysis revealed the strong interaction between Al species with both Ni and Co in catalyst Ni1Co3Al2-600, which should contribute to its high catalytic activity for guaiacol hydrodeoxygenation. Catalyst Ni1Co3Al2-600 also demonstrated excellent versatility for the hydrodeoxygenation reactions of guaiacyl and syringyl compounds as well as high stability. The results from this work could provide a new approach for the constructing of effective catalysts from non-noble metal LDHs.

Selective hydrodeoxygenation of lignin-derived phenols to alkyl cyclohexanols over highly dispersed RuFe bimetallic catalysts

Selective hydrodeoxygenation (HDO) of phenolic compounds derived from the pyrolysis lignin-oil to desired products is a promising route in the high-value utilization of biomass-derived products. Cyclohexanol, as one of the important chemical materials, is an intermediate of catalytic HDO of guaiacol. Controllable selective HDO is conducted to improve the cyclohexanol selectivity over RuFe bimetallic catalyst prepared by ethylene glycol reduction method in this work. 99.99% guaiacol conversion and 81.35% cyclohexanol selectivity are obtained over optimized 2Ru2.5Fe/Al2O3-EG catalyst, which is better than those over 2Ru/Al2O3-EG catalyst. The mild catalyst preparation method gives it a high dispersion and uniform distribution of Ru and Fe species on the support. Various characterizations have proved that the intimate contact between Ru and Fe2O3 species contributes to the improvement of cyclohexanol selectivity. Partial blockage of Ru sites by Fe2O3 species slightly reduces the hydrogen adsorption capacity while the addition of Fe helps enhancing the hydrogenolysis of C-OMe bond. The reciprocal effect facilitates the removal of methoxyl groups and hinders the dehydroxylation of cyclohexanol to cyclohexane. Besides, other phenolic compounds and pyrolysis lignin-oil as substrates also show good selective HDO reactivity to corresponding alkyl cyclohexanols, implying potential application in the transformation from lignin-oil to high-value products.

The selective hydrodeoxygenation of guaiacol to cyclohexanol over cobalt-modified TS-1 catalysts

A Co-modified zeolite (Co/TS-1) catalyst is prepared and evaluated for the catalytic hydrodeoxygenation (HDO) of the lignin-derived model compound guaiacol under mild conditions at 1 MPa H2 and 200 °C. According to the systemic experimental investigations including reduction temperatures, metal loading and reaction time, it is found that the guaiacol conversion and cyclohexanol selectivity over guaiacol HDO are significantly improved by regulating the Ti content, Co content and reduction temperature, in which 5.0%Co/TS-1 (Si/Ti = 110) reduced in 600 °C shows the superior HDO performance with 94.3% guaiacol conversion and 88.7% cyclohexanol selectivity. Combined with XRD, TEM, BET, NH3-TPD, Py-IR, H2-TPR, UV–Vis and XPS characterizations, it is confirmed that the introduction of appropriate Ti could modulate the catalyst Lewis acid sites and the interaction between Co and support to affect the metal reduction degree, to realize the improvement of the substrate adsorption and exposing more metallic Co0 active sites, resulting in higher HDO performance. In addition, the reaction pathway of guaiacol HDO to cyclohexanol over Co/TS-1 is proposed via demethoxylation of guaiacol to generate reaction intermediate phenol.

Selective catalytic hydroconversion of a low-temperature coal tar-derived crude phenols to cyclohexanol over a nitrogen-doped Co-based catalyst

An extraction-catalytic hydroconversion (CHC)-column chromatography strategy was designed for the CHC of crude phenols to obtain cyclohexanol (CH) and enrich non-substituted condensed arenes (NSCAs) from a low-temperature coal tar (LTCT). Phenanthrene, fluoranthene, and pyrene were enriched with purities of 94.3%, 90.1%, and 96.1%, respectively, by extraction with petroleum ether and methanol and subsequent gradient elution using a medium pressure preparative liquid chromatograph (MPPLC) and high pressure preparative liquid chromatograph. Co supported on a nitrogen-doped carbon material (NDCM) was prepared by one-step pyrolysis of a cobalt-organic framework under N2 atmosphere and crude phenols (CPs) were extracted from the LTCT. CH with a purity of 98.7% was obtained by catalytically hydroconverting CPs over Co/NDCM and subsequent elution using the MPPLC. The mechanism for the CHC of CPs over Co/NDCM was examined using phenol as the LTCT-related model compound. As a result, phenol was completely converted and the CH selectivity reached 97.7% in n-hexane under initial hydrogen pressure of 3 MPa at 140 °C for 3 h. The characterization of Co/NDCM and the distribution of products from the CHC of phenol indicate that Co/NDCM can activate H2 to H···H and the H···H transfer plays a crucial role in hydrogenating aromatic rings.

