A physical mixture of alkali-promoted iron catalyst with binder based on Fischer-Tropsch synthesis and an acidic co-catalyst （HZSM5） for syngas conversion to hydrocarbons was studied in a fixed bed micro reactor. De...A physical mixture of alkali-promoted iron catalyst with binder based on Fischer-Tropsch synthesis and an acidic co-catalyst （HZSM5） for syngas conversion to hydrocarbons was studied in a fixed bed micro reactor. Deactivation data were obtained during the synthesis over a 1400 h period. The deactivation studies on iron catalyst showed that this trend followed the phase transformation Fe2.2C （ ε′） → Fe5C2 （χ） → Fe3C （θ）, and the final predominant phase of the catalyst was Fe3C （θ）. Deactivation of zeolite component in bifunctional catalyst may be caused by coking over the zeolitic component, dealumination of zeolite crystals, and migration of alkali promoters from iron catalyst under synthesis conditions. The deactivation rate of iron catalyst was also obtained.展开更多
采用水热合成法制备核壳结构Zn/HZSM-5_((Si/Al=25))@HZSM-5_((Si/Al=200))催化剂,并考察其甲醇制芳烃(Methanol to Aromatics,MTA)反应性能,重点研究壳层包覆对催化剂积碳行为及催化寿命的影响。结果表明,高Si/Al壳层催化剂其低酸量可...采用水热合成法制备核壳结构Zn/HZSM-5_((Si/Al=25))@HZSM-5_((Si/Al=200))催化剂,并考察其甲醇制芳烃(Methanol to Aromatics,MTA)反应性能,重点研究壳层包覆对催化剂积碳行为及催化寿命的影响。结果表明,高Si/Al壳层催化剂其低酸量可抑制含氧积碳生成;壳层对核层的包覆作用可从根本上阻断核层催化剂上含氧积碳的生成;核壳结构的构筑可调变催化剂积碳行为,催化剂失活速率降低,催化稳定性和芳构化性能明显增强,在反应温度T=400℃,甲醇空速WHSV=1.2 h^(-1)的反应条件下,Zn/HZSM-5@HZSM-5核壳催化剂的催化寿命达210 h,起始轻质芳烃(BTX)选择性达46.2%且反应138 h后仍高达20%以上。展开更多
SAPO-5 zeolite supported RuMn was a highly efficient catalyst for the aqueous-phase selective hydrodeoxygenation of guaiacol to cyclohexanol.The optimal catalyst achieved a high cyclohexanol yield of 93.7%at full guai...SAPO-5 zeolite supported RuMn was a highly efficient catalyst for the aqueous-phase selective hydrodeoxygenation of guaiacol to cyclohexanol.The optimal catalyst achieved a high cyclohexanol yield of 93.7%at full guaiacol conversion under mild conditions,with a high TOF of 920 h^(-1).Moreover,the catalyst displayed remarkable performance for the hydrogenation of phenol to cyclohexanol,where a 100%yield of cyclohexanol was obtained at a phenol-to-Ru molar ratio of about 17900.In particular,the catalyst exhibited excellent recyclability and could be recycled for 20 times without obvious activity loss.The as-prepared RuMn/SAPO-5 catalyst exhibited higher performance than most of the reported Rubased catalysts.展开更多
5-Hydroxymethylfurfural(HMF)and its oxidation derivatives have emerged as a bridge between biomass resources and the future energy industry.These renewable biomass resources can be transformed into a variety of value-...5-Hydroxymethylfurfural(HMF)and its oxidation derivatives have emerged as a bridge between biomass resources and the future energy industry.These renewable biomass resources can be transformed into a variety of value-added chemicals,thereby addressing the challenges posed by diminishing fossil fuel reserves and environmental concerns.The immobilization of catalysts represents an innovative method for the sustainable and efficient synthesis of HMF and its oxidation derivatives.This method not only enhances the yield and selectivity of the products but also allows for the optimization of the catalytic performance of immobilized catalysts through the strategic design of their supports.In this review,we provide an overview of the recent advancements in the technology of immobilized catalyst and its application in the synthesis of HMF and its oxidation derivatives,with a particular focus on the preparation and catalytic characteristics of these immobilized catalysts.Furthermore,we discuss potential future directions for the development of immobilized catalysts,including the preparation of high-performance immobilized catalysts,the exploration of their growth and catalytic mechanisms,and the economic implications of raw material utilization.This area of research presents both significant promise and considerable challenges.展开更多
