A series of CuO/ZnO/Al_2O_3, CuO/ZnO/ZrO_2/Al_2O_3 and CuO/ZnO/CeO_2/Al_2O_3 catalysts were prepared by coprecipitation and characterized by N_2 adsorption, XRD, TPR, N_2O titration and HRTEM. The catalytic performanc...A series of CuO/ZnO/Al_2O_3, CuO/ZnO/ZrO_2/Al_2O_3 and CuO/ZnO/CeO_2/Al_2O_3 catalysts were prepared by coprecipitation and characterized by N_2 adsorption, XRD, TPR, N_2O titration and HRTEM. The catalytic performances of these catalysts for the steam reforming of methanol were evaluated in a laboratory-scale fixed-bed reactor at 0.1 MPa and temperatures between 473 and 543 K. The results showed that the catalytic activity depended greatly on the catalyst reducibility and the specific surface area of Cu. An approximate linear correlation between the catalytic activity and the Cu surface area was found for all catalysts investigated in this study.Compared to CuO/ZnO/Al_2O_3, the ZrO_2-doped CuO/ZnO/Al_2O_3 exhibited higher activity and selectivity to CO,while the CeO_2-doped catalyst displayed lower activity and selectivity. Finally, an intrinsic kinetic study was carried out over a screened CuO/ZnO/CeO_2/Al_2O_3 catalyst in the absence of internal and external mass transfer effects. A good agreement was observed between the model-derived effluent concentrations of CO(CO_2) and the experimental data. The activation energies for the reactions of methanol-steam reforming, water-gas shift and methanol decomposition over CuO/ZnO/CeO_2/Al_2O_3 were 93.1, 85.1 and 116.5 k J·mol^(-1), respectively.展开更多
Synergy between the intrinsic photon and thermal effects from full-spectrum sunlight for H_(2) production is considered to be central to further improve solar-driven H_(2) production.To that end,the photo-thermocataly...Synergy between the intrinsic photon and thermal effects from full-spectrum sunlight for H_(2) production is considered to be central to further improve solar-driven H_(2) production.To that end,the photo-thermocatalyst that demonstrates both photoelectronic and photothermal conversion capabilities have drawn much attention recently.Here,we propose a novel synergistic full-spectrum photo-thermo-catalysis technique for high-efficient H_(2) production by solar-driven methanol steam reforming(MSR),along with the Pt-Cu Oxphoto-thermo-catalyst featuring Pt-Cu/Cu_(2)O/CuO heterojunctions by Pt-mediated in-situ photoreduction of Cu O.The results show that the H_(2) production performance rises superlinearly with increasing light intensity.The optimal H_(2) production rate of 1.6 mol g^(-1) h^(-1) with the corresponding solar-to-hydrogen conversion efficiency of 7%and the CO selectivity of 5%is achieved under 15×sun full-spectrum irradiance(1×sun=1 k W m^(-2))at 180°C,which is much more efficient than the previously-reported Cu-based thermo-catalysts for MSR normally operating at 250~350°C.These attractive performances result from the optimized reaction kinetics in terms of intensified intermediate adsorption and accelerated carrier transfer by long-wave photothermal effect,and reduced activation barrier by short-wave photoelectronic effect,due to the broadened full-spectrum absorbability of catalyst.This work has brought us into the innovative technology of full-spectrum synergistic photothermo-catalysis,which is envisioned to expand the application fields of high-efficient solar fuel production.展开更多
Steam reforming of methanol was carried out on the copper-silica aerogel catalyst.The effects of reaction temperature,feed rate,water to methanol molar ratio and carrier gas flowrate on the H_2 production rate and CO ...Steam reforming of methanol was carried out on the copper-silica aerogel catalyst.The effects of reaction temperature,feed rate,water to methanol molar ratio and carrier gas flowrate on the H_2 production rate and CO selectivity were investigated.M ethanol conversion was increased considerably in the range of about 240-300,after which it increased at a slightly lower rate.The used feed flowrate,steam to methanol molar ratio and carrier gas flowwere 1.2-9.0 m L/h,1.2-5.0 and 20-80 m L/min,respectively.Reducing the feed flowrate increased the H_2 production rate.It was found that an increase in the water to