A Pt/WO3/TiO2 catalyst for propane oxidation was prepared by a stepwise wet impregnation method, and was aged at 800°C for 5 hr. Compared to the sulfate-derived titania supported catalyst, the introduction of tun...A Pt/WO3/TiO2 catalyst for propane oxidation was prepared by a stepwise wet impregnation method, and was aged at 800°C for 5 hr. Compared to the sulfate-derived titania supported catalyst, the introduction of tungsten oxide as stable Br nsted acid sites led to the formation of more metallic platinum active sites at the Pt/WO3 interface. The dissociation of surface intermediates for propane oxidation was promoted on the WO3-modified catalyst. This, as well as the inhibition effects of tungsten oxide on the sintering of anatase and the phase transformation to rutile, resulting in a high activity and thermal stability for the Pt/WO3/TiO2 catalyst.展开更多
Abstract： In order to study the flammability and explosion property of gases during the propane oxidation to acrylic acid process, the explosion limits and the safety oxygen content of gases at the recycle gas compre...Abstract： In order to study the flammability and explosion property of gases during the propane oxidation to acrylic acid process, the explosion limits and the safety oxygen content of gases at the recycle gas compressor outlet, the reactor inlet, and the reactor outlet were theoretically calculated and experimentally tested. Finally, the inert limit was also determined. It showed that gases at the recycle gas compressor outlet and the reactor outlet were nonflammable based on three indicators： the explosion limits, the safety oxygen content and the inert limit. The C3H6 and O2 contents were higher at the reactor inlet, which made the mixed gases easily ignitable. However, the large amount of inert gases suppressed the possibility of explo- sion effectively. As a consequence, no explosion phenomenon would happen in all three locations. But gases at the reactor inlet are most dangerous, where more supervision on the concentration of gases and more strict control on the temperature and pressure should be implemented. Besides this, open flame, hot surfaces and other sources of ignition are prohibited in working spaces. The experimental results can be applied to similar process for oxidation of propane.展开更多
A series of nitrogen-doped CoAlO(N-CoAlO)were constructed by a hydrothermal route combined with a controllable NH_(3) treatment strategy.The effects of NH_(3) treatment on the physico-chemical properties and oxidation...A series of nitrogen-doped CoAlO(N-CoAlO)were constructed by a hydrothermal route combined with a controllable NH_(3) treatment strategy.The effects of NH_(3) treatment on the physico-chemical properties and oxidation activities of N-Co AlO catalysts were investigated.In comparison to CoAlO,a smallest content decrease in surface Co^(3+)(serving as active sites)while a largest increased amount of surface Co^(2+)(contributing to oxygen species)are obtained over N-Co AlO/4h among the N-CoAlO catalysts.Meanwhile,a maximum N doping is found over N-CoAlO/4h.As a result,N-CoAlO/4h(under NH_(3) treatment at 400℃ for 4 hr)with rich oxygen vacancies shows optimal catalytic activity,with a T90(the temperature required to reach a 90% conversion of propane)at 266℃.The more oxygen vacancies are caused by the co-operative effects of N doping and suitable reduction of Co^(3+) for NCoAlO/4h,leading to an enhanced oxygen mobility,which in turn promotes C_(3)H_(8) total oxidation activity dominated by Langmuir-Hinshelwood mechanism.Moreover,in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTs)analysis shows that N doping facilities the decomposition of intermediate species(propylene and formate)into CO_(2)over the catalyst surface of N-CoAlO/4h more easily.Our reported design in this work will provide a promising way to develop abundant oxygen vacancies of Co-based catalysts derived from hydrotalcites by a simple NH_(3) treatment.展开更多
Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile...Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile surface-engineering strategy wherein NiCo_(2)O_(4) was treated with different alkali solvents was developed.The obtained catalyst(NiCo_(2)O_(4)-OH)showed a higher surface alkalinity and more surface defects compared to the pristine spinel oxide,including enhanced structural distortion as well as promoted oxygen vacancies.The propane oxidation ability of NiCo_(2)O_(4)-OH was greatly enhanced,with a propane conversion rate that was approximately 6.4 times higher than that of pristine NiCo_(2)O_(4) at a reaction temperature 193℃.This work sets a valuable paradigm for the surface modulation of spinel oxide via alkali treatment to ensure a high-performance oxidation catalyst.展开更多
Directional design of efficient catalysts for volatile organic compounds degradation remains a complex,yet effective and challenging process.Herein,oxygen-rich vacancy Co_(3)O_(4)-anchored Pt catalysts were prepared t...Directional design of efficient catalysts for volatile organic compounds degradation remains a complex,yet effective and challenging process.Herein,oxygen-rich vacancy Co_(3)O_(4)-anchored Pt catalysts were prepared through atom-trapping strategy and relevant vacancy defect inductive effect was proposed.The 0.6Pt/VO-Co_(3)O_(4)catalyst presented a reaction rate value of 32.2×10^(-5)mol·g_(cat)^(-1)·s^(-1)at 160℃for catalytic propane total oxidation,which was nearly 5 times the reaction rate of Co_(3)O_(4)(6.7×10^(-5)mol·g_(cat)^(-1)·s^(-1)).Also,it exhibited excellent water-resistance and catalytic stability.The Pt atoms were stabilized on the Co_(3)O_(4)surface by vacancy defects to improve dispersion.Meanwhile,the vacancy defect inductive effect induced stronger electron interaction between Pt and Co_(3)O_(4)on the surface,thus promote the redox ability at low-temperature.The mobility and oxygen-activating ability of surface lattice oxygen were also strengthened by the vacancy defect inductive effect.This facilitated the generation of more surface-active oxygen species for the cleavage of C-H bond and the deep oxidation of intermediate species.Overall,this study proposed a novel concept the fabrication of highly efficient catalysts for the purpose of catalytic oxidation.展开更多
