Highly Selective Conversion of H2S/CO2 and Reaction Mechanism with CeO2 Loading of MgO as Catalysts

The possibility and limits of the reaction between H2S and CO2 are analyzed from a thermodynamic perspective. The thermodynamic balance of the reaction is severely constrained by temperature, which is conducive for the reaction conversion and generates CO and S2 products at high temperatures. Using the alkaline oxide MgO as the body catalyst, different metal salts and metal oxides are doped or loaded to adjust the acidity or alkalinity strength of their surfaces, and the generation selectivity for different reaction products is facilitated. The results show that an increase in the alkalinity is more conducive for the competitive reaction of COS generation, and catalysts with medium alkaline strength favors the reaction in the direction of generating CO and S2, whereas the conversion rate of the reaction decreases under weak alkalinity and acidity. The adsorption of H2S and CO2 gas molecules on the MgO-based catalyst and the reaction mechanism of binding to COS or CO are further analyzed through DFT calculations. The intermediate product molecules are easily desorbed after weakening the alkaline strength, which tends to produce CO and S2, and the reaction reaches equilibrium quickly. High-temperature synchronous catalysis can effectively convert H2S and CO2 into usable resources.