Ecological efficiency is a crucial index to evaluate the green development of freshwater aquaculture industry,which is an important factor for its rapid and sustainable development.Taking the Yangtze River Economic Be...Ecological efficiency is a crucial index to evaluate the green development of freshwater aquaculture industry,which is an important factor for its rapid and sustainable development.Taking the Yangtze River Economic Belt from 2014 to 2022 as an example,the Super-NSBM model was used to estimate the freshwater aquaculture's ecological efficiency and phased efficiency.The influence mechanism of freshwater aquacultural ecological efficiency was investigated by the Tobit model.Then,the dynamic evolution of the total factor productivity was analyzed by the super-efficiency SBM-Malmquist index.The results showed that:(1)During the study period,the average ecological efficiency of freshwater aquaculture in the Yangtze River Economic Belt was greater than 1,beyond the valid value.Respectively,showing upper stream>middle stream>down-stream;In terms of stages,the efficiency in the first stage is generally higher than that in the second stage.(2)From the dynamic perspective of efficiency,the total factor productivity of freshwater aquaculture is more influenced by the efficiency of technological progress.(3)From the perspective of influencing factors,the structural adjustment of aquaculture,the degree of marketization and the level of economic development impact positively the ecological efficiency and phased efficiency of freshwater aquaculture,while the disaster rate has a negative effect on both of them;Training intensity has an adverse influence on the first stage.展开更多
This Highlight is inspired by a recent article in Science in which Gong and co-workers from Tianjin University reported a discovery of defective TiOx overlayers on metallic Ni nanoparticles induced by strong metal-sup...This Highlight is inspired by a recent article in Science in which Gong and co-workers from Tianjin University reported a discovery of defective TiOx overlayers on metallic Ni nanoparticles induced by strong metal-support interaction and their applications in propane dehydrogenation reaction[1].This work represents a conceptual innovation in the design of sustainable catalysts with state-of-the-art efficiency for alkane dehydrogenation reactions based on ecofriendly metal oxides and non-noble metals.Propane dehydrogenation(PDH)is a reaction of industrially relevance for on-purpose propylene production in the context of the shale gas revolution and the steady growth of the world’s demand on propylene[2].Currently,the commercial PDH processes are achieved with supported Pt or CrOx catalysts,which either rely on the use of noble or toxic metals.As reflected in the rapidly increasing number of publications on PDH in recent years,numerous types of catalysts have been developed to improve the activities or stabilities of the metal active sites.展开更多
1 Introduction Aromatics(mainly benzene,toluene,and xylenes,BTX)are essential intermediates in the chemical industry.They are employed in the synthesis of a broad spectrum of chemicals and materials,e.g.,various polym...1 Introduction Aromatics(mainly benzene,toluene,and xylenes,BTX)are essential intermediates in the chemical industry.They are employed in the synthesis of a broad spectrum of chemicals and materials,e.g.,various polymers,plastics,resins,solvents,dyes,pharmaceuticals^([1]).The manufacturing pathway of BTX mainly includes petroleum reforming of naphtha,coal-to-aromatics,methanol-to-aromatics^([2]).展开更多
1 Introduction.Carbon materials are ideal catalyst supports for functional metal components due to their appropriate physicochemical characteristics,such as high surface areas,tunable pore structures,variable morpholo...1 Introduction.Carbon materials are ideal catalyst supports for functional metal components due to their appropriate physicochemical characteristics,such as high surface areas,tunable pore structures,variable morphologies and versatile surface properties based on chemical modifications,low cost and facile preparations from diverse precursors[1,2].展开更多
Long-chain alkanes are abundant feedstocks supplied by natural resources and chemical industry. Specially, normal long-chain alkanes are primary products from Fischer-Tropsch synthesis(FTS) process, which is an import...Long-chain alkanes are abundant feedstocks supplied by natural resources and chemical industry. Specially, normal long-chain alkanes are primary products from Fischer-Tropsch synthesis(FTS) process, which is an important route for the utilization of coal in China. Facing a shift of energy nexus towards sustainable society, the conversion of long-chain alkanes derived from coal into value-added products(such as alkenes and oxygenates) is of great importance for securing China’s energy supply and the role transition of the commercial FTS plants from fuel makers to chemical suppliers. Among the potential transformation routes,the direct dehydrogenation of long-chain alkanes into alkenes is an attractive and practical route, due to the broad applications of long-chain alkenes(especially the linear α-olefins). In this review, we will summary the key insights obtained from the literature on the dehydrogenation of light alkanes based on supported metal catalysts and the dehydrogenation of alkanes with homogeneous molecular catalysts and then discuss how to translate these lessons into the development of efficient catalysts and processes for the dehydrogenation of long-chain alkanes into long-chain alkenes.展开更多