Ammonium salts, （NH4）6HPMo11MO40 （M = Ni, Co, Fe）, have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 ℃ and 420 ℃ after in-situ pre-treatment performed...Ammonium salts, （NH4）6HPMo11MO40 （M = Ni, Co, Fe）, have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9 ℃/min. They were characterized by BET method, XRD, 31p NMR, UV-Vis and IR techniques. The catalysts were found active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9 ℃/min.展开更多
The effects of metal atomic ratio, water content, oxygen content, and calcination temperature on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic aci...The effects of metal atomic ratio, water content, oxygen content, and calcination temperature on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid have been investigated and discussed. Among the catalysts studied, it was found that the MoVTeNbO catalyst calcined at a temperature of 600 ℃ showed the best performance in terms of propane conversion and selectivity for acrylic acid under an atmosphere of nitrogen. An effective MoVTeNbO oxide catalyst for propane selective oxidation to acrylic acid was obtained with a combination of a preferred metal atomic ratio （Mo1V0.31Te0.23Nb0.12）. The optimum reaction condition for the selective oxidation of propane was the molar ratio of C3H8 ：O2 ： H2O ： N2 = 4.4： 12.8 ： 15.3 ： 36.9. Under such conditions, the conversion of propane and the maximum yield of acrylic acid reached about 50% and 21%, respectively.展开更多
The effects of chemical composition and preparation conditions,especially calcination atmosphere and water content on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of p...The effects of chemical composition and preparation conditions,especially calcination atmosphere and water content on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid were investigated.Among the catalysts studied,Mo_(1.0)V_(0.3)Te_(0.23)Nb_(0.12)O_(x) catalyst calcined in inert atmosphere at 600℃shows the best performance in terms of propane conversion and selectivity to acrylic acid.The results reveal that proper chemical composition, calcination atmosphere and water content affect greatly the catalysts in many ways including structure,chemical composition,which are related to their catalytic performances;and 51.0%propane conversion and 30.5%one-pass yield to acrylic acid can be achieved at the same time.展开更多
Selective oxidation of propane by lattice oxygen of vanadium-phosphorus oxide(VPO) catalysts was investigated with a pulse reactor in which the oxidation of propane and there-oxidation of catalyst were implemented alt...Selective oxidation of propane by lattice oxygen of vanadium-phosphorus oxide(VPO) catalysts was investigated with a pulse reactor in which the oxidation of propane and there-oxidation of catalyst were implemented alternately in the presence of water vapor. The principalproducts are acrylic acid (AA), acetic acid (HAc), and carbon oxides. In addition, small amounts ofC_1 and C_2 hydrocarbons were also found, molar ratio of AA to HAc is 1.4-2.2. The active oxygenspecies are those adsorbed on catalyst surface firmly and/or bound to catalyst lattice, i.e. latticeoxygen; the selective oxidation of propane on VPO catalysts can be carried out in a circulatingfluidized bed (CFB) riser reactor. For propane oxidation over VPO catalysts, the effects of reactiontemperature in a pulse reactor were found almost the same as in a steady-state flow reactor. Thatis, as the reaction temperature increases, propane conversion and the amount of C_1+C_2 hydrocarbonsin the product increase steadily, while selectivity to acrylic acid and to acetic acid increaseprior to 350℃ then begin to drop at temperatures higher than 350℃, and yields of acrylic acid andof acetic acid attained maximum at about 400℃. The maximum yields of acrylic acid and of aceticacid for a single-pass are 7.50% and 4.59% respectively, with 38.2% propane conversion. When theamount of propane pulsed decreases or the amount of catalyst loaded increases, the conversionincreases but the selectivity decreases. Increasing the flow rate of carrier gases causes theconversion pass through a minimum but selectivity and yields pass through a maximum. In a fixed bedreactor, it is hard to obtain high selectivity at a high reaction conversion due to the furtherdegradation of acrylic acid and acetic acid even though propane was oxidized by the lattice oxygen.The catalytic performance can be improved in the presence of excess propane. Propylene can beoxidized by lattice oxygen of VPO catalyst at 250℃, nevertheless, selectivity to AA and to HAc areeven lower, much more acetic acid was produced (molar ratio of AA to HAc is 0.19:1-0.83:1) thoughthe oxidation products are the same as from propane.展开更多
Alkaline earth metal （Mg,Ca,Sr and Ba）-doped Mo-V-Sb-O x catalysts,prepared by a dry-up method,have been investigated for their catalytic performance in the oxidation of propane under different reaction conditions.T...Alkaline earth metal （Mg,Ca,Sr and Ba）-doped Mo-V-Sb-O x catalysts,prepared by a dry-up method,have been investigated for their catalytic performance in the oxidation of propane under different reaction conditions.The catalysts have been characterized by N2 adsorption-desorption,temperature-programmed desorption （TPD） of NH3,SEM and XRD.Influence of water vapor on the catalytic performance,particularly on the selectivities to acetic acid and acrylic acid,has also been studied.The selectivity to acrylic acid was improved significantly by the doping of alkaline earth metals to Mo-V-Sb-O x catalysts.The surface acidic sites of the catalyst decreased with the doping of the catalyst with alkaline earth metals,which ultimately was found to be beneficial for obtaining high selectivity to acrylic acid.The catalytic activity and product selectivities were found to be influenced by the reaction temperature,C3H8/O2 ratio and space velocity.A significant improvement in the selectivity to acrylic acid has also been observed by the addition of water vapor in the feed of propane and oxygen in the oxidation of propane.展开更多