methanol ratio and decreasing the carrier gas flowrate slightly increases the H2production rate.Increasing the water to methanol ratio causes the lowest temperature in which CO formation was observed to rise,so that for the ratio of 5.0 no CO formation was detected in temperatures lower than 375℃.In all conditions,by approaching the complete conversion,increasing the main product concentration,increasing the temperature and contact time,and decreasing the steam to methanol ratio,the CO selectivity was increased.These results suggested that CO was formed as a secondary product through reverse water-gas shift reaction and did not participate in the methanol steam reforming reaction mechanism.展开更多
Methanol-to-olefins(MTO)is industrially applied to produce ethylene and propylene using methanol converted from coal,synthetic gas,and biomass.SAPO-34 zeolites,as the most efficient catalyst in MTO process,are subject...Methanol-to-olefins(MTO)is industrially applied to produce ethylene and propylene using methanol converted from coal,synthetic gas,and biomass.SAPO-34 zeolites,as the most efficient catalyst in MTO process,are subject to the rapid deactivation due to coke deposition.Recent work shows that steam regeneration can provide advantages such as low carbon dioxide emission and enhanced light olefins yield in MTO process,compared to that by air regeneration.A kinetic study on the steam regeneration of spent SAPO-34 catalyst has been carried out in this work.In doing so,we first investigated the effect of temperature on the regeneration performance by monitoring the crystal structure,acidity,residual coke properties and other structural parameters.The results show that with the increase of regeneration temperature,the compositions of residual coke on the catalyst change from pyrene and phenanthrene to naphthalene,which are normally considered as active hydrocarbon pool species in MTO reaction.However,when the regeneration temperature is too high,nitrogen oxides can be found in the residual coke.Meanwhile,as the regeneration temperature increases,the quantity of residual coke reduces and the acidity,BET surface area and pore structure of the regenerated samples can be better recovered,resulting in prolonging catalyst lifetime.We have further derived the kinetics of steam regeneration,and obtained an activation energy of about 177.8 kJ·mol^(-1).Compared that with air regeneration,the activation energy of steam regeneration is higher,indicating that the steam regeneration process is more difficult to occur.展开更多
Hydrogen production by partial oxidation steam reforming of methanol over a Cu/ZnO/Al2 O3 cata
lyst has been paid more and more attention. The chemical equilibria involved in the methanol partial oxidation
steam refo...Hydrogen production by partial oxidation steam reforming of methanol over a Cu/ZnO/Al2 O3 cata
lyst has been paid more and more attention. The chemical equilibria involved in the methanol partial oxidation
steam reforming reaction network such as methanol partial oxidation, methanol steam reforming, decomposition
of methanol and water-gas shift reaction have been examined over the ranges of temperature 473-1073 K under
normal pressure. Based on the detailed kinetics of these reactions over a Cu/ZnO/Al2O3 catalyst, and from the
basic concept of the effectiveness factor, the intraparticle diffusion limitations were taken into account. The effec
tiveness factors for each reaction along the bed length were calculated. Then important results were offered for the
simulation of this reaction process.展开更多
The catalytic performances of methanol steam reforming reactions on CuZn(Zr)AIO catalysts were studied. When the ZrO2 promoter was added to a CuZnAIO catalyst, its methanol conversion, H2 production and H2 selectivity...The catalytic performances of methanol steam reforming reactions on CuZn(Zr)AIO catalysts were studied. When the ZrO2 promoter was added to a CuZnAIO catalyst, its methanol conversion, H2 production and H2 selectivity improved greatly. By using the (?)COPZr-2 catalyst as an example, which exhibited the best catalytic performance, the optimized reaction conditions were established to be: 250℃, 0.1 MPa, H2O/MeOH=1.3, WHSV=3.56 h-1, and without carrier gas. A 150 h stability test of the (?)COPZr-2 catalyst showed that the catalyst had good stability, as the methanol conversion and H2 production could be kept at 88% and 83% respectively. Moreover, outlet H2 and CO contents were>63% and 0.20%-0.31%, respectively.展开更多
