Synthesis and characterization of cobalt-doped molybdenum carbides produced in a fixed bed reactor

Abstract

The demand for cheaper production processes of materials has been the focus of several studies in the last years, mainly by the industries, in order to relate the cost-benefit associated with the low risks to the environment, and the ease of transportation and use. The transition metal carbides are gaining emphasis due to their catalytic activity, stability and selectivity in a wide range of reactions. The purpose of doping the molybdenum carbide with cobalt is the seek for a change in the structure of the carbide so that an improvement of its catalytic activity occurs. The aim of this work is to study the synthesis and characterization of semiconductor materials with the carbide type structure, produced with nationally and locally abundant elements, specifically at Rio Grande do Norte state, using the gas-solid reaction method in a fixed-bed reactor. Based on a bibliographical survey, and in previously obtained results, the compositions of the materials to be studied will be Mo2C doped with cobalt (5% and 10%). The physico-chemical characteristics of the material were evaluated using several analytical techniques, such as X-ray diffraction (XRD), thermogravimetric analysis (TGA), surface area by the BET method, granulometry and scanning electron microscopy (SEM). With its characterization, it is possible to understand the relation between its structural properties and its activity as heterogeneous catalysts. The results of the thermal analysis by TGA of the precursor powder were carried out in order to identify the mass losses of the material and to verify the operating temperatures of the fixed bed reactor for the production of the carbide. From the XRD results, it was verified the formation of cobalt-doped molybdenum carbide synthesized by the wet method, and the phases and characteristic peaks of each material were identified.