Thermal stability has long been recognized as a major limitation for the application of ligand modification in high-temperature reactions. Herein, we demonstrate polymeric phosphate as an efficient and stable ligand t...Thermal stability has long been recognized as a major limitation for the application of ligand modification in high-temperature reactions. Herein, we demonstrate polymeric phosphate as an efficient and stable ligand to tune the selectivity of propane oxidative dehydrogenation. Beneficial from the weakened affinity of propene, NiO modified with polymeric phosphate shows a selectivity 2–3 times higher than NiO towards the production of propene. The success of this regulation verifies the feasibility of ligand modification in high-temperature gas-phase reactions and shines a light on its applications in other important industrial reactions.展开更多
In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane （ODHP）. The techniques of temperature-programmed red...In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane （ODHP）. The techniques of temperature-programmed reduction with H2 （H2-TPR）, N2 adsorption-desolption, Fourier transform infrared spectroscopy （FT-IR）, X-ray diffraction （XRD） and X-ray photoelectron spectra （XPS） were employed for catalyst characterization. It is found that the activity of the catalysts for ODHP increases first and then decreases with the increase of Mo content. The catalyst with a Mo/Ni atomic ratio of 1/1 exhibits the best catalytic activity, which gives the propene selectivity of 81.4% at a propane conversion of 11.3% under 600 ~C and maintains the good catalytic performance for 22 h on stream. This is related not only to its high reducibility and dispersion as revealed by TPR and XRD, but also to the formation of more selective oxygen species on the MoOz-NiO interface as identified by XPS.展开更多
An industrial scale propylene production via oxidative dehydrogenation of propane （ODHP） in multi-tubular re- actors was modeled. Multi-tubular fixed-bed reactor used for ODHP process, employing 10000 of small diame...An industrial scale propylene production via oxidative dehydrogenation of propane （ODHP） in multi-tubular re- actors was modeled. Multi-tubular fixed-bed reactor used for ODHP process, employing 10000 of small diameter tubes immersed in a shell through a proper coolant flows. Herein, a theory-based pseudo-homogeneous model to describe the operation of a fixed bed reactor for the ODHP to correspondence olefln over V2O5/γ-Al203 catalyst was presented. Steady state one dimensional model has been developed to identify the operation parameters and to describe the propane and oxygen conversions, gas process and coolant temperatures, as well as other pa- rameters affecting the reactor performance such as pressure. Furthermore, the applied model showed that a double-bed multitubular reactor with intermediate air injection scheme was superior to a single-bed design due to the increasing of propylene selectivity while operating under lower oxygen partial pressures resulting in propane conversion of about 37.3%. The optimized length of the reactor needed to reach 100% conversion of the oxygen was theoretically determined. For the single-bed reactor the optimized length of 11.96 m including 0.5 m of inert section at the entrance region and for the double-bed reactor design the optimized lengths of 5.72 m for the first and 7.32 m for the second reactor were calculated. Ultimately, the use of a distributed oxygen feed with limited number of injection points indicated a significant improvement on the reactor performance in terms of propane conversion and propylene selectivity. Besides, this concept could overcome the reactor run- away temperature problem and enabled operations at the wider range of conditions to obtain enhanced propyl- ene production in an industrial scale reactor.展开更多
PtSnNa/γ-Al2O3 catalyst is widely used in the dehydrogenation of light alkane. This paper reports a new fabrication method of the catalyst. In the work, γ-Al2O3, SnCl4 and NaCl were ball milled to upload Sn and Na＋...PtSnNa/γ-Al2O3 catalyst is widely used in the dehydrogenation of light alkane. This paper reports a new fabrication method of the catalyst. In the work, γ-Al2O3, SnCl4 and NaCl were ball milled to upload Sn and Na＋ onto the support instead of the conventionally used immersion method. The subsequent baking procedures frimly fixed Sn onto the support, which could disperse Pt introduced by immersion. The effects of Sn and Na＋ additives on the catalytic performance of PtSnNa/y-Al2O3 catalyst were investigated. It was found that the appropriate molar ratio of Sn/Pt was 6：1 while the favorable weight percentage of Na＋ was 0.90%. Compared with the reaction catalyzed by the industrially employed PtSnNa/ γ-Al2O3 catalyst, the conversion of propane and the selectivity of propylene had been greatly improved, which were 26.97%; and 99.18% respectivelv after 12 h reaction.展开更多
Oxidative dehydrogenation of propane is an attractive route for the synthesis of propylene due to its favorable thermodynamic and kinetic characteristics, however, it is challenging to realize high selectivity towards...Oxidative dehydrogenation of propane is an attractive route for the synthesis of propylene due to its favorable thermodynamic and kinetic characteristics, however, it is challenging to realize high selectivity towards propylene. Recently, it has been discovered that boron nitride (BN) is a promising catalyst that affords superior selectivity towards propylene in oxidative dehydrogenation of propane. Summarizing the progress and unravelling the reaction mechanism of BN in oxidative dehydrogenation of propane are of great significance for the rational design of efficient catalysts in the future. Herein, in this review, the underlying reaction mechanisms of oxidative dehydrogenation of propane over BN are extracted;the developed BN catalysts are classified into pristine BN, functionalized BN, supported BN and others, and the applications of each category of BN catalysts in oxidative dehydrogenation of propane are summarized;the challenges and opportunities on oxidative dehydrogenation of propane over BN are pointed out, aiming to inspire more studies and advance this research field.展开更多
Oxidative dehydrogenation of propane over V-Mg-O and MCl_n(M=Cu^+,Li^+, Ag^+,Cd^(2+))promoted V-Mg-O catalysts was studied.XRD result showed that the V-Mg-O catalysts were composed of MgO and Mg_3(VO_4)_2.The yield of...Oxidative dehydrogenation of propane over V-Mg-O and MCl_n(M=Cu^+,Li^+, Ag^+,Cd^(2+))promoted V-Mg-O catalysts was studied.XRD result showed that the V-Mg-O catalysts were composed of MgO and Mg_3(VO_4)_2.The yield of propene was much higher over CuCl and LiCl promoted VMgO catalysts than that over VMgO catalysts at the same reaction temperature.The highest yield of propene reached 23.1% at 500℃ and 6000h^(-1) space velocity.展开更多
