Studies on the catalytic properties of metal oxide thin film on the molten salt liquid film

在某些情况下，最初负载在基底上的催化剂变得熔融，与基底相互作用，并最终在化学反应过程中表现出其自身的特性。从催化剂设计的角度来看，阐明液膜-基底相互作用的机理是很重要的，催化剂和/或基底的表面实际上确实表现出它们的特定特性。本工作的目的是阐明化学反应过程中液膜与基底之间的相互作用机理。在这方面，金属氧化物薄膜已被用作衬底表面的模型。采用刘易斯酸性熔盐ZnBr_2-NaBr（623 K）作为成膜材料，采用射频反应溅射法，通过电解氧化沉积的金属薄膜，在玻璃衬底上制备金属氧化物薄膜。通过流动电位法测定所获得的金属氧化物膜的带电状态。在不同溶液酸度条件下进行了测量，并根据锌-锌浓差电池电动势的测量结果，研究了ZnBr_2-NaBr熔体在623 K时的酸碱性质。ZnBr_2 + Br^- = ZnBr_3^- K_1ZnBr_3^- + Br ^-= ZnBr_4^<2->K_2在623 K时，平衡常数K_1和K_2分别为5.0 × 10 ~（^2）和1.0 × 10 ~（^2）。ZnBr^-_NaBr熔体的酸性比溴铝酸盐熔体的酸性弱。

In some cases, the catalyst which is originally supported on the substrate becomes melting, interacts with the substrate and finally exhibit its own characteristics during the course of a chemical reaction. It is important to clarify the mechanism of the liquid film - substrate interaction from the view point of catalyst design.The surface of the catalyst and/or substrate actually does exhibit the specific characteristics of them. The purpose of this work is to clarify the interaction mechanism between the liquid film and the substrate during chemical reaction. In this respect, the metal oxide thin film has been used as a model of the substrate surface. Lewis acidic molten salt, the ZnBr_2-NaBr melts at 623K, whose acidity can be controlled by the composition and the component have been used as a material for the liquid film.Metal oxide film was prepared on the glass substrate by a reaction RF sputtering method of by an electrolytic oxidation of deposited metal thin film. The charged state of the metal oxide film obtained was determined by an streaming potential method. The measurements were performed at various solution acidity conditions.The acid-base properties of the ZnBr_2-NaBr melts at 623K were investigated on the basis of the electromotive force measurements of a zinc-zinc concentration cell. The following two chemical equilibria were postulated to describe the acid-base character of the melts:ZnBr_2 + Br^- = ZnBr_3^- K_1ZnBr_3^- + Br^- = ZnBr_4^<2-> K_2The equilibrium constants K_1 and K_2 are determined to be 5.0x10^2 and 1.0x10^2, respectively, at 623K. The acidity of ZnBr^-_NaBr melts is essentially weaker than that of bromoaluminate melts.