【作者】 徐明； 李长明； 高娃； 陈浩； 卫敏；

【Author】 Ming Xu;Changming Li;Wa Gao;Hao Chen;Min Wei;Beijing University of Chemical Technology;

【机构】 北京化工大学化工资源有效利用国家重点实验室；

【摘要】 二维层状材料独特的物理化学性质为功能材料研究带来了新机遇和挑战,在诸多领域表现出巨大的优势和潜在的应用前景。水滑石(LDHs)是一类无机层状二维纳米材料,其主体层板金属元素的可调变性及其结构拓扑转变行为,为制备负载型金属纳米催化剂提供了新途径。我们创制了"层状前体拓扑转变方法":将催化活性金属元素引入LDHs层板,经原位还原处理,获得了一系列负载型镍基单金属、金属间化合物、双金属合金、双金属异质结催化剂样品,在选择性加氢、水煤气变换反应中显示了优异的催化性能。通过精确控制结构拓扑转变的过程,实现了活性位结构在介观、微观尺度上的调控,研究了表面缺陷结构、几何/电子效应、金属-载体相互作用(酸碱协同催化、界面协同催化)对催化活性和选择性的影响1,2。采用一系列原位研究手段(红外、拉曼、透射电镜、X射线光电子能谱、X射线吸收谱),深入研究了水煤气变换反应的本征活性位,确认了反应机理3,4。更多还原

【Abstract】 Layered double hydroxides(LDHs) are a class of 2D functional materials with promising applications. The unique structural topotactic transformation of LDHs provides a facile route for the preparation of supported metal nanocatalysts. By virtue of this strategy, we developed several supported Ni-based mono-metal, intermetallic compounds and bi-metal alloy nanocatalysts, which showed excellent catalytic preformance toward selective hydrogenation reactions or water-gas shift reaction(WGSR). Through a fine control over topotactic transformation process of LDHs precursors, the microstructure of active center was precisely tuned. The influences of surface defects, geometrical/electronic effect, metal-support interactions on catalytic behavior were investigated in detail. In addition, a combination study including in situ and operando EXAFS, in situ XPS, in situ TEM, in situ DRIFTS measurements was used to substantiate a new redox mechanism of WGSR based on interfacial synergistic catalysis. This preparation approach was also demonstrated in the synthesis of other metal nanocatalysts(e.g., Cu, Fe, Co).更多还原