A series ofnanosized cobalt oxide catalysts modified with phosphorus have been synthesized by the solgel method and investigated in the oxidative dehydrogenation of propane to propene. With the addition of phosphorus,...A series ofnanosized cobalt oxide catalysts modified with phosphorus have been synthesized by the solgel method and investigated in the oxidative dehydrogenation of propane to propene. With the addition of phosphorus, the crystallite size of the catalyst was largely decreased, while the P species in the catalyst were highly dispersed. Compared to pure cobalt oxide, the P-modified samples showed higher propane conversion and enhanced propene selectivity. Over the PCoO catalyst with a P/Co atomic ratio of 0.05, the maximal propene yields of 15.7% with a propane conversion of 28.3% were obtained at 520 ℃.展开更多
Hydrothermally synthesized mixed-phase MoVTeNbO_(x) catalysts are active for catalyzing the selective oxidation of propane to acrylic acid but suffer from the presence of the amorphous phase and low specific surface a...Hydrothermally synthesized mixed-phase MoVTeNbO_(x) catalysts are active for catalyzing the selective oxidation of propane to acrylic acid but suffer from the presence of the amorphous phase and low specific surface areas.Herein we report that HCl treatment preferentially y dissolves the amorphous phase in hydrothermally synthesized mixed-phase MoVTeNbOx catalysts and increases the catalytic performance.An optimal HCl treatment significantly increases the C3H8 conversion from 38.9%to 58.2% without changing the acrylic acid selectivity in the selective oxidation of propane to acrylic acid at 380°C.The original and HCl treated catalysts exhibit similar apparent activation energies,while HCl treatment increases the specific surface area,surface acid sites,surface V^(5+) density,and C_(3)H_(8) and C_(3)H_(6) irreversible adsorption amounts but decreases the C_(3)H_(8) and C_(3)H_(6) irreversible adsorption heats. The C_(3)H_(8) conversion rate is proportional to the surface V^(5+) density and C_(3)H_(8) irreversible adsorption amount, and the TOF is measured as 3.31 ± 0.08×10^(-5) s^(-1) at 340°C. Thus,HCl treatment enhances the catalytic performance of mixed-phase MoVTeNbO_(x) catalysts mainly by increasing the active site density rather than by increasing the active site activity. Our results provide an effective approach to prepare highly active mixed-phase MoVTeNbO_(x) catalysts for the selective oxidation of propane to acrylic acid.展开更多
Propane dehydrogenation using CO_(2)as a mild oxidizer(CO_(2)-ODP)is a promising technology for high propylene production and CO_(2)reduction utilization.Among them,the reverse water gas shift reaction(RWGS)can change...Propane dehydrogenation using CO_(2)as a mild oxidizer(CO_(2)-ODP)is a promising technology for high propylene production and CO_(2)reduction utilization.Among them,the reverse water gas shift reaction(RWGS)can change the reaction equilibrium to increase the propylene yield,and the Boudouard reaction can assist in the carbon accumulation elimination.However,the efficiency of the catalysts developed so far is limited,we introduced the Cr active component during the synthesis of porous silica spheres to form a CO_(2)-ODP catalyst,with a uniform distribution of active sites via(NH_(4))_(3)[CrMo_(6)O_(24)H_(6)]·7H_(2)O produce a derivative.As anα-type Anderson series of polyoxometalates(POMs),this six octahedral structure formed by Mo participation surrounds the central atom Cr,which is more stable in structure by electrostatic effect,its derivatives generated after calcination are stably bound to the silica-based carrier,which reduces the formation of inertα-Cr_(2)O_(3)by CrO_(x)aggregation during the catalytic process.Meanwhile,the oxygen atoms rich in polyoxometalates are more likely to form Si-O bonds with the carrier,which makes the active sites evenly and stably branched in the inner wall of the pores of mesoporous silica spheres,reduces the influence of carbon accumulation,and facilitates the activation and regeneration.The CO_(2)conversion of the catalyst CrMoO_(x)@mesoporous silica spheres(MSS)is typically greater than 20%under selected ideal conditions.This synthesis method of assembling POMs with mesoporous materials opens a new pathway for developing propane dehydrogenation catalysts.Compared to traditional impregnation synthesis,this catalyst contains a lower Cr content while achieving higher CO_(2)consumption efficiency.展开更多
ZnO could be a suitable catalyst for the oxidative conversion of CH4,C2H6 and C3H8.However,the main drawback is its thermal instability.Therefore,ZnO supported on ZrO 2,TiO2,γ-Al2O and SiO2 was investigated for the o...ZnO could be a suitable catalyst for the oxidative conversion of CH4,C2H6 and C3H8.However,the main drawback is its thermal instability.Therefore,ZnO supported on ZrO 2,TiO2,γ-Al2O and SiO2 was investigated for the oxidative dehydrogenation of propane and ethane,and the oxidative coupling of methane.The stability of the supported ZnO is partially improved,but ZnO reacts with the support material,forming new compounds （Zn-zirconates,-titanates,-aluminates and-silicates）,which already occurs below reaction temperature.This might also be the case for many other heterogeneous catalysts.展开更多
基金supported by the Ministry of Science and Technology of China (No. 2009AA06Z313,2009AA064803)
文摘A Pt/WO3/TiO2 catalyst for propane oxidation was prepared by a stepwise wet impregnation method, and was aged at 800°C for 5 hr. Compared to the sulfate-derived titania supported catalyst, the introduction of tungsten oxide as stable Br nsted acid sites led to the formation of more metallic platinum active sites at the Pt/WO3 interface. The dissociation of surface intermediates for propane oxidation was promoted on the WO3-modified catalyst. This, as well as the inhibition effects of tungsten oxide on the sintering of anatase and the phase transformation to rutile, resulting in a high activity and thermal stability for the Pt/WO3/TiO2 catalyst.