Developing biomass platform compounds into high value-added chemicals is a key step in renewable resource utilization.Herein,we report porous carbon-supported Ni-ZnO nanoparticles catalyst(Ni-ZnO/AC)synthesized via lo...Developing biomass platform compounds into high value-added chemicals is a key step in renewable resource utilization.Herein,we report porous carbon-supported Ni-ZnO nanoparticles catalyst(Ni-ZnO/AC)synthesized via low-temperature coprecipitation,exhibiting excellent performance for the selective hydrogenation of 5-hydroxymethylfurfural(HMF).A linear correlation is first observed between solvent polarity(E_(T)(30))and product selectivity within both polar aprotic and protic solvent classes,suggesting that solvent properties play a vital role in directing reaction pathways.Among these,1,4-dioxane(aprotic)favors the formation of 2,5-bis(hydroxymethyl)furan(BHMF)with 97.5%selectivity,while isopropanol(iPrOH,protic)promotes 2,5-dimethylfuran production with up to 99.5%selectivity.Mechanistic investigations further reveal that beyond polarity,proton-donating ability is critical in facilitating hydrodeoxygenation.iPrOH enables a hydrogen shuttle mechanism where protons assist in hydroxyl group removal,lowering the activation barrier.In contrast,1,4-dioxane,lacking hydrogen bond donors,stabilizes BHMF and hinders further conversion.Density functional theory calculations confirm a lower activation energy in iPrOH(0.60 eV)compared to 1,4-dioxane(1.07 eV).This work offers mechanistic insights and a practical strategy for solvent-mediated control of product selectivity in biomass hydrogenation,highlighting the decisive role of solvent-catalyst-substrate interactions.展开更多
Cu nanoparticles supported on a variety of oxide supports, including SiO2, TiO2, ZrO2, Al2O3, MgO and ZnO, were investigated for the hydrogenolysis of biomass‐derived furfuryl alcohol to1,2‐pentanediol and 1,5‐pent...Cu nanoparticles supported on a variety of oxide supports, including SiO2, TiO2, ZrO2, Al2O3, MgO and ZnO, were investigated for the hydrogenolysis of biomass‐derived furfuryl alcohol to1,2‐pentanediol and 1,5‐pentanediol. A Cu‐Al2O3 catalyst with 10 wt% Cu loading prepared by a co‐precipitation method exhibited the best performance in terms of producing pentanediols compared with the other materials. This catalyst generated an 85.8% conversion and a 70.3% combined selectivity for the target pentanediols at 413 K and 8 MPa H2 over an 8‐h reaction. The catalyst could also be recycled over repeated reaction trials without any significant decrease in productivity. Characterizations with X‐ray diffraction, NH3/CO2‐temperature programmed desorption, N2 adsorption,transmission electron microscopy and N2 O chemisorption demonstrated that intimate and effective interactions between Cu particles and the acidic Al2O3 support in this material greatly enhanced its activity and selectivity. The promotion of the hydrogenolysis reaction was found to be especially sensitive to the Cu particle size, and the catalyst with Cu particles 1.9 to 2.4 nm in size showed the highest turnover frequency during the synthesis of pentanediols.展开更多
A titania support with a large surface area was developed, which has a BET surface area of 380.5 m^2/g, four times that of a traditional titania support. The support was ultrasonically impregnated with 5 wt% vanadia. ...A titania support with a large surface area was developed, which has a BET surface area of 380.5 m^2/g, four times that of a traditional titania support. The support was ultrasonically impregnated with 5 wt% vanadia. A special heat treatment was used in the calcination to maintain the large surface area and high dispersion of vanadium species. This catalyst was compared to a common V2O5-TiO2 catalyst with the same vanadia loading prepared by a traditional method. The new catalyst has a surface