Cu/ZnAlO catalysts derived from hydroxycarbonate precursors containinghydrotalcite-like layered double hydroxides (LDHs) were studied. The influence on the performanceof the catalysts was also studied when the Al in t...Cu/ZnAlO catalysts derived from hydroxycarbonate precursors containinghydrotalcite-like layered double hydroxides (LDHs) were studied. The influence on the performanceof the catalysts was also studied when the Al in the Cu/ZnAlO catalyst was partly or completelyreplaced by Zr or Ce.展开更多
In this study, the laminated porous metal fiber sintered felt(PMFSF) functioning as catalyst support was used in a cylindrical methanol steam reforming(MSR) microreactor for hydrogen production. The PMFSF was fabricat...In this study, the laminated porous metal fiber sintered felt(PMFSF) functioning as catalyst support was used in a cylindrical methanol steam reforming(MSR) microreactor for hydrogen production. The PMFSF was fabricated by the low temperature solid-phase sintering method using metal fibers such as copper fibers and aluminum fibers which are obtained by the multi-tooth cutting method. The two-layer impregnation method was employed to coat Cu/Zn/Al/Zr catalyst on the PMFSF. The effect of fiber material, uniform porosity and gradient porosity on the performance of methano steam reforming microreactor was studied by varying the gas hourly space velocity(GHSV) and reaction temperature. Our results showed that the loading strength of porous copper fiber sintered felt(PCFSF) was better than porous aluminum fiber sintered felt(PAFSF). Under the same reaction conditions, the PCFSF showed higher methanol conversion and more H_2 output than PAFSF. Moreover, the gradient porosity(Type 5: 90%×80%×70%) of PMFSF used as the catalyst support in microreactor demonstrated a best reaction performance for hydrogen production.展开更多
Methanol steam reforming(MSR) is an attractive approach to produce hydrogen for fuel cells.Due to the limited catalyst loading volume and frequent start-ups and shut-downs on board,it is highly desired to develop an e...Methanol steam reforming(MSR) is an attractive approach to produce hydrogen for fuel cells.Due to the limited catalyst loading volume and frequent start-ups and shut-downs on board,it is highly desired to develop an extremely active and robust catalyst.Herein,on the basis of industrial Cu/ZnO/Al_(2) O_(3) catalysts,a series of CuZnAl-xMg catalysts with enhanced Cu-ZnO synergy were synthesized via magnesium assisted strategy.The incorporation of magnesium was found to be beneficial to the enhancement of catalytic activity and stability of catalyst.A combination of complementa ry characterizations(e.g.XRD,H_(2)-TPR,N_(2) O chemisorption,TEM,XPS analysis etc.) proves that isomorphous substitution of Cu^(2+)in malachite phase gives rise to more dispersive Cu and ZnO NPs,and the increased Cu^(+)/Cu~0 ratio indicates the strengthened Cu-ZnO synergy effect,which leads to the boosted stability during the thermal treatment.展开更多
In this study, the catalyst composition in binary ZnO-Al<sub>2</sub>O<sub>3</sub> catalyst was initially evaluated and optimized for methanol steam reforming. Then different Na contents were lo...In this study, the catalyst composition in binary ZnO-Al<sub>2</sub>O<sub>3</sub> catalyst was initially evaluated and optimized for methanol steam reforming. Then different Na contents were loaded by an incipient wetness impregnation method onto the optimized ZnAl catalyst. It was found that the activity was greatly enhanced by the modification of Na, which depended on the Na content in the catalyst. The methanol conversion was 96% on a 0.1 Na/0.4 ZnAl catalyst (GHSV = 14,040 h<sup>-</sup><sup>1</sup>, S/C = 1.4, 350°C), which was much higher with respect to a Na-free 0.4 ZnAl catalyst (74%). The remarkable improvement of activity was attributed to a weakening of the C-H bonds and clear of hydroxyl group by the Na dopant leading to an accelerated dehydrogenation of the reaction intermediates formed on ZnAl<sub>2</sub>O<sub>4</sub> spinel surface and thus the overall reaction.展开更多