基金financially supported by the National Science and Technology Support Program of China(2012BAK13B01)
文摘Abstract： In order to study the flammability and explosion property of gases during the propane oxidation to acrylic acid process, the explosion limits and the safety oxygen content of gases at the recycle gas compressor outlet, the reactor inlet, and the reactor outlet were theoretically calculated and experimentally tested. Finally, the inert limit was also determined. It showed that gases at the recycle gas compressor outlet and the reactor outlet were nonflammable based on three indicators： the explosion limits, the safety oxygen content and the inert limit. The C3H6 and O2 contents were higher at the reactor inlet, which made the mixed gases easily ignitable. However, the large amount of inert gases suppressed the possibility of explo- sion effectively. As a consequence, no explosion phenomenon would happen in all three locations. But gases at the reactor inlet are most dangerous, where more supervision on the concentration of gases and more strict control on the temperature and pressure should be implemented. Besides this, open flame, hot surfaces and other sources of ignition are prohibited in working spaces. The experimental results can be applied to similar process for oxidation of propane.
基金financially supported by the National Key Research and Development Program of China(No.2019YFC1904500)Young Top Talents of Fujian Young Eagle Program。
文摘A series of nitrogen-doped CoAlO(N-CoAlO)were constructed by a hydrothermal route combined with a controllable NH_(3) treatment strategy.The effects of NH_(3) treatment on the physico-chemical properties and oxidation activities of N-Co AlO catalysts were investigated.In comparison to CoAlO,a smallest content decrease in surface Co^(3+)(serving as active sites)while a largest increased amount of surface Co^(2+)(contributing to oxygen species)are obtained over N-Co AlO/4h among the N-CoAlO catalysts.Meanwhile,a maximum N doping is found over N-CoAlO/4h.As a result,N-CoAlO/4h(under NH_(3) treatment at 400℃ for 4 hr)with rich oxygen vacancies shows optimal catalytic activity,with a T90(the temperature required to reach a 90% conversion of propane)at 266℃.The more oxygen vacancies are caused by the co-operative effects of N doping and suitable reduction of Co^(3+) for NCoAlO/4h,leading to an enhanced oxygen mobility,which in turn promotes C_(3)H_(8) total oxidation activity dominated by Langmuir-Hinshelwood mechanism.Moreover,in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTs)analysis shows that N doping facilities the decomposition of intermediate species(propylene and formate)into CO_(2)over the catalyst surface of N-CoAlO/4h more easily.Our reported design in this work will provide a promising way to develop abundant oxygen vacancies of Co-based catalysts derived from hydrotalcites by a simple NH_(3) treatment.
基金financially supported by the National Natural Science Foundation of China(No.22072069)the Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials(Wuhan University of Science and Technology No.WKDM202303).
文摘Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile surface-engineering strategy wherein NiCo_(2)O_(4) was treated with different alkali solvents was developed.The obtained catalyst(NiCo_(2)O_(4)-OH)showed a higher surface alkalinity and more surface defects compared to the pristine spinel oxide,including enhanced structural distortion as well as promoted oxygen vacancies.The propane oxidation ability of NiCo_(2)O_(4)-OH was greatly enhanced,with a propane conversion rate that was approximately 6.4 times higher than that of pristine NiCo_(2)O_(4) at a reaction temperature 193℃.This work sets a valuable paradigm for the surface modulation of spinel oxide via alkali treatment to ensure a high-performance oxidation catalyst.
文摘Directional design of efficient catalysts for volatile organic compounds degradation remains a complex,yet effective and challenging process.Herein,oxygen-rich vacancy Co_(3)O_(4)-anchored Pt catalysts were prepared through atom-trapping strategy and relevant vacancy defect inductive effect was proposed.The 0.6Pt/VO-Co_(3)O_(4)catalyst presented a reaction rate value of 32.2×10^(-5)mol·g_(cat)^(-1)·s^(-1)at 160℃for catalytic propane total oxidation,which was nearly 5 times the reaction rate of Co_(3)O_(4)(6.7×10^(-5)mol·g_(cat)^(-1)·s^(-1)).Also,it exhibited excellent water-resistance and catalytic stability.The Pt atoms were stabilized on the Co_(3)O_(4)surface by vacancy defects to improve dispersion.Meanwhile,the vacancy defect inductive effect induced stronger electron interaction between Pt and Co_(3)O_(4)on the surface,thus promote the redox ability at low-temperature.The mobility and oxygen-activating ability of surface lattice oxygen were also strengthened by the vacancy defect inductive effect.This facilitated the generation of more surface-active oxygen species for the cleavage of C-H bond and the deep oxidation of intermediate species.Overall,this study proposed a novel concept the fabrication of highly efficient catalysts for the purpose of catalytic oxidation.
