The design of hollow mesoporous nanostructures for cascade catalytic reactions can inject new vitality into the development of nanostructures. In this study, we report a versatile cooperative template-directed coating...The design of hollow mesoporous nanostructures for cascade catalytic reactions can inject new vitality into the development of nanostructures. In this study, we report a versatile cooperative template-directed coating method for the synthesis of hollow and yolk-shell mesoporous zirconium titanium oxide nanospheres with varying compositions （ZrO2 content from 0 to 100%）, high surface areas （465 m2·g-1） and uniform mesopores. In particular, the hexadecylamine （HDA） used in the coating procedure serves as a soft template for silica@mesostructured metal oxide core-shell nanosphere formation. By a facile solvothermal treatment route with an ammonia solution and calcination in air, the silica@mesostructured zirconium titanium oxide spheres can be converted into highly uniform hollow zirconium titanium oxide spheres. By simply replacing hard template silica nanospheres with core-shell silica nanocomposites, the synthesis approach can be further used to prepare yolk-shell mesoporous structures through the coating and etching process. The approach is similar to the preparation of mesoporous silica nanocomposites from the self-assembly of the core, the soft template cetyltrimethylammonium bromide （CTAB） and a silica precursor and can be extended as a general method to coat mesoporous zirconium titanium oxide on other commonly used hard templates （e.g., mesoporous silica spheres, mesoporous organosilica ellipsoids, polymer spheres, and carbon nanospheres）. The presence of highly permeable mesoporous channels in the zirconium titanium oxide shells has been demonstrated by the reduction of 4-nitrophenol with yolk-shell Au@mesoporous zirconium titanium oxide as the catalyst. Moreover, a cascade catalytic reaction including an acid catalyzed step and a catalytic hydrogenation to afford benzimidazole derivatives can be carried out very effectively by using the accessible acidity of the yolk-shell structured mesoporous zirconium titanium oxide spheres containing a Pd core as a bifunctional catalyst, which mak展开更多
Li-O_(2)batteries are regarded as one of the most promising next-generation battery systems due to their high theoretical energy density,finding effective cathode catalysts with fine-tuned structure is a key way to im...Li-O_(2)batteries are regarded as one of the most promising next-generation battery systems due to their high theoretical energy density,finding effective cathode catalysts with fine-tuned structure is a key way to improve the performance.Herein,based on the structure of cubic zeolitic imidazolate framework-67(ZIF-67),a series of hollow catalysts were synthesized by different chemical etching treatments.Firstly,from the perspective of metal,nickel nitrate is used for etching,hollow Ni ZIF is obtained through Kirkendall effect.Secondly,hollow TA-ZIF is obtained by adding tannic acid to replace the methylimidazole ligand.Hollow structures have larger surface areas,materials can expose more active sites,which can lead to better performance of Li-O_(2)batteries.On this basis,having more oxygen vacancies can also improve the battery performance.At the same time,further loading noble metal ruthenium on the synthesized cobalt-based catalyst can effectively reduce the overpotential of Li-O_(2)battery and improve the battery performance.For TA-ZIF with more stable hollow structure and more oxygen vacancies,the cycle performance reaches 330 cycles after loading Ru.Compared with the 64 cycles of solid Co_(3)O_(4),it has a great improvement.展开更多
Metal oxide hollow structures are of great inter- est in many current and emerging areas of technology. This paper presents a facile and controlled protocol for the syn- thesis of Al-doped CeO2 hollow-shell spheres （...Metal oxide hollow structures are of great inter- est in many current and emerging areas of technology. This paper presents a facile and controlled protocol for the syn- thesis of Al-doped CeO2 hollow-shell spheres （CHS）, where the dopant confers enhanced stability and activity to the ma- terial. These Al-doped CeO2 hollow-shell spheres （ACHS） possess a controllable shell number of up to three, where the sizes of the exterior, middle, and interior spheres were about 250-100 nm,150-50 nm, and 40-10 nm, respectively, and the average shell thickness was -15 nm. The thermal stability of the ACHS structure was enhanced by the homogeneous in- corporation of AI atoms, and more active oxygen species were present compared with those in the non-doped congener. Au NPs supported on ACHS （Au/ACHS） showed superior cat- alytic performance for the reduction of p-nitrophenol. For the same Au NP content, the reaction rate constant （k） of the Au/ACHS was nearly twice that of the non-doped Au/CHS, indicating that AI doping is promising for improving the per- formance of inert or unstable oxides as catalyst supports.展开更多
The intrinsic poor electrical conductivity,severe dissolution of K x S y intermediates,and inferior conversion reaction reversibility extremely impede the practical application of the transition-metal chalcogenides(TM...The intrinsic poor electrical conductivity,severe dissolution of K x S y intermediates,and inferior conversion reaction reversibility extremely impede the practical application of the transition-metal chalcogenides(TMDs)anode for potassium-ion batteries(PIBs).Herein,a rationally designed Cu_(9)S_(5)/MoS_(2)/C heterostruc-ture hollow nanocage was synthesized with assistance from metal-organic frameworks(MOFs)precursor.During the K-storage process,the homogeneously distributed the sulfiphilic nature of Cu 0 reaction prod-uct could act as a dual-functional catalyst,not only facilitating the rapid charge transfer but also effec-tively anchoring(K x S y)polysulfides,thus boosting K-storage reactions reversibility during the conversion reaction process.When applied as an anode for PIBs,the as-prepared heterostructure exhibits excellent reversible capacity and long cycle lifespan(350.5 mAh g^(-1)at 0.1 A g^(-1)and 0.04%per cycle capacity de-cay at 1 A g^(-1)after 1000 cycles).Additionally,the potassium storage mechanism is distinctly revealed by in-situ characterizations.The nanoarchitecture designing strategy for the advanced electrode in this work could provide vital guidance for relevant energy storage materials.展开更多
基金This work was supported by the National Natural Science Foundation of China （Grant Nos. 21171064 and 21071059）.