A novel design of plate-type microchannel reactor has been developed for fuel cell-grade hydrogen production.Commercial Cu/Zn/Al2O3 was used as catalyst for the reforming reaction,and its effectiveness was evaluated o...A novel design of plate-type microchannel reactor has been developed for fuel cell-grade hydrogen production.Commercial Cu/Zn/Al2O3 was used as catalyst for the reforming reaction,and its effectiveness was evaluated on the mole fraction of products,methanol conversion,hydrogen yield and the amount of carbon monoxide under various operating conditions.Subsequently,0.5 wt% Ru/Al2O3 as methanation catalyst was prepared by impregnation method and coupled with MSR step to evaluate the capability of methanol processor for CO reduction.Based on the experimental results,the optimum conditions were obtained as feed flow rate of 5mL/h and temperature of 250℃,leading to a low CO selectivity and high H2 yield.The designed reformer with catalyst coated layer was compared with the conventional packed bed reformer at the same operating conditions.The constructed fuel processor had a good performance and excellent capability for on-board hydrogen production.展开更多
The on-board methanol steam reforming(MSR) has long been considered as an effective approach to insitu produce hydrogen for fuel cell vehicles(FCVs). However, the conventional MSR catalyst pellets suffer from easy bre...The on-board methanol steam reforming(MSR) has long been considered as an effective approach to insitu produce hydrogen for fuel cell vehicles(FCVs). However, the conventional MSR catalyst pellets suffer from easy breakage during the vehicle movement, leading to increased pressure drop and reduced system stability. Herein, we introduce an integrated method to prepare the highly controlled structured catalysts based on coupled processes: direct prototyping the structured substrate using digital light processing(DLP) 3D printing technology, in-situ dynamic crystallization of active components assisted by magnetic resonance imaging(MRI) and calcination. The synthesized catalyst owns a gradient layer of active component, and exhibits better MSR performance, higher mechanical strength, reduced pressure drop, higher Cu dispersion and better adhesion of active compounds when compared with the conventional powder and pellet catalysts. The demonstrated successful application proves the feasibility of developed method,which has great potential to be used for preparing precisely other monolithic catalysts with customized structures.展开更多
基金Supported by the National Natural Science Foundation of China(21276076)the Program for New Century Excellent Talents in University(NCET-13-0801)the"111"Project(B08021)
文摘A series of CuO/ZnO/Al_2O_3, CuO/ZnO/ZrO_2/Al_2O_3 and CuO/ZnO/CeO_2/Al_2O_3 catalysts were prepared by coprecipitation and characterized by N_2 adsorption, XRD, TPR, N_2O titration and HRTEM. The catalytic performances of these catalysts for the steam reforming of methanol were evaluated in a laboratory-scale fixed-bed reactor at 0.1 MPa and temperatures between 473 and 543 K. The results showed that the catalytic activity depended greatly on the catalyst reducibility and the specific surface area of Cu. An approximate linear correlation between the catalytic activity and the Cu surface area was found for all catalysts investigated in this study.Compared to CuO/ZnO/Al_2O_3, the ZrO_2-doped CuO/ZnO/Al_2O_3 exhibited higher activity and selectivity to CO,while the CeO_2-doped catalyst displayed lower activity and selectivity. Finally, an intrinsic kinetic study was carried out over a screened CuO/ZnO/CeO_2/Al_2O_3 catalyst in the absence of internal and external mass transfer effects. A good agreement was observed between the model-derived effluent concentrations of CO(CO_2) and the experimental data. The activation energies for the reactions of methanol-steam reforming, water-gas shift and methanol decomposition over CuO/ZnO/CeO_2/Al_2O_3 were 93.1, 85.1 and 116.5 k J·mol^(-1), respectively.