文摘Ammonium salts, （NH4）6HPMo11MO40 （M = Ni, Co, Fe）, have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9 ℃/min. They were characterized by BET method, XRD, 31p NMR, UV-Vis and IR techniques. The catalysts were found active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9 ℃/min.
文摘The effects of metal atomic ratio, water content, oxygen content, and calcination temperature on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid have been investigated and discussed. Among the catalysts studied, it was found that the MoVTeNbO catalyst calcined at a temperature of 600 ℃ showed the best performance in terms of propane conversion and selectivity for acrylic acid under an atmosphere of nitrogen. An effective MoVTeNbO oxide catalyst for propane selective oxidation to acrylic acid was obtained with a combination of a preferred metal atomic ratio （Mo1V0.31Te0.23Nb0.12）. The optimum reaction condition for the selective oxidation of propane was the molar ratio of C3H8 ：O2 ： H2O ： N2 = 4.4： 12.8 ： 15.3 ： 36.9. Under such conditions, the conversion of propane and the maximum yield of acrylic acid reached about 50% and 21%, respectively.
文摘The effects of chemical composition and preparation conditions,especially calcination atmosphere and water content on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid were investigated.Among the catalysts studied,Mo_(1.0)V_(0.3)Te_(0.23)Nb_(0.12)O_(x) catalyst calcined in inert atmosphere at 600℃shows the best performance in terms of propane conversion and selectivity to acrylic acid.The results reveal that proper chemical composition, calcination atmosphere and water content affect greatly the catalysts in many ways including structure,chemical composition,which are related to their catalytic performances;and 51.0%propane conversion and 30.5%one-pass yield to acrylic acid can be achieved at the same time.
基金The work is supported by The Department of Education of Heilongjiang Province.
文摘Selective oxidation of propane by lattice oxygen of vanadium-phosphorus oxide(VPO) catalysts was investigated with a pulse reactor in which the oxidation of propane and there-oxidation of catalyst were implemented alternately in the presence of water vapor. The principalproducts are acrylic acid (AA), acetic acid (HAc), and carbon oxides. In addition, small amounts ofC_1 and C_2 hydrocarbons were also found, molar ratio of AA to HAc is 1.4-2.2. The active oxygenspecies are those adsorbed on catalyst surface firmly and/or bound to catalyst lattice, i.e. latticeoxygen; the selective oxidation of propane on VPO catalysts can be carried out in a circulatingfluidized bed (CFB) riser reactor. For propane oxidation over VPO catalysts, the effects of reactiontemperature in a pulse reactor were found almost the same as in a steady-state flow reactor. Thatis, as the reaction temperature increases, propane conversion and the amount of C_1+C_2 hydrocarbonsin the product increase steadily, while selectivity to acrylic acid and to acetic acid increaseprior to 350℃ then begin to drop at temperatures higher than 350℃, and yields of acrylic acid andof acetic acid attained maximum at about 400℃. The maximum yields of acrylic acid and of aceticacid for a single-pass are 7.50% and 4.59% respectively, with 38.2% propane conversion. When theamount of propane pulsed decreases or the amount of catalyst loaded increases, the conversionincreases but the selectivity decreases. Increasing the flow rate of carrier gases causes theconversion pass through a minimum but selectivity and yields pass through a maximum. In a fixed bedreactor, it is hard to obtain high selectivity at a high reaction conversion due to the furtherdegradation of acrylic acid and acetic acid even though propane was oxidized by the lattice oxygen.The catalytic performance can be improved in the presence of excess propane. Propylene can beoxidized by lattice oxygen of VPO catalyst at 250℃, nevertheless, selectivity to AA and to HAc areeven lower, much more acetic acid was produced (molar ratio of AA to HAc is 0.19:1-0.83:1) thoughthe oxidation products are the same as from propane.
文摘Alkaline earth metal （Mg,Ca,Sr and Ba）-doped Mo-V-Sb-O x catalysts,prepared by a dry-up method,have been investigated for their catalytic performance in the oxidation of propane under different reaction conditions.The catalysts have been characterized by N2 adsorption-desorption,temperature-programmed desorption （TPD） of NH3,SEM and XRD.Influence of water vapor on the catalytic performance,particularly on the selectivities to acetic acid and acrylic acid,has also been studied.The selectivity to acrylic acid was improved significantly by the doping of alkaline earth metals to Mo-V-Sb-O x catalysts.The surface acidic sites of the catalyst decreased with the doping of the catalyst with alkaline earth metals,which ultimately was found to be beneficial for obtaining high selectivity to acrylic acid.The catalytic activity and product selectivities were found to be influenced by the reaction temperature,C3H8/O2 ratio and space velocity.A significant improvement in the selectivity to acrylic acid has also been observed by the addition of water vapor in the feed of propane and oxygen in the oxidation of propane.
基金was supported by the National Natural Science Foundation of China(91545113,21703050)the China Postdoctoral Science Foundation(2017M610363,2018T110584)+2 种基金Shell Global Solutions International B.V.(PT71423,PT74557)the Fok Ying Tong Education Foundation(131015)the Science&Technology Program of Ningbo(2017C50014)~~
文摘Thermal stability has long been recognized as a major limitation for the application of ligand modification in high-temperature reactions. Herein, we demonstrate polymeric phosphate as an efficient and stable ligand to tune the selectivity of propane oxidative dehydrogenation. Beneficial from the weakened affinity of propene, NiO modified with polymeric phosphate shows a selectivity 2–3 times higher than NiO towards the production of propene. The success of this regulation verifies the feasibility of ligand modification in high-temperature gas-phase reactions and shines a light on its applications in other important industrial reactions.
