On the Genesis of a Catalyst: A Brief Review with an Experimental Case Study

Abstract

The science of catalysis has a direct impact on the world economy and the energy environment that positively affects the environmental ecosystem of our universe. Any catalyst, before being tested in a reaction, must undergo a specific characterization protocol to simulate its behavior under reaction conditions. In this work, these steps that must be carried out are presented, both generically and with examples, to the support and to the catalyst itself before and after the reaction. The first stage consists of knowing the textural and structural properties of the support used for the preparation of the catalysts. The specific surface area and the pore volume are fundamental properties, measured by N2 adsorption at −196 °C when preparing the catalyst, dispersing the active phase, and allowing the diffusion and reaction of the reactants and products on its surface. If knowing the structure of the catalyst is important to control its behavior against a reaction, being able to analyze the catalyst used under the reaction conditions is essential to have knowledge about what has happened inside the catalytic reactor. The most common characterization techniques in heterogeneous catalysis laboratories are those described in this work. As an application example, the catalytic conversion of CO2 to CH4 has been selected and summarized in this work. In this case, the synthesis and characterization of Cu and Ni catalysts supported on two Al2O3 with different textural properties, 92 and 310 m2/g, that allow for obtaining various metallic dispersions, between 3.3 and 25.5%, is described. The catalytic behavior of these materials is evaluated from the CO2 methanation reaction, as well as their stability from the properties they present before and after the reaction.

Keywords

• catalyst
• catalytic support
• metal oxide
• textural properties
• structural properties
• characterization techniques