基金financially supported by the National Natural Science Foundation of China(52176202)the Foshan Xianhu-Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory(41200101)。
文摘Synergy between the intrinsic photon and thermal effects from full-spectrum sunlight for H_(2) production is considered to be central to further improve solar-driven H_(2) production.To that end,the photo-thermocatalyst that demonstrates both photoelectronic and photothermal conversion capabilities have drawn much attention recently.Here,we propose a novel synergistic full-spectrum photo-thermo-catalysis technique for high-efficient H_(2) production by solar-driven methanol steam reforming(MSR),along with the Pt-Cu Oxphoto-thermo-catalyst featuring Pt-Cu/Cu_(2)O/CuO heterojunctions by Pt-mediated in-situ photoreduction of Cu O.The results show that the H_(2) production performance rises superlinearly with increasing light intensity.The optimal H_(2) production rate of 1.6 mol g^(-1) h^(-1) with the corresponding solar-to-hydrogen conversion efficiency of 7%and the CO selectivity of 5%is achieved under 15×sun full-spectrum irradiance(1×sun=1 k W m^(-2))at 180°C,which is much more efficient than the previously-reported Cu-based thermo-catalysts for MSR normally operating at 250~350°C.These attractive performances result from the optimized reaction kinetics in terms of intensified intermediate adsorption and accelerated carrier transfer by long-wave photothermal effect,and reduced activation barrier by short-wave photoelectronic effect,due to the broadened full-spectrum absorbability of catalyst.This work has brought us into the innovative technology of full-spectrum synergistic photothermo-catalysis,which is envisioned to expand the application fields of high-efficient solar fuel production.
文摘Steam reforming of methanol was carried out on the copper-silica aerogel catalyst.The effects of reaction temperature,feed rate,water to methanol molar ratio and carrier gas flowrate on the H_2 production rate and CO selectivity were investigated.M ethanol conversion was increased considerably in the range of about 240-300,after which it increased at a slightly lower rate.The used feed flowrate,steam to methanol molar ratio and carrier gas flowwere 1.2-9.0 m L/h,1.2-5.0 and 20-80 m L/min,respectively.Reducing the feed flowrate increased the H_2 production rate.It was found that an increase in the water to methanol ratio and decreasing the carrier gas flowrate slightly increases the H2production rate.Increasing the water to methanol ratio causes the lowest temperature in which CO formation was observed to rise,so that for the ratio of 5.0 no CO formation was detected in temperatures lower than 375℃.In all conditions,by approaching the complete conversion,increasing the main product concentration,increasing the temperature and contact time,and decreasing the steam to methanol ratio,the CO selectivity was increased.These results suggested that CO was formed as a secondary product through reverse water-gas shift reaction and did not participate in the methanol steam reforming reaction mechanism.
基金the National Natural Science Foundation of China(91834302)。
文摘Methanol-to-olefins(MTO)is industrially applied to produce ethylene and propylene using methanol converted from coal,synthetic gas,and biomass.SAPO-34 zeolites,as the most efficient catalyst in MTO process,are subject to the rapid deactivation due to coke deposition.Recent work shows that steam regeneration can provide advantages such as low carbon dioxide emission and enhanced light olefins yield in MTO process,compared to that by air regeneration.A kinetic study on the steam regeneration of spent SAPO-34 catalyst has been carried out in this work.In doing so,we first investigated the effect of temperature on the regeneration performance by monitoring the crystal structure,acidity,residual coke properties and other structural parameters.The results show that with the increase of regeneration temperature,the compositions of residual coke on the catalyst change from pyrene and phenanthrene to naphthalene,which are normally considered as active hydrocarbon pool species in MTO reaction.However,when the regeneration temperature is too high,nitrogen oxides can be found in the residual coke.Meanwhile,as the regeneration temperature increases,the quantity of residual coke reduces and the acidity,BET surface area and pore structure of the regenerated samples can be better recovered,resulting in prolonging catalyst lifetime.We have further derived the kinetics of steam regeneration,and obtained an activation energy of about 177.8 kJ·mol^(-1).Compared that with air regeneration,the activation energy of steam regeneration is higher,indicating that the steam regeneration process is more difficult to occur.