area of 117.7 m^2/g, which was 38% higher than the traditional V2O5-TiO2 catalyst. The selective catalytic reduction（SCR） performance demonstrated that the new catalyst had a wider temperature window and better N2 selectivity compared to the traditional one. The NO conversion was 80% from 200 to 450 °C. The temperature window was 100 °C wider than the traditional catalyst. Raman spectra indicated that the vanadium species formed more V-O-V linkages on the catalyst prepared by the traditional method. The amount of V-O-Ti and V=O was larger for the new catalyst. Temperature programmed desorption of NH3, temperature programmed reduction by H2 and X-ray photoelectron spectroscopy results showed that its redox ability and total acidity were enhanced. The results are helpful for developing a more efficient SCR catalyst for the removal of NOx in flue gases.展开更多
文摘A physical mixture of alkali-promoted iron catalyst with binder based on Fischer-Tropsch synthesis and an acidic co-catalyst （HZSM5） for syngas conversion to hydrocarbons was studied in a fixed bed micro reactor. Deactivation data were obtained during the synthesis over a 1400 h period. The deactivation studies on iron catalyst showed that this trend followed the phase transformation Fe2.2C （ ε′） → Fe5C2 （χ） → Fe3C （θ）, and the final predominant phase of the catalyst was Fe3C （θ）. Deactivation of zeolite component in bifunctional catalyst may be caused by coking over the zeolitic component, dealumination of zeolite crystals, and migration of alkali promoters from iron catalyst under synthesis conditions. The deactivation rate of iron catalyst was also obtained.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(LY23B060006 and LY18B060016).
文摘SAPO-5 zeolite supported RuMn was a highly efficient catalyst for the aqueous-phase selective hydrodeoxygenation of guaiacol to cyclohexanol.The optimal catalyst achieved a high cyclohexanol yield of 93.7%at full guaiacol conversion under mild conditions,with a high TOF of 920 h^(-1).Moreover,the catalyst displayed remarkable performance for the hydrogenation of phenol to cyclohexanol,where a 100%yield of cyclohexanol was obtained at a phenol-to-Ru molar ratio of about 17900.In particular,the catalyst exhibited excellent recyclability and could be recycled for 20 times without obvious activity loss.The as-prepared RuMn/SAPO-5 catalyst exhibited higher performance than most of the reported Rubased catalysts.
文摘5-Hydroxymethylfurfural(HMF)and its oxidation derivatives have emerged as a bridge between biomass resources and the future energy industry.These renewable biomass resources can be transformed into a variety of value-added chemicals,thereby addressing the challenges posed by diminishing fossil fuel reserves and environmental concerns.The immobilization of catalysts represents an innovative method for the sustainable and efficient synthesis of HMF and its oxidation derivatives.This method not only enhances the yield and selectivity of the products but also allows for the optimization of the catalytic performance of immobilized catalysts through the strategic design of their supports.In this review,we provide an overview of the recent advancements in the technology of immobilized catalyst and its application in the synthesis of HMF and its oxidation derivatives,with a particular focus on the preparation and catalytic characteristics of these immobilized catalysts.Furthermore,we discuss potential future directions for the development of immobilized catalysts,including the preparation of high-performance immobilized catalysts,the exploration of their growth and catalytic mechanisms,and the economic implications of raw material utilization.This area of research presents both significant promise and considerable challenges.
基金the National Nature Science Foundation of China for Excellent Young Scientists Fund(32222058)Fundamental Research Foundation of CAF(CAFYBB2022QB001).
