Gas-phase Hydrodechlorination Research Articles

Synthesis of group VI carbides and nitrides: application in catalytic hydrodechlorination

Molybdenum and tungsten carbide (Mo2C, W2C) and nitride (Mo2N) were prepared from MoO3 and WO3 by temperature-programmed treatment with C2H6/H2 and N2/H2. We have examined the influence of synthesis procedure, applying single-step (direct carburisation) and two-step (nitridation-carburisation and partial reduction-carburisation) processes, on crystallographic phase and catalytic response in the gas phase hydrodechlorination (HDC) of 1,3-dichlorobenzene (1,3-DCB). Single-step carburisation generated (hexagonal close-packed) hcp-Mo2C and hcp-W2C. Two-step nitridation–carburisation yielded (face-centred cubic) fcc-Mo2C via fcc-Mo2N in a topotactic transformation where surface area was increased (to 145 m2 g−1) at higher gas hourly space velocity (from 4800 to 96000 h−1) and decreasing heating rate (from 0.6 to 0.3 K min−1). Partial reduction of MoO3 prior to carburisation produced a composite (fcc + hcp)-Mo2C. Negligible ambient temperature H2 chemisorption (≤0.3 μmol g−1) was recorded for the synthesised (nitride and carbide) materials, but temperature-programmed desorption (TPD) resulted in significant H2 release (up to 67 μmol g−1 for (fcc + hcp)-Mo2C) that was generated during temperature-programmed reduction. Under the same reaction conditions, hcp- and fcc-carbides delivered equivalent specific HDC activity that was appreciably lower (by a factor of up to 20) than that obtained with fcc-Mo2N. The composite (fcc + hcp)-Mo2C exhibited the highest HDC rate that can be correlated with H2 released during TPD and which approached the performance of a benchmark Ni/SiO2 catalyst. HDC selectivity (to chlorobenzene) as a function of 1,3-DCB conversion coincided for all the nitride and carbide systems but deviated from Ni/SiO2, which favoured concerted HDC to benzene.

Unique selectivity in the hydrodechlorination of 2,4-dichlorophenol over hematite-supported Au

The gas-phase hydrodechlorination of 2,4-dichlorophenol (at 423K) has been studied over Au/Fe2O3 prepared by deposition–precipitation. Support and catalyst were characterised by TPR, XRD, H2 chemisorption/TPD, BET area/porosity and TEM/SEM measurements. Fe2O3 was reduced to Fe3O4 and Fe following TPR to 673K and 1273K, respectively; inclusion of Au lowered (by 200K) support reduction temperature. TPR of Au/Fe2O3 to 423K generated quasi-spherical Au particles (mean size=2.6nm) that promoted hydrogenolysis of ortho-Cl, generating 4-chlorophenol via a stepwise mechanism. We attribute this unprecedented selectivity to reactant interaction through –OH at electron-deficient Au sites, rendering ortho-Cl susceptible to attack. Solvent effects are demonstrated for a range of carriers where conversion of aqueous 2,4-DCP delivered the highest rate (1×10−3molClh−1mAu-2), equivalent to that achieved with Ni/SiO2 at 573K. Selectivity in the cleavage of sterically constrained Cl in mono-, di- and tri-chlorophenols is also demonstrated.

Comparison of different precious metals in activated carbon-supported catalysts for the gas-phase hydrodechlorination of chloromethanes

Four precious metals supported on activated carbon are compared as catalysts in the gas-phase hydrodechlorination (HDC) of chloromethanes. The intrinsic activity or turnover frequency (TOF) of the catalysts follows the order Pd/C>Rh/C>Pt/C>Ru/C in the HDC of dichloromethane (DCM) while the sequence Pd/C>Pt/C>Rh/C>Ru/C was found for the HDC of chloroform (TCM). High selectivities to non-chlorinated products were obtained in all cases except for the HDC of TCM with Rh/C and Ru/C where the selectivity to DCM greatly depends on the operating conditions. A wider diversity of non-chlorinated hydrocarbons was obtained as reaction products with these two catalysts, especially in the HDC of TCM, favoring the formation of carbonaceous deposits which provoked a marked deactivation of the catalysts. In contrast, CH4 was the only non-chlorinated product obtained with the Pt/C catalysts which showed by far the highest stability. Different reaction pathways were found depending on the catalyst and the starting chloromethane. The different reactivity of the metals is explained in terms of their different electronic structure and the physicochemical properties of the catalysts.