基金supported by the National Natural Science Foundation of China (20776089)the New Century Excellent Talent Project of China(NCET-05-0783)
文摘In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane （ODHP）. The techniques of temperature-programmed reduction with H2 （H2-TPR）, N2 adsorption-desolption, Fourier transform infrared spectroscopy （FT-IR）, X-ray diffraction （XRD） and X-ray photoelectron spectra （XPS） were employed for catalyst characterization. It is found that the activity of the catalysts for ODHP increases first and then decreases with the increase of Mo content. The catalyst with a Mo/Ni atomic ratio of 1/1 exhibits the best catalytic activity, which gives the propene selectivity of 81.4% at a propane conversion of 11.3% under 600 ~C and maintains the good catalytic performance for 22 h on stream. This is related not only to its high reducibility and dispersion as revealed by TPR and XRD, but also to the formation of more selective oxygen species on the MoOz-NiO interface as identified by XPS.
文摘An industrial scale propylene production via oxidative dehydrogenation of propane （ODHP） in multi-tubular re- actors was modeled. Multi-tubular fixed-bed reactor used for ODHP process, employing 10000 of small diameter tubes immersed in a shell through a proper coolant flows. Herein, a theory-based pseudo-homogeneous model to describe the operation of a fixed bed reactor for the ODHP to correspondence olefln over V2O5/γ-Al203 catalyst was presented. Steady state one dimensional model has been developed to identify the operation parameters and to describe the propane and oxygen conversions, gas process and coolant temperatures, as well as other pa- rameters affecting the reactor performance such as pressure. Furthermore, the applied model showed that a double-bed multitubular reactor with intermediate air injection scheme was superior to a single-bed design due to the increasing of propylene selectivity while operating under lower oxygen partial pressures resulting in propane conversion of about 37.3%. The optimized length of the reactor needed to reach 100% conversion of the oxygen was theoretically determined. For the single-bed reactor the optimized length of 11.96 m including 0.5 m of inert section at the entrance region and for the double-bed reactor design the optimized lengths of 5.72 m for the first and 7.32 m for the second reactor were calculated. Ultimately, the use of a distributed oxygen feed with limited number of injection points indicated a significant improvement on the reactor performance in terms of propane conversion and propylene selectivity. Besides, this concept could overcome the reactor run- away temperature problem and enabled operations at the wider range of conditions to obtain enhanced propyl- ene production in an industrial scale reactor.
基金the Doctoral Program of Higher Education(No. SRFDP-2012009111001)NNSFC(No. 21202141)+1 种基金Priority Academic Program Development(PAPD) of Jiangsu Higher Education Institutions, Key Science & Technology Specific Projects of Yangzhou(No. YZ20122029)Yangzhou Nature Science Foundation(No. YZ2014040) for financial support
文摘PtSnNa/γ-Al2O3 catalyst is widely used in the dehydrogenation of light alkane. This paper reports a new fabrication method of the catalyst. In the work, γ-Al2O3, SnCl4 and NaCl were ball milled to upload Sn and Na＋ onto the support instead of the conventionally used immersion method. The subsequent baking procedures frimly fixed Sn onto the support, which could disperse Pt introduced by immersion. The effects of Sn and Na＋ additives on the catalytic performance of PtSnNa/y-Al2O3 catalyst were investigated. It was found that the appropriate molar ratio of Sn/Pt was 6：1 while the favorable weight percentage of Na＋ was 0.90%. Compared with the reaction catalyzed by the industrially employed PtSnNa/ γ-Al2O3 catalyst, the conversion of propane and the selectivity of propylene had been greatly improved, which were 26.97%; and 99.18% respectivelv after 12 h reaction.
基金This work received financial support from the National Natural Science Foundation of China(21902116)Scientific Research Foundation of Technology Department of Liaoning province of China(2022-MS-379)Liaoning Revitalization Talents Program(XLYC1902070).
文摘Oxidative dehydrogenation of propane is an attractive route for the synthesis of propylene due to its favorable thermodynamic and kinetic characteristics, however, it is challenging to realize high selectivity towards propylene. Recently, it has been discovered that boron nitride (BN) is a promising catalyst that affords superior selectivity towards propylene in oxidative dehydrogenation of propane. Summarizing the progress and unravelling the reaction mechanism of BN in oxidative dehydrogenation of propane are of great significance for the rational design of efficient catalysts in the future. Herein, in this review, the underlying reaction mechanisms of oxidative dehydrogenation of propane over BN are extracted;the developed BN catalysts are classified into pristine BN, functionalized BN, supported BN and others, and the applications of each category of BN catalysts in oxidative dehydrogenation of propane are summarized;the challenges and opportunities on oxidative dehydrogenation of propane over BN are pointed out, aiming to inspire more studies and advance this research field.
文摘Oxidative dehydrogenation of propane over V-Mg-O and MCl_n(M=Cu^+,Li^+, Ag^+,Cd^(2+))promoted V-Mg-O catalysts was studied.XRD result showed that the V-Mg-O catalysts were composed of MgO and Mg_3(VO_4)_2.The yield of propene was much higher over CuCl and LiCl promoted VMgO catalysts than that over VMgO catalysts at the same reaction temperature.The highest yield of propene reached 23.1% at 500℃ and 6000h^(-1) space velocity.
