A2B2O7 pyrochlore is a kind of important functional materials for different purposes,which has been investigated extensively by crystallographers and material scientists.However,the catalytic chemistry of this type of...A2B2O7 pyrochlore is a kind of important functional materials for different purposes,which has been investigated extensively by crystallographers and material scientists.However,the catalytic chemistry of this type of special compounds has rarely been documented,though a few researchers have tried to synthesize some pyrochlore compounds with different chemical compositions for a variety of green energy production and air pollution control reactions in the history.With the expectation to help catalysis scientists to get better acquaintance with,and gain deeper understanding on this type of compounds as heterogeneous catalysts,the major publications over the past several decades have been screened and reviewed in this paper,based also on our own experience of studying on this type of catalytic materials.The crystalline phase transformations of the compounds with the change of the A and B site cations,the phase change’s influences on the surface and bulk properties,and their subsequent impact on the catalytic performance for different reactions have been summarized.Furthermore,the future work which needs to be performed to perceive in depth this kind of important materials as catalysts has been proposed and suggested.We trust that this short review contains valuable information,which will provide great help for people to get better cognition for A2 B2 O7 pyrochlore compounds,and assist them to develop better catalysts for various reactions.展开更多
A_2B_2O_7 system compounds, which usually present three phase structures mainly based on the ionic radius ratios of r_A and r_B(r_A/r_B), have been studied for potential applications in many fields, such as thermal ba...A_2B_2O_7 system compounds, which usually present three phase structures mainly based on the ionic radius ratios of r_A and r_B(r_A/r_B), have been studied for potential applications in many fields, such as thermal barrier coatings, luminescence powders, fast-ion conductors, photocatalysts, and matrices for immobilization of highly active radionuclides. Since 2005, La_2Hf_2O_7 was fabricated into transparent ceramics and much more attentions were paid on A_2B_2O_7 transparent ceramics for new applications. In this review, the development of A_2B_2O_7 system transparent ceramics was described. The structure characteristics, powder synthesis method, and sintering techniques of the final A_2B_2O_7 transparent ceramics were summarized. After that, the mostly reported A_2Hf_2O_7, A_2Zr_2O_7, and A_2Ti_2O_7 system transparent ceramics were systematically introduced. The potential application fields and future development trends were also discussed, focusing on scintillators, optical elements, and other luminescent materials.展开更多
基金Project supported by the National Natural Science Foundation of China(21962009,21567016,21666020)Natural Science Foundation of Jiangxi Province(20181ACB20005,20171BAB213013,20181BAB203017)Key Laboratory Foundation of Jiangxi Province for Environment and Energy Catalysis(20181BCD40004)。
文摘A2B2O7 pyrochlore is a kind of important functional materials for different purposes,which has been investigated extensively by crystallographers and material scientists.However,the catalytic chemistry of this type of special compounds has rarely been documented,though a few researchers have tried to synthesize some pyrochlore compounds with different chemical compositions for a variety of green energy production and air pollution control reactions in the history.With the expectation to help catalysis scientists to get better acquaintance with,and gain deeper understanding on this type of compounds as heterogeneous catalysts,the major publications over the past several decades have been screened and reviewed in this paper,based also on our own experience of studying on this type of catalytic materials.The crystalline phase transformations of the compounds with the change of the A and B site cations,the phase change’s influences on the surface and bulk properties,and their subsequent impact on the catalytic performance for different reactions have been summarized.Furthermore,the future work which needs to be performed to perceive in depth this kind of important materials as catalysts has been proposed and suggested.We trust that this short review contains valuable information,which will provide great help for people to get better cognition for A2 B2 O7 pyrochlore compounds,and assist them to develop better catalysts for various reactions.
基金financial supports from the National Key R&D Program of China (No.2017YFB0310500)the National Natural Science Foundation of China (No.51602326)
文摘A_2B_2O_7 system compounds, which usually present three phase structures mainly based on the ionic radius ratios of r_A and r_B(r_A/r_B), have been studied for potential applications in many fields, such as thermal barrier coatings, luminescence powders, fast-ion conductors, photocatalysts, and matrices for immobilization of highly active radionuclides. Since 2005, La_2Hf_2O_7 was fabricated into transparent ceramics and much more attentions were paid on A_2B_2O_7 transparent ceramics for new applications. In this review, the development of A_2B_2O_7 system transparent ceramics was described. The structure characteristics, powder synthesis method, and sintering techniques of the final A_2B_2O_7 transparent ceramics were summarized. After that, the mostly reported A_2Hf_2O_7, A_2Zr_2O_7, and A_2Ti_2O_7 system transparent ceramics were systematically introduced. The potential application fields and future development trends were also discussed, focusing on scintillators, optical elements, and other luminescent materials.
