Abstract: The development of novel technologies for oxidative dehydrogenation of cheap and widely available light C2-C3 alkanes is great challenge in terms of cooperation between industry and scientific community. The one of most effective catalysts for C2-C3 hydrocarbons transformation are Mo-V-Nb-Te oxide compositions [1,2]. It was established that the modification of MoVNbTeO mixed oxide by Bi resulted in the improvement of its catalytic properties in oxidative dehydrogenation of ethane (ODE). The investigation of Bi-modified MoVNbTeO catalysts was carried out with the purpose to establish the influence of introduced Bi on the surface dynamics and structural features of MoVNbTeO catalysts under reducing ODE conditions (C2H6/O2 > 1). The application of NAP-XPS and in situ XRD methods provided the reliable experimental data about surface and bulk transformations, respectively. NAP-XPS study showed that Bi-modified catalysts were characterized by enhanced surface/subsurface Te concentration under reducing ODE conditions while compared with unmodified catalyst. EXAFS spectroscopy revealed that the local environment of Bi within MoVNbTeO particles corresponded to positions within extended six-membered channels of the M1 structure, which are similar to Te sites. The increase in the temperature of M1 phase destruction in ethane flow for Bi-modified catalysts was revealed using in situ XRD. The crystal lattice of the modified M1 phase did not undergo compression along the c-axis during heating in C2H6/He flow, in contrast to the unmodified catalyst, indicating the influence of Bi on Te mobility within the extended channels of the M1 structure. Incorporation of Bi caused the limitation of Te mobility within channels, preventing its reduction and removal resulting in a significant decrease in the degree of deactivation for Bi-modified ODE catalysts at high temperature under reducing ODE conditions

Cite: Svintsitskiy D.A. , Kardash T.Y. , Lazareva E.V. , Saraev A.A. , Fedorova E.A. , Vorokhta M. , Smid B. , Bondareva V.M.
Bi-Modified MoVNbTeO Catalysts for Oxidative Dehydrogenation of Ethane: NAP-XPS and In Situ XRD Study
XI International Conference Mechanisms of Catalytic Reactions 07-11 Oct 2019