Electrocatalytic hydrogenation of phenol by active sites on Pt-decorated shrimp shell biochar catalysts: Performance and internal mechanism

The development of highly-active electrocatalysts and identification of active sites contribution are necessary for electrocatalytic hydrogenation (ECH) of bio-oil. Herein, the Pt-decorated shrimp shell biochar (SSB) catalysts with high nitrogen content was prepared successfully. The biochar-based catalysts were first used for the ECH of bio-oil model compounds. Results showed that the Pt/SSB catalysts exhibited excellent electrocatalytic activity and stability, realizing 100 % conversion of phenol and 98 % total selectivity of cyclohexanone and cyclohexanol within 5 h. By correlation analysis and density functional theory (DFT) calculations, the Pt, Pt-Nx, and CO sites in Pt/SSB catalysts were found to play an important role in the stepwise hydrogenation of phenol. Furthermore, the Pt-Nx sites were identified as the main contributor to the high selectivity of cyclohexanol generation. This study lays the foundation for the controllable preparation of electrocatalysts with high activity and stability, which is significant for large-scale upgrading of bio-oil in the future.

Superhydrophobic Ru Catalyst for Highly Efficient Hydrogenation of Phenol under Mild Aqueous Conditions

Selective hydrogenations of lignin-derived phenolic compounds represent essential processes in the chemical industry, especially for production of a multitude of fine chemicals. However, selective hydrogenation of phenolic compounds in water phase suffers from low conversion. Here we report a catalyst of well-dispersed Ru clusters fixed in N-doped mesoporous hollow carbon spheres (Ru@N-CS) for enhanced cyclohexanol productivity in phenol hydrogenation at mild aqueous condition. This superhydrophobicity carbon spheres appear to selectively allow diffusion of phenol and hydrogen molecules to the electron-rich coordination unsaturated Ru active sites, while confining the reactants there to enhance its reaction probability. The Ru@N-CS catalyst can selectively hydrogenate phenol at 80 °C and 0.5 MPa of H2 in 30 min in aqueous medium with phenol conversions of 100% and ~100% cyclohexanol selectivity, corresponding to cyclohexanol productivity up to 471 per g of Ru per minute. The TOF value is up to 9980 h−1, which 14 times more than Ru nanoparticles supported on N-doped carbon hollow spheres (Ru/N-CS). This work provides an important catalytic system for upgrading of bio-oil into value-added chemicals under mild aqueous-phase.

Poly(ionic liquid)s hollow spheres nanoreactor for enhanced cyclohexane catalytic oxidation

Hollow structure nanoreactors take advantage of catalyst loading and enhanced activity by shell construction. In this work, functionalized poly(ionic liquid)s (PILs) with hollow spherical structures were synthesized by polymerization- and quaternization-based approaches. These hollow structure PILs (HPILs) could be controllable designed from IL monomer easily, giving HPILs various properties. In the subsequent selective oxidation of cyclohexane, the HPILs acting as nanoreactors could efficiently improve the activity of metal salt catalysts (CoCl2) and displayed adjustable selectivity for cyclohexanone, cyclohexanol (KA) or adipic acid (AA) by different types of HPILs. In kinetic study, it follows first-order reaction kinetics which CoCl2/HPIL-C12 had a lower the activation energy of 29.1 kJ/mol. Importantly, these nanoreactors storing the catalysts could be recovered and reused more than 7 times without significant loss of activity. A theoretical model for the hollow spherical reactor was further established to support the advance of the HPILs reactor, which could also help to predict reaction process in other core-shell catalytic system. Due to controlled substrate transfer and enhanced radical generation in HPILs, the reaction process could be adjusted to enhance the conversion of cyclohexane and selective oxidation to AA.

Hydrogenation of Lignin‐derived Phenolic Compounds over Ru/C Enhanced by Al2O3 Catalyst at Room Temperature

AbstractHydrogenation is a promising strategy for the lignin‐derived phenolic compounds to produce platform chemical compounds and high‐value biofuel precursors. In this study, an efficient hydrogenation of phenol over Ru/C enhanced by Al2O3 catalyst at room temperature was proposed, with phenol conversion and cyclohexanol selectivity both close to 100 %. The addition of Al2O3 can make a significant difference on the phenol adsorption by the introduction of abundant Lewis acid site, which enabled to activate aromatic rings by changing the electrophilic substitution reaction of aromatic groups and trigger the occurrence of phenol hydrogenation under the catalysis of Ru/C. The Lewis acid site and metal site cooperated with each other and promoted the conversion of phenol to cyclohexanol as the final products. Moreover, a variety of other phenolic or aromatic compounds were also tested. The steric effects derived from the different substituted groups on aromatic rings had a significant influence on the hydrogenation performances.

