已有实验表明贵金属Pt能够随外界氧化还原条件的改变,自发地在钙钛矿Ca Ti O3内部和表面之间迁移,有效抑制贵金属颗粒的烧结,使得贵金属长期保持高效的催化活性,因此该体系被称为汽车尾气"智能催化剂"。但当前对该体系中贵金...已有实验表明贵金属Pt能够随外界氧化还原条件的改变,自发地在钙钛矿Ca Ti O3内部和表面之间迁移,有效抑制贵金属颗粒的烧结,使得贵金属长期保持高效的催化活性,因此该体系被称为汽车尾气"智能催化剂"。但当前对该体系中贵金属与载体之间的相互作用,以及贵金属迁移特性发生的条件以及程度的研究很少。采用第一性原理计算方法与集团展开法以及蒙特卡洛方法相结合构建Pt Ox-Ca O-Ti Ox三元相图,对可再生汽车尾气催化剂Pt掺杂Ca Ti O3体系进行了理论研究。第一性原理相图分析表明,Pt能够以不同浓度取代Ca Ti O3中的Ti原子;而热力学相图分析表明,Pt掺杂到Ca Ti O3中将形成固溶体,更重要的是Pt能够在氧化还原条件下与Ca Ti O3形成固溶体或者析出,与"智能催化剂"的概念相一致。此外,相图分析还预测了其它一些氧化物以及合金结构的存在,并得到了这些物质之间的相变规律。这些结果将为实验工作提供有益的帮助,有利于开发高效的汽车尾气催化剂。展开更多
Electrochemical N_(2) reduction provides a green and sustainable alternative to the Haber-Bosch technology for NH_(3 )synthesis.However,the extreme inertness of N_(2) molecules is a formidable challenge,which requires...Electrochemical N_(2) reduction provides a green and sustainable alternative to the Haber-Bosch technology for NH_(3 )synthesis.However,the extreme inertness of N_(2) molecules is a formidable challenge,which requires the development of an active electrocatalyst to drive the N_(2) reduction reaction(NRR)for NH_(3) production at ambient conditions.Herein,we demonstrate the development of La-doped TiO_(2) nanorods as an efficient NRR electrocatalyst for ambient NH3 synthesis.The optimized La-TiO_(2) catalyst offers a large NH_(3) yield of 23.06 pg h1 mgcat 1 and a high Faradaic efficiency of 14.54%at-0.70 V versus reversible hydrogen electrode in 0.1 M L1CIO_(4),outperforming most La-and Ti-based catalysts reported before.Significantly,it also demonstrates high electrochemical stability and its activity decay is negligible after 48 h test.The mechanism is further revealed by density functional theory calculations.展开更多
文摘已有实验表明贵金属Pt能够随外界氧化还原条件的改变,自发地在钙钛矿Ca Ti O3内部和表面之间迁移,有效抑制贵金属颗粒的烧结,使得贵金属长期保持高效的催化活性,因此该体系被称为汽车尾气"智能催化剂"。但当前对该体系中贵金属与载体之间的相互作用,以及贵金属迁移特性发生的条件以及程度的研究很少。采用第一性原理计算方法与集团展开法以及蒙特卡洛方法相结合构建Pt Ox-Ca O-Ti Ox三元相图,对可再生汽车尾气催化剂Pt掺杂Ca Ti O3体系进行了理论研究。第一性原理相图分析表明,Pt能够以不同浓度取代Ca Ti O3中的Ti原子;而热力学相图分析表明,Pt掺杂到Ca Ti O3中将形成固溶体,更重要的是Pt能够在氧化还原条件下与Ca Ti O3形成固溶体或者析出,与"智能催化剂"的概念相一致。此外,相图分析还预测了其它一些氧化物以及合金结构的存在,并得到了这些物质之间的相变规律。这些结果将为实验工作提供有益的帮助,有利于开发高效的汽车尾气催化剂。
文摘Electrochemical N_(2) reduction provides a green and sustainable alternative to the Haber-Bosch technology for NH_(3 )synthesis.However,the extreme inertness of N_(2) molecules is a formidable challenge,which requires the development of an active electrocatalyst to drive the N_(2) reduction reaction(NRR)for NH_(3) production at ambient conditions.Herein,we demonstrate the development of La-doped TiO_(2) nanorods as an efficient NRR electrocatalyst for ambient NH3 synthesis.The optimized La-TiO_(2) catalyst offers a large NH_(3) yield of 23.06 pg h1 mgcat 1 and a high Faradaic efficiency of 14.54%at-0.70 V versus reversible hydrogen electrode in 0.1 M L1CIO_(4),outperforming most La-and Ti-based catalysts reported before.Significantly,it also demonstrates high electrochemical stability and its activity decay is negligible after 48 h test.The mechanism is further revealed by density functional theory calculations.
基金supported by the major program funds of State Grid Shaanxi Electric Power Company Limited (5226KY23000P)the Startup funds of Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China (U03210019)。
