Feature of catalysis on bimetallic alloys Zr with V, Mo, and Fe in the reaction of methanol oxidation

Arif Efendi,Lyudmila Koja-Rova,Elmir Babayev,Adila Aliyeva,Lala Magerramova

doi:10.3906/kim-2010-9

Abstract

Catalytic behaviors of bimetallic catalysts-alloys of zirconium with vanadium, molybdenum, and iron was investigated in the oxidative dehydrogenation of methanol. The conditions for the formation of the catalyst’s active surface were revealed. The conversion of methanol into formaldehyde, dimethyl ether, and dimethoxymethane on bimetallic catalysts was studied. The characterization of catalysts was performed by XRD, XPS, and SEM. It was shown that the activity of samples increases after О2 + Н2 treatment and was associated with segregation of the active components of alloys (V, Mo) on the surface of catalysts and realization of their optimal oxidation state under catalysis conditions.

Highlights

Bimetallic catalysts and their industrial application on worldwide scale in petroleum reforming processes have played an important role in production of valuable hydrocarbons [1,2]
It is proved that bimetallic catalysts based on ZrMo2: Ar (Zr) alloys with V, Mo, Fe show rather high activity and selectivity in the reaction of methanol oxidation to FA, Dimethyl ether (DME), and DMM after О2 + Н2-treatment
This happens due to the segregation of Scheme: According to the catalytic results, a reaction Scheme can be proposed the active components of alloys (V, Mo) on the surface of the catalysts in an intermediate oxidation state and, further, to the realization of their optimal oxidation state under catalysis conditions

Summary

Introduction

Bimetallic catalysts and their industrial application on worldwide scale in petroleum reforming processes have played an important role in production of valuable hydrocarbons (lead-free gasoline, safe for environment) [1,2]. Further studies showed [17,18,19,20,21,22,23] that following factors had a great impact on the catalytic behavior of vanadiumsupported catalysts: (i) the nature of V n+─ O species, i.e., coordination, aggregation, and oxidation state of V-species; (ii) redox properties of the catalysts, i.e., the V5+/V4+ ratio in reaction, (iii) acid–base character of the catalysts (as well as the support), that determines the selectivity of reaction products. The reducibility and structure of surface vanadium oxide particles and the acidbase character of catalysts, in addition to their catalytic properties in the oxidative dehydrogenation of alkanes, strongly depend on the metal oxide used as a support and the vanadium content of the V5+ tetrahedral species [19]. All considered vanadium and molybdenum catalysts belong to supported oxides, with different methods of preparation The correlation of their activity with the type of support, acidity, structure, number of redox centers was examined. Alloys can be considered the models, on which conditions, affecting for the formation of the active surface can be studied [32,33]

Experimental

Results and discussion

Conclusion