Preparation of cyclohexanol from lignin-based phenolic concoction using controlled hydrogen delivery tool over in-situ Ru catalyst

This work investigated hydrodeoxygenation-hydrogenation of lignin-based methoxyphenols (obtained through hydrothermal liquefaction (HTL) of lignin) to cyclohexanol in high yields over in situ generated Ru(0)@Mg(OH)2 catalyst in aqueous medium. The active catalyst Ru(0)@Mg(OH)2 is generated in situ from hydrous ruthenium oxide (HRO)/Mg(OH)2 under reaction conditions, as confirmed by various physiochemical techniques. Continuous and controlled addition of H2 at constant temperature facilitated in improving the selectivity of cyclohexanol compared to the conventional batch mode (pre-set pressure) process. Complete conversion of methoxyphenols with 93–99% selectivity for cyclohexanol was achieved at 10 mL/min H2 flow under comparatively milder reaction conditions. The adopted procedure and the in situ catalyst reported in this work is also effective for lignin-derived phenolic concoction.

Catalytic Hydrodeoxygenation of Guaiacol to Cyclohexanol over Bimetallic NiMo-MOF-Derived Catalysts

Lignin is an attractive renewable source of aromatics with a low effective hydrogen to carbon ratio (H/Ceff). The catalytic hydrodeoxygenation (HDO) of lignin-derived model compounds is a key strategy for lignin upgrading. In this work, the HDO of guaiacol, a typical lignin-derived compound, was carried out over metal–organic framework (MOF)-derived Ni-based catalysts. A monometallic Ni-MOF catalyst and different ratios of bimetallic NiMo-MOF catalysts were synthesized by a hydrothermal process, followed by a carbonization process. Among these catalysts, Ni3Mo1@C exhibited an excellent catalytic performance, affording a guaiacol conversion of 98.8% and a cyclohexanol selectivity of 66.8% at 240 °C and 2 MPa H2 for 4 h. The addition of Mo decreased the particle size of the spherical structure and improved the dispersion of metal particles. The synergistic effect between Ni and Mo was confirmed by various means, including ICP, XRD, SEM, TEM, and NH3-TPD analyses. In addition, the effect of the reaction temperature, time, and H2 pressure during the HDO process is discussed in detail.

Ultrafine PdRu Nanoparticles Immobilized in Metal–Organic Frameworks for Efficient Fluorophenol Hydrodefluorination under Mild Aqueous Conditions

Ultrafine PdRu Nanoparticles Immobilized in Metal–Organic Frameworks for Efficient Fluorophenol Hydrodefluorination under Mild Aqueous Conditions

Highly Selective Hydrogenation of Phenol Catalyzed by Porous BN Supported Ni−Pd Catalysts

AbstractPhenol, as a phenolic organic substance, is widely present in industrial wastewater and is an important organic pollutant. Porous boron nitride (p‐BN) is an ideal material as catalyst support because it has a large specific surface area and a variety of pore structures. In this paper, a series of Ni−Pd/p‐BN catalysts were prepared by precipitation method. Meanwhile, the catalytic performance of the catalysts for the hydrogenation of phenol to cyclohexanol was systematical and comprehensive studied. Significantly, with the optimal catalyst, the conversion of phenol was greatly improved to reach more than 99.9 %, and the selectivity of cyclohexanol could almost exceed 99.8 %. In addition, the Ni−Pd/p‐BN catalyst can be reused as an effective catalyst for numerous cycles, indicating superior reusability and recyclability. After five cycles, the conversion of phenol and the selectivity of cyclohexanol is only reduced to ∼80 %. This catalyst will be a promising material in the field of industrial catalysis applications.

Phenol hydrogenation to cyclohexanol on a novel Pd7P3/SiC catalyst with high activity and selectivity

Aqueous catalytic phenol has been explored using Pd7P3/SiC catalysts in the presence of H2. Palladium phosphide was prepared by oleoamine reduction and supported on silicon carbide. The physicochemical properties of the catalyst were characterized by inductively Coupled Plasma Emission Spectrometer (ICP-MS), X-ray diffractometer (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results show that palladium phosphide is successfully supported on silicon carbide, and the dispersion is relatively uniform with the particle size is about 6–9 nm. Under the same catalytic conditions, a catalyst with a loading of 2.4 wt% exhibits the best activity. When the temperature is 40 °C, the initial pressure is 5 bar, the conversion of phenol can reach more than 99%, and the selectivity of cyclohexanol reaches 94% after 2 h reaction.