Catalyst parameters determining activity and selectivity of supported gold nanoparticles for the aerobic oxidation of alcohols:: The molecular reaction mechanism
Catalyst parameters determining activity and selectivity of supported gold nanoparticles for the aerobic oxidation of alcohols:: The molecular reaction mechanism
复制标题
DOI：
10.1002/chem.200701263
复制
发表时间：
2008-01-01
影响因子：
4.3
通讯作者：
Garcia, Hermenegildo
中科院分区：
文献类型：
--
作者：
Abad, Alberto;Corma, Avelino;Garcia, Hermenegildo
如前所述，对于无溶剂反应，氧化铈负载的金纳米颗粒也是有机溶剂中醇类有氧氧化的优良非均相催化剂。在有机溶剂中，甲苯是一种方便的溶剂。系统研究了粒径和含金量对载体的影响，发现活性与外部金原子总数和载体的表面覆盖率呈线性相关。在不同载体但金粒度和含量相近的催化剂中，金在二氧化铈上的活性最高。通过动力学研究（sigma（+）参数、动力学同位素效应、温度、醇浓度和氧压的影响），提出了由金属-醇酯的形成、β -氢化物从碳向金属的转变和M-H氧化组成的机理建议，解释了所有实验结果。
As previously reported for for solventless reactions, gold nanoparticles supported on ceria are also excellent general heterogeneous catalysts for the aerobic oxidations of alcohols in organic solvents. Among organic solvents it was found that toluene is a convenient one. A systematic study on the influence of the particle size and gold content on the support has established that the activity correlates linearly with the total number of external gold atoms, and with the surface coverage of the support. Amongst catalysts with different supports, but similar gold particle size and content, gold on ceria exhibits the highest activity. By means of a kinetic study (influence of sigma(+) parameter, kinetic isotopic effect, temperature, alcohol concentration and oxygen pressure) a mechanistic proposal consisting of the formation of metal-alcoholate, beta-hydride shift from carbon to metal and M-H oxidation has been proposed that explains all experimental results.