Metal-Support Interaction in Oxide-Supported Fine Metal Particles

对<Nb_2> <O_5> -负载Rh和<Nb_2> <O_5> -促进Rh催化剂进行了<H_2>和CO的化学吸附、TPD、FTIR以及CO加氢、乙烷氢解、环己烷脱氢和氢解等多种催化反应的表征。Rh/ <Nb_2> <O_5>和Rh/ <TiO_2>在强金属-支撑相互作用（SMSI）的性质上存在一定的差异：(1)Rh/ <Nb_2> <O_5>中的SMSI部分是由低温还原（LTR）和723 K真空抽真空引起的；(2) Rh- <Nb_2> <O_5>相互作用对氢解活性的抑制作用明显大于Rh- <TiO_2>相互作用；等等......。<Nb_2> <O_5> -促进的<Nb_2> <O_5>催化剂沉积在Rh/ <SiO_2>催化剂上，也表现出SMSI行为，其相互作用与Rh/ <Nb_2> <O_5>催化剂一样强。根据这些结果讨论了一种可能的SMSI模型。

The <Nb_2> <O_5> -supported Rh and <Nb_2> <O_5> -promoted Rh catalysts have been characterized by <H_2> and CO chemisorption, TPD, FTIR, and various catalytic reactions such as CO hydrogenation, ethane hydrogenolysis, and cyclohexane dehydrogenation and hydrogenolysis. There appeared to be some differences in the nature of strong metal-support interaction (SMSI) between Rh/ <Nb_2> <O_5> and Rh/ <TiO_2> : (1) SMSI in Rh/ <Nb_2> <O_5> is partly induced even by a low-temperature reduction (LTR) followed by evacuation in vacuo at 723 K; (2) there was much more drastic suppression in the hydrogenolysis activity by the Rh- <Nb_2> <O_5> interaction than the Rh- <TiO_2> interaction; and so on. The <Nb_2> <O_5> -promoted Rh catalyst, containing <Nb_2> <O_5> deposited onto a Rh/ <SiO_2> catalyst, also exhibit the SMSI behavior, in which the interaction was as strong as that in Rh/ <Nb_2> <O_5> . A possible model for SMSI was discussed in the light of these results.