Hydrodechlorination of chlorobenzene on Ni and Ni-Pd catalysts modified by heteropolycompounds of the Keggin type

Ni and Ni-Pd catalysts modified by heteropolycompounds (HPCs) of the Keggin type are shown to be active in the gas-phase hydrodechlorination of chlorobenzene. The dispersion of the metal and the degree of its interaction with the support are found to change upon the addition of HPCs. The activity of the modified catalysts changes depending on the HPCs’ composition, benzene and cyclohexane being present in the products of hydrodechlorination. The addition of Pd as a second active metal is found to change both the activity and selectivity of the produced catalysts (with benzene as the sole product).

Hydrodechlorination of dichloromethane with mono- and bimetallic Pd–Pt on sulfated and tungstated zirconia catalysts

Monometallic (Pt or Pd) and bimetallic (Pt–Pd) catalysts supported on zirconia promoted with sulfate (SZ) or tungsten oxide (WZ) were prepared and tested in the gas-phase hydrodechlorination of dichloromethane. The catalysts showed a high selectivity to non-chlorinated products (between 80% and 90% at 250°C) being methane the main reaction product. As a general trend, the WZ catalysts yielded significantly higher dichloromethane conversion than the SZ ones, yielding all the catalysts initial conversions higher than 80% at a reaction temperature of 250°C. However, the former showed a very poor stability regardless of the metallic active phase. On the other hand, the presence of palladium in the sulfated zirconia catalyst avoids deactivation as proved in long-term experiments (80-h time on stream). XPS and elemental analyses of the used catalysts suggest that adsorption of organochlorinated species is a cause of deactivation by blocking the active sites. In the monometallic SZ Pt catalyst, deactivation occurs also by poisoning of the Pt sites by the H2S resulting from sulfate reduction under the hydrogen-rich gas atmosphere. The metal particle size appears to be a critical point with regard to stability of the catalysts. The one with the highest dispersion showed the highest stability with no signs of deactivation after more than 80h on stream.

Gas-phase hydrodechlorination of trichloroethylene over Pd/NiMgAl mixed oxide catalysts

Hydrotalcite derived NiMgAl mixed oxide (NiHT) catalysts with different NiMgAl molar ratio were synthesized and tested in the selective gas-phase hydrodechlorination of trichloroethylene to ethylene. The mixed oxide was further promoted by Pd in order to obtain Pd/NiHT catalysts. The catalysts performances for hydrodechlorination of trichloroethylene depend on the Ni/Mg/Al molar ratio, reduction temperature, and method of noble metal incorporation. The main products obtained were ethylene, methane, ethane, chloroethylene and traces of dichloroethylene. The higher the Ni amount in the NiHT support was, the higher were the catalytic activity and ethylene selectivity. Introduction of Pd increases the catalytic activity. Application of higher reduction temperatures improved the selectivity towards ethylene formation due to an increase in the concentration of surface metallic Ni. A better Pd-Ni surface interaction was obtained by impregnation of Pd on a previously reduced (823K) NiHT catalyst, resulting in higher ethylene selectivity (80%). The higher selectivity was associated to metallic Ni promoted by a Pd-Ni alloy, which was detected by HRTEM.

Laser electrodispersion as a new chlorine-free method for the production of highly effective metal-containing supported catalysts

Laser electrodispersion (LED) of metals is a promising technique for the preparation of heterogeneous catalysts as an alternative to wet impregnation of supports with the corresponding salt solutions. The LED technique can be used to deposit highly active chloride- and nitrate-free metal nanoparticles onto carbon or oxide supports. We report preparation and properties of new Ni-, Pd-, and Au-containing alumina-supported catalysts with low metal loadings (10–3–10–4 % mass) and their comparison with the previously studied carbon (Sibunit) supported systems. The catalysts demonstrate high stability and extremely high specific catalytic activity (by 2–3 orders of magnitude higher than for traditional catalysts) in the gas-phase hydrodechlorination (HDC) of chlorobenzene (CB).