Titanium dioxide is coated on the surface of MCM-41 wafer through the plasma enhanced chemical vapor deposition （PECVD） method using titanium isopropoxide （TTIP） as a precursor. Annealing temperature is a key fact...Titanium dioxide is coated on the surface of MCM-41 wafer through the plasma enhanced chemical vapor deposition （PECVD） method using titanium isopropoxide （TTIP） as a precursor. Annealing temperature is a key factor affecting crystal phase of titanium dioxide. It will transform an amorphous structure to a polycrystalline structure by increasing temperature. The optimum anatase phase of TiO2 which can acquire the best methanol conversion under UV-light irradiation is obtained under an annealing temperature of 700℃ for 2 h, substrate tem- perature of 500~C, 70 mL. min1 of oxygen flow rate, and 100W of plasma power. In addition, the films are composed of an anatase-rutile mixed phase, and the ratio of anatase to rutile varies with substrate temperature and oxygen flow rate. The particle sizes of titanium dioxide are between 30.3 nm and 59.9nm by the calculation of Scherrer equation. Under the reaction conditions of ll6.8mg.L-1 methanol, 2.9mg.L-1 moisture, and 75~C of reaction temperature, the best conversion of methanol with UV-light is 48.2% by using the anatase-rutile （91.3/ 8.7） mixed phase TiO2 in a batch reactor for 60 min. While under fluorescent light irradiation, the best photoactivity appears by using the anatase-rutile （55.4/44.6） mixed phase TiO2 with a conversion of 40.0%.展开更多
Tuning the structures of supported metal catalysts at the atomic level has always been a critical topic in heterogeneous catalysis because of their wide applications and complicated structures[1].In recent years,numer...Tuning the structures of supported metal catalysts at the atomic level has always been a critical topic in heterogeneous catalysis because of their wide applications and complicated structures[1].In recent years,numerous studies have shown the great potential in using the supported metal catalysts comprising atomically dispersed metal species for various reactions.展开更多
基金supported by the Major Social Science Projects in China(Evaluation of the Development Potential of the Deep Blue Fisheries Industry under Climate Change,No.21&ZD100)the China Modern Agricultural Industry Technology System Support Project(CARS-47-G29).
文摘Ecological efficiency is a crucial index to evaluate the green development of freshwater aquaculture industry,which is an important factor for its rapid and sustainable development.Taking the Yangtze River Economic Belt from 2014 to 2022 as an example,the Super-NSBM model was used to estimate the freshwater aquaculture's ecological efficiency and phased efficiency.The influence mechanism of freshwater aquacultural ecological efficiency was investigated by the Tobit model.Then,the dynamic evolution of the total factor productivity was analyzed by the super-efficiency SBM-Malmquist index.The results showed that:(1)During the study period,the average ecological efficiency of freshwater aquaculture in the Yangtze River Economic Belt was greater than 1,beyond the valid value.Respectively,showing upper stream>middle stream>down-stream;In terms of stages,the efficiency in the first stage is generally higher than that in the second stage.(2)From the dynamic perspective of efficiency,the total factor productivity of freshwater aquaculture is more influenced by the efficiency of technological progress.(3)From the perspective of influencing factors,the structural adjustment of aquaculture,the degree of marketization and the level of economic development impact positively the ecological efficiency and phased efficiency of freshwater aquaculture,while the disaster rate has a negative effect on both of them;Training intensity has an adverse influence on the first stage.
文摘This Highlight is inspired by a recent article in Science in which Gong and co-workers from Tianjin University reported a discovery of defective TiOx overlayers on metallic Ni nanoparticles induced by strong metal-support interaction and their applications in propane dehydrogenation reaction[1].This work represents a conceptual innovation in the design of sustainable catalysts with state-of-the-art efficiency for alkane dehydrogenation reactions based on ecofriendly metal oxides and non-noble metals.Propane dehydrogenation(PDH)is a reaction of industrially relevance for on-purpose propylene production in the context of the shale gas revolution and the steady growth of the world’s demand on propylene[2].Currently,the commercial PDH processes are achieved with supported Pt or CrOx catalysts,which either rely on the use of noble or toxic metals.As reflected in the rapidly increasing number of publications on PDH in recent years,numerous types of catalysts have been developed to improve the activities or stabilities of the metal active sites.
