摘要
光催化氧还原制备过氧化氢具有节能、环保等优点.然而,低活性以及低选择性的问题限制了其实际应用.基于金属离子耦合电子转移机制,本文通过浸渍-煅烧法合成了原子分散的钪路易斯酸位点修饰的氮化碳,光合成过氧化氢速率高达55μmol h^(-1),是氮化碳的6.2倍.光催化性能的提升归因于原子分散钪路易斯酸位点与·O_(2)^(-)结合,提高了O_(2)的得电子能力,减少了·O_(2)^(-)逆反应的发生,促进了氧还原反应进行.密度泛函理论模拟及Koutecky-Levich分析表明,钪原子的引入减少了O–O键的断裂,提高了合成过氧化氢的选择性.本研究提出了一种路易斯酸单金属位点光催化剂设计新概念,可同时提升催化反应活性及选择性.
Photocatalytic reduction of oxygen represents a promising way to produce hydrogen peroxide(H_(2)O_(2))owing to the merits of energy saving and environmental benignancy.However,the low activity and selectivity of the photocatalyst impede its practical application.Herein,following the principle of metal ion-coupled electron transfer,we have fabricated a class of graphitic carbon nitride(g-C_(3)N_(4))decorated with atomically dispersed scandium Lewis acid(Sc/H-CN)using a facile impregnation-calcination method.The as-synthesized Sc/H-CN exhibits excellent H_(2)O_(2)production performance with a rate of 55μmol h^(-1),which is 6.2 times over bare CN.The improved performance is ascribed to the enhancement of O_(2)electron-accepting capability through binding of Sc Lewis acid sites with intermediate·O_(2)^(-),inhibiting its reverse reaction.Moreover,density function theory(DFT)calculation and Koutecky-Levich analysis show that the reduced O-O bond breakage is responsible for the high selectivity in the production of H_(2)O_(2).This work provides a new strategy for the design of photocatalysts equipped with appropriate active sites towards various applications.
作者
姚爽
唐婷
申勇立
杨帆
安长华
Shuang Yao;Ting Tang;Yongli Shen;Fan Yang;Changhua An(Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion,School of Chemistry and Chemical Engineering,Tianjin University of Technology,Tianjin 300384,China;Tianjin Key Laboratory of Advanced Functional Porous Materials,Institute for New Energy Materials&Low-Carbon Technologies,School of Materials Science and Engineering,Tianjin University of Technology,Tianjin 300384,China)
基金
supported by the National Natural Science Foundation of China(21771137 and 21971190)
the Natural Science Foundation of Tianjin(20JCQNJC00520)。