Nickel nanoparticles embedded in the framework of mesoporous TiO 2: Efficient and highly stable catalysts for hydrodechlorination of chlorobenzene

Mesoporous TiO 2-supported metallic Ni catalysts were prepared through a multicomponent assembly approach, where surfactant, titania, and nickel precursor were cooperatively assembled in a one-pot process. With the characterization of transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, N 2 physisorption, hydrogen temperature-programmed reduction, and hydrogen temperature-programmed desorption, the resultant Ni nanoparticles were identified to be homogenously embedded within the framework of TiO 2 ranging in size from 1 to 6 nm. The embedment of Ni within the framework of support resulted in larger interface between Ni and support and thus stronger Ni–TiO 2 interaction. During the gas-phase hydrodechlorination of chlorobenzene reaction, the as-prepared 0.23%-Ni/TiO 2-DS delivered turnover frequency up to 1.5 times greater than that associated with the reference Ni/TiO 2 catalyst prepared by conventional incipient-wetness impregnation method. Meanwhile, the as-prepared 0.23%-Ni/TiO 2-DS also exhibited much improved stability for a continuous reaction of 30 h than the reference catalyst. The remarkable enhancement of the catalytic performances was found to depend on the strong metal–support interaction.

Characterization and reactivity of Al2O3 supported Pd-Ni bimetallic catalysts for hydrodechlorination of chlorobenzene

A series of Al2O3 supported bimetallic Pd-Ni catalysts were prepared by deposition–precipitation method. The physico-chemical properties of the catalysts were evaluated by different characterization techniques such as temperature programmed reduction (TPR), temperature programmed desorption of H2 (TPD), X-ray photoelectron spectroscopy (XPS), Braunner–Emmet–Teller (BET) surface area and pulse CO chemisorption. The activities of bimetallic Pd-Ni/Al2O3 catalysts were evaluated for continuous fixed bed gas phase hydrodechlorination of chlorobenzene operating at 140°C under atmospheric pressure. The activity profiles demonstrate that an exceptional activity and stability of Pd-Ni/Al2O3 catalysts is accomplished by judicial variation of Ni composition with respect to Pd, which had arrived at Pd and Ni in 0.5:0.5 (wt%) ratio, while high Ni loaded Pd-Ni catalysts exhibit poorer stability. The high activity and stability of optimal catalyst is invoked due to formation of very active Pd-Ni interfaces embedded with Pdδ+ species, whereas lower stability resulted in high Ni loaded catalysts is due to aggregation of Ni component on topical Pd surface. The activity of mono and bimetallic catalysts are well correlate with the characterization results.

Density Functional Theory Analysis of Dichloromethane and Hydrogen Interaction with Pd Clusters: First Step to Simulate Catalytic Hydrodechlorination

A density functional theory (DFT) analysis has been conducted for the gas-phase hydrodechlorination (HDC) of dichloromethane (DCM) with palladium catalyst to achieve a better knowledge of the reaction mechanism involved in the HDC process, which constitutes an emerging technology for the treatment of organochlorinated contaminants. The computational study included the effect of size, oxidation state, and spin configuration of Pd cluster on the adsorption of H2 and DCM reactants on the catalyst surface. Calculations described the activation of H2 by Pd clusters through a dissociative adsorption with low enthalpy values. In addition, partially and fully dissociated DCM intermediates on Pd surface were predicted by DFT calculations. Remarkably, the dissociative adsorption of DCM on Pd active sites occurs via the scission of C–Cl bonds, promoted by the formation of C–Pd linkages, implying high adsorption enthalpy. The computational results showed that DCM can be also molecularly adsorbed on both zerovalent and electrodeficient Pd species. However, the nondissociative adsorption of DCM over electrodeficient Pd cluster is remarkably favored in energy, with adsorption enthalpies (∼−50 kcal/mol) corresponding to chemisorption. Current theoretical evidence explained the deactivation of Pd/AC catalyst as a consequence of the selective poisoning of electrodeficient Pd active centers by chlorinated hydrocarbons, in good agreement with our previous experimental findings.