基金the grant of Post-Doc. Program, Kyungpook National University (1999).
文摘Hydrogen production by partial oxidation steam reforming of methanol over a Cu/ZnO/Al2 O3 cata
lyst has been paid more and more attention. The chemical equilibria involved in the methanol partial oxidation
steam reforming reaction network such as methanol partial oxidation, methanol steam reforming, decomposition
of methanol and water-gas shift reaction have been examined over the ranges of temperature 473-1073 K under
normal pressure. Based on the detailed kinetics of these reactions over a Cu/ZnO/Al2O3 catalyst, and from the
basic concept of the effectiveness factor, the intraparticle diffusion limitations were taken into account. The effec
tiveness factors for each reaction along the bed length were calculated. Then important results were offered for the
simulation of this reaction process.
基金This work is supported by the National Science Foundation of Guangdong Province(000435)Research Foundation for the Doctoral Program of Higher Education of China(20010561003),Science and Technology Program of Guangzhou(2001J1-C0211)
文摘The catalytic performances of methanol steam reforming reactions on CuZn(Zr)AIO catalysts were studied. When the ZrO2 promoter was added to a CuZnAIO catalyst, its methanol conversion, H2 production and H2 selectivity improved greatly. By using the (?)COPZr-2 catalyst as an example, which exhibited the best catalytic performance, the optimized reaction conditions were established to be: 250℃, 0.1 MPa, H2O/MeOH=1.3, WHSV=3.56 h-1, and without carrier gas. A 150 h stability test of the (?)COPZr-2 catalyst showed that the catalyst had good stability, as the methanol conversion and H2 production could be kept at 88% and 83% respectively. Moreover, outlet H2 and CO contents were>63% and 0.20%-0.31%, respectively.
基金Financial support from Guangdong Provincial Natural Science Foundation of China (000435), the Doctoral Program Foun- dation of the Ministry of Education (20010561003) Guangzhou Municipal Science and Technology project (2001J1-C0211).
文摘Cu/ZnAlO catalysts derived from hydroxycarbonate precursors containinghydrotalcite-like layered double hydroxides (LDHs) were studied. The influence on the performanceof the catalysts was also studied when the Al in the Cu/ZnAlO catalyst was partly or completelyreplaced by Zr or Ce.
基金supported by the Natural Science Fundation of Fujian Province of China (No. 2017J06015)the Foundation of Public Welfare Research and Capacity Building in Guangdong Province (No. 2014A010106002)+2 种基金the State Key Laboratory of Catalytic Materials and Reaction Engineering (RIPP, SINOPEC) under Project No. 33600000-15-ZC06070004the supports from the Fundamental Research Funds for Central Universities, the Xiamen University (No. 20720160079)the Collaborative Innovation Center of HighEnd Equipment Manufacturing in Fujian are also acknowledged
文摘In this study, the laminated porous metal fiber sintered felt(PMFSF) functioning as catalyst support was used in a cylindrical methanol steam reforming(MSR) microreactor for hydrogen production. The PMFSF was fabricated by the low temperature solid-phase sintering method using metal fibers such as copper fibers and aluminum fibers which are obtained by the multi-tooth cutting method. The two-layer impregnation method was employed to coat Cu/Zn/Al/Zr catalyst on the PMFSF. The effect of fiber material, uniform porosity and gradient porosity on the performance of methano steam reforming microreactor was studied by varying the gas hourly space velocity(GHSV) and reaction temperature. Our results showed that the loading strength of porous copper fiber sintered felt(PCFSF) was better than porous aluminum fiber sintered felt(PAFSF). Under the same reaction conditions, the PCFSF showed higher methanol conversion and more H_2 output than PAFSF. Moreover, the gradient porosity(Type 5: 90%×80%×70%) of PMFSF used as the catalyst support in microreactor demonstrated a best reaction performance for hydrogen production.