基金supported by the National Basic Research Program of China(Nos.2010CB732303 and 2013CB933102)the National Natural Science Foundation of China(Nos.21073148 and 21033006)the Program for Innovative Research Team of the Ministry of Education of China(No.IRT1036)
文摘A series ofnanosized cobalt oxide catalysts modified with phosphorus have been synthesized by the solgel method and investigated in the oxidative dehydrogenation of propane to propene. With the addition of phosphorus, the crystallite size of the catalyst was largely decreased, while the P species in the catalyst were highly dispersed. Compared to pure cobalt oxide, the P-modified samples showed higher propane conversion and enhanced propene selectivity. Over the PCoO catalyst with a P/Co atomic ratio of 0.05, the maximal propene yields of 15.7% with a propane conversion of 28.3% were obtained at 520 ℃.
基金the National Key R&D Program of MOST(2021YFA1501301)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0450102)+2 种基金the National Natural Science Foundation of China(22202189)the Changjiang Scholars Program of Ministry of Education of Chinathe Instruments Center for Physical Science,University of Science and Technology of China.
文摘Hydrothermally synthesized mixed-phase MoVTeNbO_(x) catalysts are active for catalyzing the selective oxidation of propane to acrylic acid but suffer from the presence of the amorphous phase and low specific surface areas.Herein we report that HCl treatment preferentially y dissolves the amorphous phase in hydrothermally synthesized mixed-phase MoVTeNbOx catalysts and increases the catalytic performance.An optimal HCl treatment significantly increases the C3H8 conversion from 38.9%to 58.2% without changing the acrylic acid selectivity in the selective oxidation of propane to acrylic acid at 380°C.The original and HCl treated catalysts exhibit similar apparent activation energies,while HCl treatment increases the specific surface area,surface acid sites,surface V^(5+) density,and C_(3)H_(8) and C_(3)H_(6) irreversible adsorption amounts but decreases the C_(3)H_(8) and C_(3)H_(6) irreversible adsorption heats. The C_(3)H_(8) conversion rate is proportional to the surface V^(5+) density and C_(3)H_(8) irreversible adsorption amount, and the TOF is measured as 3.31 ± 0.08×10^(-5) s^(-1) at 340°C. Thus,HCl treatment enhances the catalytic performance of mixed-phase MoVTeNbO_(x) catalysts mainly by increasing the active site density rather than by increasing the active site activity. Our results provide an effective approach to prepare highly active mixed-phase MoVTeNbO_(x) catalysts for the selective oxidation of propane to acrylic acid.
基金financial support by“Grassland Talents”of Inner Mongolia Autonomous Region,Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(No.NJYT23030)Technology Breakthrough Engineering Hydrogen Energy Field"Unveiling and Leading"Project(No.2024KJTW0018)+4 种基金“Steed plan High level Talents”of Inner Mongolia University,Carbon neutralization research project(No.STZX202218)the National Natural Science Foundation of China(No.U22A20107)Inner Mongolia Autonomous Region Natural Science Foundation(No.2023MS02002)Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion(No.MATEC2024KF011)National Key R&D Program of China(No.2022YFA1205201).
文摘Propane dehydrogenation using CO_(2)as a mild oxidizer(CO_(2)-ODP)is a promising technology for high propylene production and CO_(2)reduction utilization.Among them,the reverse water gas shift reaction(RWGS)can change the reaction equilibrium to increase the propylene yield,and the Boudouard reaction can assist in the carbon accumulation elimination.However,the efficiency of the catalysts developed so far is limited,we introduced the Cr active component during the synthesis of porous silica spheres to form a CO_(2)-ODP catalyst,with a uniform distribution of active sites via(NH_(4))_(3)[CrMo_(6)O_(24)H_(6)]·7H_(2)O produce a derivative.As anα-type Anderson series of polyoxometalates(POMs),this six octahedral structure formed by Mo participation surrounds the central atom Cr,which is more stable in structure by electrostatic effect,its derivatives generated after calcination are stably bound to the silica-based carrier,which reduces the formation of inertα-Cr_(2)O_(3)by CrO_(x)aggregation during the catalytic process.Meanwhile,the oxygen atoms rich in polyoxometalates are more likely to form Si-O bonds with the carrier,which makes the active sites evenly and stably branched in the inner wall of the pores of mesoporous silica spheres,reduces the influence of carbon accumulation,and facilitates the activation and regeneration.The CO_(2)conversion of the catalyst CrMoO_(x)@mesoporous silica spheres(MSS)is typically greater than 20%under selected ideal conditions.This synthesis method of assembling POMs with mesoporous materials opens a new pathway for developing propane dehydrogenation catalysts.Compared to traditional impregnation synthesis,this catalyst contains a lower Cr content while achieving higher CO_(2)consumption efficiency.
基金supported by the Deutsche Forschungsgemeinschaft (DFG) within the Framework of the German Initiative for Excellence
文摘ZnO could be a suitable catalyst for the oxidative conversion of CH4,C2H6 and C3H8.However,the main drawback is its thermal instability.Therefore,ZnO supported on ZrO 2,TiO2,γ-Al2O and SiO2 was investigated for the oxidative dehydrogenation of propane and ethane,and the oxidative coupling of methane.The stability of the supported ZnO is partially improved,but ZnO reacts with the support material,forming new compounds （Zn-zirconates,-titanates,-aluminates and-silicates）,which already occurs below reaction temperature.This might also be the case for many other heterogeneous catalysts.