文摘The design of hollow mesoporous nanostructures for cascade catalytic reactions can inject new vitality into the development of nanostructures. In this study, we report a versatile cooperative template-directed coating method for the synthesis of hollow and yolk-shell mesoporous zirconium titanium oxide nanospheres with varying compositions （ZrO2 content from 0 to 100%）, high surface areas （465 m2·g-1） and uniform mesopores. In particular, the hexadecylamine （HDA） used in the coating procedure serves as a soft template for silica@mesostructured metal oxide core-shell nanosphere formation. By a facile solvothermal treatment route with an ammonia solution and calcination in air, the silica@mesostructured zirconium titanium oxide spheres can be converted into highly uniform hollow zirconium titanium oxide spheres. By simply replacing hard template silica nanospheres with core-shell silica nanocomposites, the synthesis approach can be further used to prepare yolk-shell mesoporous structures through the coating and etching process. The approach is similar to the preparation of mesoporous silica nanocomposites from the self-assembly of the core, the soft template cetyltrimethylammonium bromide （CTAB） and a silica precursor and can be extended as a general method to coat mesoporous zirconium titanium oxide on other commonly used hard templates （e.g., mesoporous silica spheres, mesoporous organosilica ellipsoids, polymer spheres, and carbon nanospheres）. The presence of highly permeable mesoporous channels in the zirconium titanium oxide shells has been demonstrated by the reduction of 4-nitrophenol with yolk-shell Au@mesoporous zirconium titanium oxide as the catalyst. Moreover, a cascade catalytic reaction including an acid catalyzed step and a catalytic hydrogenation to afford benzimidazole derivatives can be carried out very effectively by using the accessible acidity of the yolk-shell structured mesoporous zirconium titanium oxide spheres containing a Pd core as a bifunctional catalyst, which mak
基金the National Natural Science Foundation of China(Nos.21606021 and 21771024).
文摘Li-O_(2)batteries are regarded as one of the most promising next-generation battery systems due to their high theoretical energy density,finding effective cathode catalysts with fine-tuned structure is a key way to improve the performance.Herein,based on the structure of cubic zeolitic imidazolate framework-67(ZIF-67),a series of hollow catalysts were synthesized by different chemical etching treatments.Firstly,from the perspective of metal,nickel nitrate is used for etching,hollow Ni ZIF is obtained through Kirkendall effect.Secondly,hollow TA-ZIF is obtained by adding tannic acid to replace the methylimidazole ligand.Hollow structures have larger surface areas,materials can expose more active sites,which can lead to better performance of Li-O_(2)batteries.On this basis,having more oxygen vacancies can also improve the battery performance.At the same time,further loading noble metal ruthenium on the synthesized cobalt-based catalyst can effectively reduce the overpotential of Li-O_(2)battery and improve the battery performance.For TA-ZIF with more stable hollow structure and more oxygen vacancies,the cycle performance reaches 330 cycles after loading Ru.Compared with the 64 cycles of solid Co_(3)O_(4),it has a great improvement.
基金financially supported by the National Natural Science Foundation of China (51472025 and 21671016)Beijing Nova Programme Interdisciplinary Cooperation Project
文摘Metal oxide hollow structures are of great inter- est in many current and emerging areas of technology. This paper presents a facile and controlled protocol for the syn- thesis of Al-doped CeO2 hollow-shell spheres （CHS）, where the dopant confers enhanced stability and activity to the ma- terial. These Al-doped CeO2 hollow-shell spheres （ACHS） possess a controllable shell number of up to three, where the sizes of the exterior, middle, and interior spheres were about 250-100 nm,150-50 nm, and 40-10 nm, respectively, and the average shell thickness was -15 nm. The thermal stability of the ACHS structure was enhanced by the homogeneous in- corporation of AI atoms, and more active oxygen species were present compared with those in the non-doped congener. Au NPs supported on ACHS （Au/ACHS） showed superior cat- alytic performance for the reduction of p-nitrophenol. For the same Au NP content, the reaction rate constant （k） of the Au/ACHS was nearly twice that of the non-doped Au/CHS, indicating that AI doping is promising for improving the per- formance of inert or unstable oxides as catalyst supports.
基金financially supported by the National Natural Science Foundation of China (Nos.52070194,52073309,51902347,and 51908555)the Natural Science Foundation of Hunan Province (Nos.2022JJ20069 and 2020JJ5741).
文摘The intrinsic poor electrical conductivity,severe dissolution of K x S y intermediates,and inferior conversion reaction reversibility extremely impede the practical application of the transition-metal chalcogenides(TMDs)anode for potassium-ion batteries(PIBs).Herein,a rationally designed Cu_(9)S_(5)/MoS_(2)/C heterostruc-ture hollow nanocage was synthesized with assistance from metal-organic frameworks(MOFs)precursor.During the K-storage process,the homogeneously distributed the sulfiphilic nature of Cu 0 reaction prod-uct could act as a dual-functional catalyst,not only facilitating the rapid charge transfer but also effec-tively anchoring(K x S y)polysulfides,thus boosting K-storage reactions reversibility during the conversion reaction process.When applied as an anode for PIBs,the as-prepared heterostructure exhibits excellent reversible capacity and long cycle lifespan(350.5 mAh g^(-1)at 0.1 A g^(-1)and 0.04%per cycle capacity de-cay at 1 A g^(-1)after 1000 cycles).Additionally,the potassium storage mechanism is distinctly revealed by in-situ characterizations.The nanoarchitecture designing strategy for the advanced electrode in this work could provide vital guidance for relevant energy storage materials.