Hydrodechlorination of chloromethanes with a highly stable Pt on activated carbon catalyst

A platinum catalyst with activated carbon-support (Pt/C) was prepared and showed a high activity for the deep gas-phase hydrodechlorination (HDC) of dichloromethane (DCM) and chloroform (TCM), with conversions of up to 70% and 100%, respectively (operating conditions: atmospheric pressure, reaction temperatures of 150–250 °C, and space–times of 0.08–1.7 kg h mol −1). The catalyst was highly selective to methane (the only non-chlorinated product) with selectivities of up to 85% for HDC of DCM and 93% for HDC of TCM. The catalyst showed exceptional stability with no loss of activity after 26 days on stream in the HDC of DCM. This can be ascribed to its high resistance to poisoning by organic compounds compared to Pd/C catalysts previously studied. This can be attributed to re-dispersion of Pt during the reaction and to the high proportion of metal in the zero-valent state (Pt 0) which disfavors the stabilization of chlorocarbon compounds at the active centers of the catalyst.

Gas-phase hydrodechlorination of dichloromethane with activated carbon-supported metallic catalysts

The deep gas-phase hydrodechlorination (HDC) of dichloromethane (DCM) was studied over several laboratory-made activated carbon-supported metallic catalysts (Pd/C, Pt/C, Ru/C and Rh/C) at atmospheric pressure, reaction temperatures in the 200–250 °C range and space-times of 0.08 and 1.7 kg h mol −1. All the catalysts showed a high activity in HDC of DCM, with conversions in the range 89–99% at the highest temperature and space-time investigated, following the order Rh > Pd > Ru > Pt. Selectivities to non-chlorinated products up to 95% were reached. Methane was the main reaction product in all cases. Hydrodechlorination of DCM with Pt/C catalyst exclusively yielded methane and monochloromethane while hydrocarbons of more than one carbon atom were obtained with the other catalysts. The Pt/C catalyst was highly stable with no loss of activity after 65 h of time on stream at the testing conditions. The deactivation was more pronounced in the case of Ru (DCM conversion decreased a 40% after 20 h of operation), followed by Pd and in a less extent Rh with conversion decreases of 40 and 9%, respectively, after 65 h on stream. The fresh and used catalysts were characterized by N 2 adsorption–desorption, ICP-MS, TPR, XRD, XPS and H 2 and CO chemisorptions. Characterization results suggest that deactivation is mainly related to a decrease of the exposed metallic surface area along the reaction, which appears to be due to poisoning of active centers with chlorinated hydrocarbons, and in the case of Ru/C catalyst also metal sintering.

Hydrodechlorination of dichloromethane with a Pd/AC catalyst: Reaction pathway and kinetics

The kinetics of gas-phase hydrodechlorination (HDC) of dichloromethane (DCM) with a Pd on activated carbon commercial catalyst has been studied in a fixed bed reactor within the 200–350°C temperature range. Different kinetic equations have been checked for describing the evolution of DCM. Statistical and physical reliable parameters were found for a Langmuir–Hinshelwood type expression with DCM adsorption as the controlling step. The reaction pathway and the kinetic model have been elucidated from the evolution of dichloromethane and the identified reaction products (methane, monochloromethane, ethane and ethylene). Adsorbed CH2Cl* radical, CH2** and C2H4** carbene species are proposed as the three intermediates evolving to the final reaction products. An apparent activation energy of 23.9±2.3kJmol−1 has been obtained for dichloromethane disappearance.

Hydrodechlorination of chloromethanes with Pd on activated carbon catalysts for the treatment of residual gas streams

Laboratory-prepared Pd/C catalysts have been investigated in the deep gas-phase hydrodechlorination (HDC) of monochloromethane (CH3Cl), dichloromethane (CH2Cl2) and trichloromethane (CHCl3). The catalysts were found to be active in HDC, the reactivity following the order CHCl3>CH2Cl2>CH3Cl. Selectivities to non-chlorinated compounds were found to be higher than 90% in most cases. The results obtained with the catalyst prepared from PdCl2 suggest that all the reaction products are primary products. The CH4, CH3Cl and CH2Cl2 come from the hydrogenation of the corresponding adsorbed chloride radical, while hydrocarbons of more than one carbon atoms are formed by reaction and subsequent hydrodechlorination of two radicals adsorbed in neighbouring active centers. The catalyst undergoes a significant deactivation which appears to be due to the poisoning of active centers with chlorinated hydrocarbons. The use of Pd(NO3)2 as Pd precursor leads to a decrease in the activity due to its lower Pd dispersion and a lower proportion of electrodeficient Pd species.