文摘Developing biomass platform compounds into high value-added chemicals is a key step in renewable resource utilization.Herein,we report porous carbon-supported Ni-ZnO nanoparticles catalyst(Ni-ZnO/AC)synthesized via low-temperature coprecipitation,exhibiting excellent performance for the selective hydrogenation of 5-hydroxymethylfurfural(HMF).A linear correlation is first observed between solvent polarity(E_(T)(30))and product selectivity within both polar aprotic and protic solvent classes,suggesting that solvent properties play a vital role in directing reaction pathways.Among these,1,4-dioxane(aprotic)favors the formation of 2,5-bis(hydroxymethyl)furan(BHMF)with 97.5%selectivity,while isopropanol(iPrOH,protic)promotes 2,5-dimethylfuran production with up to 99.5%selectivity.Mechanistic investigations further reveal that beyond polarity,proton-donating ability is critical in facilitating hydrodeoxygenation.iPrOH enables a hydrogen shuttle mechanism where protons assist in hydroxyl group removal,lowering the activation barrier.In contrast,1,4-dioxane,lacking hydrogen bond donors,stabilizes BHMF and hinders further conversion.Density functional theory calculations confirm a lower activation energy in iPrOH(0.60 eV)compared to 1,4-dioxane(1.07 eV).This work offers mechanistic insights and a practical strategy for solvent-mediated control of product selectivity in biomass hydrogenation,highlighting the decisive role of solvent-catalyst-substrate interactions.
基金supported by the National Natural Science Foundation of China(2113301121203221+1 种基金21473224)the Natural Science Foundation of Gansu Province(1308RJZA281)~~
文摘Cu nanoparticles supported on a variety of oxide supports, including SiO2, TiO2, ZrO2, Al2O3, MgO and ZnO, were investigated for the hydrogenolysis of biomass‐derived furfuryl alcohol to1,2‐pentanediol and 1,5‐pentanediol. A Cu‐Al2O3 catalyst with 10 wt% Cu loading prepared by a co‐precipitation method exhibited the best performance in terms of producing pentanediols compared with the other materials. This catalyst generated an 85.8% conversion and a 70.3% combined selectivity for the target pentanediols at 413 K and 8 MPa H2 over an 8‐h reaction. The catalyst could also be recycled over repeated reaction trials without any significant decrease in productivity. Characterizations with X‐ray diffraction, NH3/CO2‐temperature programmed desorption, N2 adsorption,transmission electron microscopy and N2 O chemisorption demonstrated that intimate and effective interactions between Cu particles and the acidic Al2O3 support in this material greatly enhanced its activity and selectivity. The promotion of the hydrogenolysis reaction was found to be especially sensitive to the Cu particle size, and the catalyst with Cu particles 1.9 to 2.4 nm in size showed the highest turnover frequency during the synthesis of pentanediols.
基金supported by the National Natural Science Foundation of China(21325731,21221004)the National High Technology Research and Development Program of China(863 Program)the State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex
文摘A titania support with a large surface area was developed, which has a BET surface area of 380.5 m^2/g, four times that of a traditional titania support. The support was ultrasonically impregnated with 5 wt% vanadia. A special heat treatment was used in the calcination to maintain the large surface area and high dispersion of vanadium species. This catalyst was compared to a common V2O5-TiO2 catalyst with the same vanadia loading prepared by a traditional method. The new catalyst has a surface area of 117.7 m^2/g, which was 38% higher than the traditional V2O5-TiO2 catalyst. The selective catalytic reduction（SCR） performance demonstrated that the new catalyst had a wider temperature window and better N2 selectivity compared to the traditional one. The NO conversion was 80% from 200 to 450 °C. The temperature window was 100 °C wider than the traditional catalyst. Raman spectra indicated that the vanadium species formed more V-O-V linkages on the catalyst prepared by the traditional method. The amount of V-O-Ti and V=O was larger for the new catalyst. Temperature programmed desorption of NH3, temperature programmed reduction by H2 and X-ray photoelectron spectroscopy results showed that its redox ability and total acidity were enhanced. The results are helpful for developing a more efficient SCR catalyst for the removal of NOx in flue gases.
