With growing demand for propylene and increasing production of propane from shale gas,the technologies of propylene production,including direct dehydrogenation and oxidative dehydrogenation of propane,have drawn great...With growing demand for propylene and increasing production of propane from shale gas,the technologies of propylene production,including direct dehydrogenation and oxidative dehydrogenation of propane,have drawn great attention in recent years.In particular,direct dehydrogenation of propane to propylene is regarded as one of the most promising methods of propylene production because it is an on-purpose technique that exclusively yields propylene instead of a mixture of products.In this critical review,we provide the current investigations on the heterogeneous catalysts(such as Pt,CrOx,VOx,GaOx-based catalysts,and nanocarbons)used in the direct dehydrogenation of propane to propylene.A detailed comparison and discussion of the active sites,catalytic mechanisms,influencing factors(such as the structures,dispersions,and reducibilities of the catalysts and promoters),and supports for different types of catalysts is presented.Furthermore,rational designs and preparation of high-performance catalysts for propane dehydrogenation are proposed and discussed.展开更多
Uniform-uispersed Ni nanoparticics(NPs)anchored on reduced graphene oxide(Ni@rGO)catalyzed MgH2(MH-Ni@rGO)has been fabricated by mechanical milling.The effects of milling time and Ni loading amount on the hydrogen sto...Uniform-uispersed Ni nanoparticics(NPs)anchored on reduced graphene oxide(Ni@rGO)catalyzed MgH2(MH-Ni@rGO)has been fabricated by mechanical milling.The effects of milling time and Ni loading amount on the hydrogen storage properties of MgH2 have been investigated.The initial hydrogen desorption temperature of MgH2 catalyzed by 10 wt.%Ni4@rGO6 for milling 5 h is significantly decreased from 251℃ to 190℃.The composite can absorb 5.0 wt.%hydrogen in 20 min at 100℃,while it can desorb 6.1 wt.%within 15 min at 300℃.Through the investigation of the phase transformation and dehydrogenation kinetics during hydrogen ab/desorption cycles,we found that the in-situ formed Mg2Ni/Mg2NiH4 exhibited better catalytic effect than Ni.When Ni loading amount is 45 wt.%,the rGO in Ni@rGO catalysts can prevent the reaction of Ni and Mg due to the strong interaction between rGO and Ni NPs.展开更多
Dehydrogenation of ethylbenzene （EB） to styrene （ST） in the presence of CO2, in which EB dehydrogenation is coupled with the reverse water-gas shift （RWGS）, was investigated extensively through both theoretical ...Dehydrogenation of ethylbenzene （EB） to styrene （ST） in the presence of CO2, in which EB dehydrogenation is coupled with the reverse water-gas shift （RWGS）, was investigated extensively through both theoretical analysis and experimental characterization. The reaction coupling proved to be superior to the single dehydrogenation in several respects. Thermodynamic analysis suggests that equilibrium conversion of EB can be improved greatly by reaction coupling due to the simultaneous elimination of the hydrogen produced from dehydrogenation. Catalytic tests proved that iron and vanadium supported on activated carbon or Al2O3 with certain promoters are potential catalysts for this coupling process. The catalysts of iron and vanadium are different in the reaction mechanism, although ST yield is always associated with CO2 conversion over various catalysts. The two-step pathway plays an important role in the coupling process over Fe/Al2O3, while the one-step pathway dominates the reaction over V/Al2O3. Coke deposition and deep reduction of active components are the major causes of catalyst deactivation. CO2 can alleviate the catalyst deactivation effectively through preserving the active species at high valence in the coupling process, though it can not suppress the coke deposition.展开更多
基金supported by the National Natural Science Foundation of China(21421001,21573115)the Fundamental Research Funds for the Central Universities(63185015)the Foundation of State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering(2017-K13)~~
文摘With growing demand for propylene and increasing production of propane from shale gas,the technologies of propylene production,including direct dehydrogenation and oxidative dehydrogenation of propane,have drawn great attention in recent years.In particular,direct dehydrogenation of propane to propylene is regarded as one of the most promising methods of propylene production because it is an on-purpose technique that exclusively yields propylene instead of a mixture of products.In this critical review,we provide the current investigations on the heterogeneous catalysts(such as Pt,CrOx,VOx,GaOx-based catalysts,and nanocarbons)used in the direct dehydrogenation of propane to propylene.A detailed comparison and discussion of the active sites,catalytic mechanisms,influencing factors(such as the structures,dispersions,and reducibilities of the catalysts and promoters),and supports for different types of catalysts is presented.Furthermore,rational designs and preparation of high-performance catalysts for propane dehydrogenation are proposed and discussed.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51671118)the research grant(No.16520721800 and No.19ZR1418400)from Science and Technology Commission of Shanghai Municipality.The authors gratefully acknowledge support for materials analysis and research from Instrumental Analysis and Research Center of Shanghai University.
文摘Uniform-uispersed Ni nanoparticics(NPs)anchored on reduced graphene oxide(Ni@rGO)catalyzed MgH2(MH-Ni@rGO)has been fabricated by mechanical milling.The effects of milling time and Ni loading amount on the hydrogen storage properties of MgH2 have been investigated.The initial hydrogen desorption temperature of MgH2 catalyzed by 10 wt.%Ni4@rGO6 for milling 5 h is significantly decreased from 251℃ to 190℃.The composite can absorb 5.0 wt.%hydrogen in 20 min at 100℃,while it can desorb 6.1 wt.%within 15 min at 300℃.Through the investigation of the phase transformation and dehydrogenation kinetics during hydrogen ab/desorption cycles,we found that the in-situ formed Mg2Ni/Mg2NiH4 exhibited better catalytic effect than Ni.When Ni loading amount is 45 wt.%,the rGO in Ni@rGO catalysts can prevent the reaction of Ni and Mg due to the strong interaction between rGO and Ni NPs.
基金The authors are grateful for the financial support of The Sate Key Fundamental Research Project and the Natural Science Foundation of China.
文摘Dehydrogenation of ethylbenzene （EB） to styrene （ST） in the presence of CO2, in which EB dehydrogenation is coupled with the reverse water-gas shift （RWGS）, was investigated extensively through both theoretical analysis and experimental characterization. The reaction coupling proved to be superior to the single dehydrogenation in several respects. Thermodynamic analysis suggests that equilibrium conversion of EB can be improved greatly by reaction coupling due to the simultaneous elimination of the hydrogen produced from dehydrogenation. Catalytic tests proved that iron and vanadium supported on activated carbon or Al2O3 with certain promoters are potential catalysts for this coupling process. The catalysts of iron and vanadium are different in the reaction mechanism, although ST yield is always associated with CO2 conversion over various catalysts. The two-step pathway plays an important role in the coupling process over Fe/Al2O3, while the one-step pathway dominates the reaction over V/Al2O3. Coke deposition and deep reduction of active components are the major causes of catalyst deactivation. CO2 can alleviate the catalyst deactivation effectively through preserving the active species at high valence in the coupling process, though it can not suppress the coke deposition.