Catalytic hydrodechlorination at low hydrogen partial pressures: Activity and selectivity response

Abstract The gas phase hydrodechlorination (HDC) of chlorobenzene (CB) and 1,3-dichlorobenzene (DCB) (373 K ≤ T ≤ 423 K, Ptotal = 1 atm) was performed over Pd/SiO2 (1.4–8.3%, w/w Pd) where the hydrogen partial pressure ( P H 2 ) was varied from 0.046 to 0.925 atm. The catalysts have been characterized in terms of BET area, temperature programmed reduction (TPR), hydrogen chemisorption/temperature programmed desorption (TPD) and TEM analyses. The HDC response to changes in contact time, chloroarene feed linear velocity and catalyst particle size were evaluated to establish reaction conditions wherein transport constraints were minimized, i.e. contact time = 2.33 s, feed rate = 0.014 molCl h−1 and particle size = 45–75 μm. HDC selectivity was found to be influenced by transport constraints, which resulted in a preferential partial HDC of 1,3-DCB. Under conditions of chemical control, larger Pd particles (mean values in the range 3–9 nm) delivered higher specific HDC rates. The dependence of HDC rate on P H 2 can be accounted for in terms of a Langmuir–Hinshelwood type model involving dissociative adsorption of H2 and associative adsorption of chloroarene with competition for surface sites. Applicability of this Model is demonstrated in terms of the χ2 (chi-square) test where the kinetic Models were discriminated on the basis of the standard F-test (% confidence). A dependence of HDC selectivity on P H 2 is demonstrated where the conversion of 1,3-DCB at a molar H2/DCB inlet ≤ 1.25 ( P H 2 ≤ 0.092 atm ) resulted in a higher selectivity to benzene as a result of a lesser competition for surface sites.

Hydrodechlorination of chlorobenzene over NiB/SiO 2 and NiP/SiO 2 amorphous catalysts after being partially crystallized: A consideration of electronic and geometrical factors

The effect of electronic and geometrical factors on the performance of the crystallized Ni–B and Ni–P amorphous alloys in the gas-phase hydrodechlorination (HDC) was investigated by means of N 2 adsorption, inductively coupled plasma spectroscopy (ICP), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), energy-dispersion X-ray spectroscopy (EDS), hydrogen chemisorption, hydrogen temperature-programmed desorption (H 2-TPD), and the activity evaluation. Through the thermal treatment at 673 K in H 2 flow, SiO 2-supported Ni–B amorphous alloy was partially crystallized to metallic Ni, while SiO 2-supported Ni–P amorphous alloy was partially crystallized to metallic Ni and Ni 3P. The crystallized catalysts have smaller metallic crystallites than SiO 2-supported Ni, a reference catalyst prepared by the impregnation method. B and P make different effects on the electron density of nickel in the crystallized samples. It is suggested that the electronic property of Ni strongly affects the catalyst activity, and the electron deficiency of nickel is favorable to promoting the hydrodechlorination of chlorobenzene. Turnover frequency (TOF) of the hydrodechlorination is related to the electronic and geometrical properties of the catalysts.

High catalytic activity and stability of palladium nanoparticles prepared by the laser electrodispersion method in chlorobenzene hydrodechlorination

Palladium nanoparticles deposited on thermally oxidized silicon and on the carbon support Sibunit by the laser electrodispersion method are extremely active in the gas-phase hydrodechlorination of chlorobenzene at 100–200°C. High conversion of chlorobenzene (above 90%) has been achieved with catalysts with an unusually low metal content (from 10−4 to 10−3 wt %). The cyclohexane-to-benzene ratio in the reaction products depends on the process duration, palladium content, and support nature. According to X-ray photoelectron spectroscopy (XPS) data, palladium in the catalysts retains its metallic state over a long time under the reaction conditions. Possible causes of the high catalytic activity (105 mol (mol Pd)−1 h−1) of the palladium nanoparticles and their stability to chlorination are discussed.