基金the support from Tsinghua University and China Petroleumthe support from the academician workstation of Petrochemical Research Institute,China Petroleum。
文摘1 Introduction Aromatics(mainly benzene,toluene,and xylenes,BTX)are essential intermediates in the chemical industry.They are employed in the synthesis of a broad spectrum of chemicals and materials,e.g.,various polymers,plastics,resins,solvents,dyes,pharmaceuticals^([1]).The manufacturing pathway of BTX mainly includes petroleum reforming of naphtha,coal-to-aromatics,methanol-to-aromatics^([2]).
基金supported by the Ministry of Science and Technology of China(2021YFB4000205)the financial support from the Tsinghua University Dushi Program(20231080010)the State Key Laboratory of Catalytic Materials and Reaction Engineering。
文摘1 Introduction.Carbon materials are ideal catalyst supports for functional metal components due to their appropriate physicochemical characteristics,such as high surface areas,tunable pore structures,variable morphologies and versatile surface properties based on chemical modifications,low cost and facile preparations from diverse precursors[1,2].
基金supported by Tsinghua University(Initiative Scientific Research Program 20211080079)the National Natural Science Foundation of China(21972161,22172186)+7 种基金Chinese Academy of Sciences(CAS)Pioneer Talents Program(2018-095)Shanxi Talent Program(2019SBRJH01)Autonomous Research Project of State Key Laboratory of Coal Conversion(SKLCC)(2020BWZ006,2021BWZ007)Institute of Coal Chemistry(ICC)Innovation Fund(SCJJ-2020-02)Inner Mengolia Science&Technology Project Plan(2021GG0311)Major science and technology project of Ordos(2022EEDSKJZDZX001)Start-Up Grant of Institute of Coal Chemistry(2020SC001)Synfuels China Co.,Ltd.
文摘Long-chain alkanes are abundant feedstocks supplied by natural resources and chemical industry. Specially, normal long-chain alkanes are primary products from Fischer-Tropsch synthesis(FTS) process, which is an important route for the utilization of coal in China. Facing a shift of energy nexus towards sustainable society, the conversion of long-chain alkanes derived from coal into value-added products(such as alkenes and oxygenates) is of great importance for securing China’s energy supply and the role transition of the commercial FTS plants from fuel makers to chemical suppliers. Among the potential transformation routes,the direct dehydrogenation of long-chain alkanes into alkenes is an attractive and practical route, due to the broad applications of long-chain alkenes(especially the linear α-olefins). In this review, we will summary the key insights obtained from the literature on the dehydrogenation of light alkanes based on supported metal catalysts and the dehydrogenation of alkanes with homogeneous molecular catalysts and then discuss how to translate these lessons into the development of efficient catalysts and processes for the dehydrogenation of long-chain alkanes into long-chain alkenes.
文摘Titanium dioxide is coated on the surface of MCM-41 wafer through the plasma enhanced chemical vapor deposition （PECVD） method using titanium isopropoxide （TTIP） as a precursor. Annealing temperature is a key factor affecting crystal phase of titanium dioxide. It will transform an amorphous structure to a polycrystalline structure by increasing temperature. The optimum anatase phase of TiO2 which can acquire the best methanol conversion under UV-light irradiation is obtained under an annealing temperature of 700℃ for 2 h, substrate tem- perature of 500~C, 70 mL. min1 of oxygen flow rate, and 100W of plasma power. In addition, the films are composed of an anatase-rutile mixed phase, and the ratio of anatase to rutile varies with substrate temperature and oxygen flow rate. The particle sizes of titanium dioxide are between 30.3 nm and 59.9nm by the calculation of Scherrer equation. Under the reaction conditions of ll6.8mg.L-1 methanol, 2.9mg.L-1 moisture, and 75~C of reaction temperature, the best conversion of methanol with UV-light is 48.2% by using the anatase-rutile （91.3/ 8.7） mixed phase TiO2 in a batch reactor for 60 min. While under fluorescent light irradiation, the best photoactivity appears by using the anatase-rutile （55.4/44.6） mixed phase TiO2 with a conversion of 40.0%.
文摘Tuning the structures of supported metal catalysts at the atomic level has always been a critical topic in heterogeneous catalysis because of their wide applications and complicated structures[1].In recent years,numerous studies have shown the great potential in using the supported metal catalysts comprising atomically dispersed metal species for various reactions.