基金Natural Science Foundation of Zhejiang Province (LQ21B060007)。
文摘Methanol steam reforming(MSR) is an attractive approach to produce hydrogen for fuel cells.Due to the limited catalyst loading volume and frequent start-ups and shut-downs on board,it is highly desired to develop an extremely active and robust catalyst.Herein,on the basis of industrial Cu/ZnO/Al_(2) O_(3) catalysts,a series of CuZnAl-xMg catalysts with enhanced Cu-ZnO synergy were synthesized via magnesium assisted strategy.The incorporation of magnesium was found to be beneficial to the enhancement of catalytic activity and stability of catalyst.A combination of complementa ry characterizations(e.g.XRD,H_(2)-TPR,N_(2) O chemisorption,TEM,XPS analysis etc.) proves that isomorphous substitution of Cu^(2+)in malachite phase gives rise to more dispersive Cu and ZnO NPs,and the increased Cu^(+)/Cu~0 ratio indicates the strengthened Cu-ZnO synergy effect,which leads to the boosted stability during the thermal treatment.
文摘In this study, the catalyst composition in binary ZnO-Al<sub>2</sub>O<sub>3</sub> catalyst was initially evaluated and optimized for methanol steam reforming. Then different Na contents were loaded by an incipient wetness impregnation method onto the optimized ZnAl catalyst. It was found that the activity was greatly enhanced by the modification of Na, which depended on the Na content in the catalyst. The methanol conversion was 96% on a 0.1 Na/0.4 ZnAl catalyst (GHSV = 14,040 h<sup>-</sup><sup>1</sup>, S/C = 1.4, 350°C), which was much higher with respect to a Na-free 0.4 ZnAl catalyst (74%). The remarkable improvement of activity was attributed to a weakening of the C-H bonds and clear of hydroxyl group by the Na dopant leading to an accelerated dehydrogenation of the reaction intermediates formed on ZnAl<sub>2</sub>O<sub>4</sub> spinel surface and thus the overall reaction.
基金supported by the Iran National Science Foundation (INSF)
文摘A novel design of plate-type microchannel reactor has been developed for fuel cell-grade hydrogen production.Commercial Cu/Zn/Al2O3 was used as catalyst for the reforming reaction,and its effectiveness was evaluated on the mole fraction of products,methanol conversion,hydrogen yield and the amount of carbon monoxide under various operating conditions.Subsequently,0.5 wt% Ru/Al2O3 as methanation catalyst was prepared by impregnation method and coupled with MSR step to evaluate the capability of methanol processor for CO reduction.Based on the experimental results,the optimum conditions were obtained as feed flow rate of 5mL/h and temperature of 250℃,leading to a low CO selectivity and high H2 yield.The designed reformer with catalyst coated layer was compared with the conventional packed bed reformer at the same operating conditions.The constructed fuel processor had a good performance and excellent capability for on-board hydrogen production.
基金supported by the Youth Innovation Promotion Association of Chinese Academy of Sciencesthe Key Technical Personnel of Chinese Academy of Sciences+1 种基金the STS Program of Chinese Academy of Sciences (No. KFJJ-STS-SCYD-302)the National Natural Science Foundation of China (22108288)。
文摘The on-board methanol steam reforming(MSR) has long been considered as an effective approach to insitu produce hydrogen for fuel cell vehicles(FCVs). However, the conventional MSR catalyst pellets suffer from easy breakage during the vehicle movement, leading to increased pressure drop and reduced system stability. Herein, we introduce an integrated method to prepare the highly controlled structured catalysts based on coupled processes: direct prototyping the structured substrate using digital light processing(DLP) 3D printing technology, in-situ dynamic crystallization of active components assisted by magnetic resonance imaging(MRI) and calcination. The synthesized catalyst owns a gradient layer of active component, and exhibits better MSR performance, higher mechanical strength, reduced pressure drop, higher Cu dispersion and better adhesion of active compounds when compared with the conventional powder and pellet catalysts. The demonstrated successful application proves the feasibility of developed method,which has great potential to be used for preparing precisely other monolithic catalysts with customized structures.