Novel one step preparation of silica supported Pd/Sr and Pd/Ba catalysts via an organometallic precursor: Application in hydrodechlorination and hydrogenation

A gas phase hydrodechlorination (HDC) of chlorobenzene (CB) and 1,2-dichlorobenzene (1,2-DCB) has been examined over Pd/SiO 2 (prepared by impregnation with Pd(C 2H 3O 2) 2) and two alkaline earth metal (AEM = Sr and Ba) promoted Pd/SiO 2 catalysts prepared from the organometallic precursor {(DMF) x AEMPd(CN) 4} ∞ (AEM = Sr, Ba; x = 4, 3). While Sr/SiO 2 or Ba/SiO 2 exhibited no measurable HDC activity, the bimetallic catalysts delivered specific HDC rates (per Pd metal surface area) that were up to a factor of 20 times higher than that recorded for Pd/SiO 2. The initial fractional dechlorination recorded for Sr–Pd/SiO 2 and Ba–Pd/SiO 2 was up to two orders of magnitude greater than that for Pd/SiO 2. We associate this promotional effect with a surface Pd/AEM synergy that enhances Pd dispersion with a resultant increase in H 2 chemisorption capacity allied to a more effective C–Cl bond activation for hydrogen scission. Bulk and surface catalyst characteristics, pre-and post-reaction, have been probed by IR, BET, TPR, H 2 chemisorption/TPD, XRD, XPS and TEM-EDX analyses. While 1,2-DCB conversion over Pd/SiO 2 was lower than that observed for CB due to inhibitory inductive and steric effects, CB and DCB reactivity were comparable over AEM-Pd/SiO 2. Each catalyst exhibited a temporal decline in HDC performance that we link to deleterious Cl interactions which impact H 2 uptake/release capacity. Although the bimetallic catalysts were less susceptible to deactivation, the samples post-HDC retain an appreciable Cl content with a redispersion of both AEM and Pd components and a disruption to the surface electronic characteristics that is apparent from the XPS profiles. The presence of AEM had no effect on benzene hydrogenation performance over freshly activated samples but post-HDC, Pd/SiO 2 exhibited depleted hydrogenation activity whereas both bimetallics (notably Sr–Pd/SiO 2) generated a significantly enhanced hydrogenation response that we ascribe to a surface restructuring that is beneficial for aromatic reduction.

Influence of particle size and nature of Pd species on the hydrodechlorination of chloroaromatics: Studies on Pd/TiO 2 catalysts in chlorobenzene conversion

TiO 2 supported Pd catalysts were synthesized by two different preparation methods namely conventional impregnation (IMP) and deposition-precipitation methods (DP) using two precursor salts Pd(NO 3) 2 and PdCl 2. The catalysts were characterized by various techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), temperature programmed reduction (TPR), CO chemisorption and BET surface area. The catalysts were evaluated for the gas phase hydrodechlorination (HDC) of chlorobenzene (CB) operating at atmospheric pressure. The catalyst prepared by deposition-precipitation using the chloride precursor (DP-Cl) exhibited higher dispersion and different electronic properties compared to the other catalysts. It also exhibited exceptional hydrodechlorination activity and stability. The generation of active electron deficient Pd species (Pd n+ ) on the catalyst surface appears to be the main reason for this behavior.

Gas-phase Hydrodechlorination of Chlorobenzene Over Silica-supported Ni2P Catalysts Prepared Under Different Reduction Conditions

The influence of reduction conditions on the properties and reactivity of silica-supported nickel phosphide (Ni2P/SiO2) catalysts for gas-phase hydrodechlorination (HDC) of chlorobenzene was investigated. The catalysts prepared under different reduction conditions had the similar specific surface area (∼370 m2 g-1), and pore diameter (∼5.2 nm) and Ni2P crystallites size (10–13 nm). However, comparing with Ni2P/SiO2 catalyst prepared at 923 K with the H2 space velocity of 15,000 mL g−1 h−1 for 2 h, with increasing the H2 space velocity from 15,000 to 19,200 mL g−1 h−1, or the reduction temperature from 923 to 1023 K or the reduction time from 2 to 6 h, the Ni/P ratio in the prepared catalyst was increased from 1/0.56 to about 1/0.50, and the HDC reaction induction period over the catalyst was also shortened from above 30 to 2–4 h. It is suggested that the induction period might be due to the blocking of active sites by excess phosphorus, which results in hindering the activation of chlorobenzene and the adsorption of hydrogen species on Ni2P. Under the conditions of 573 K and WNi/FCl = 186.6 gNi\({\text{mol}}{}_{{\text{Cl}}}^{ - 1} \) min, the chlorobenzene conversion over the Ni2P/SiO2 catalyst reached 99%, and it did not change during 36 h. The good activity and stability of the Ni2P/SiO2 catalyst was ascribed to the weak interaction between chlorine and Ni2P and a great of spilt-over hydrogen species on the catalyst surface.