Theoretical study of the CO catalytic oxidation on Au/SAPO-11 zeolite

Quantum chemistry calculations were carried out, using ONIOM2 methodology, to investigate the CO adsorption and oxidation on gold supported on Silicoaluminophospates (SAPO) molecular sieves Au/SAPO-11 catalysts. Two models were studied, one containing one Au atom per site (AuASAPO-11), and the other with two Au atoms per site (Au₂ASAPO-11). The results reveal that the CO adsorption and oxidation are exothermic on Au/SAPO11 with an ΔE of -41.0 kcal/mol and DE = -52.0 kcal/mol, for the adsorption and oxidation, respectively. On the Au₂-SAPO-11 model, the CO adsorption and oxidation reaction occur, with a ΔE of -29.7 kcal/mol and -52 kcal/mol, respectively. According to our results, the oxidation reaction exhibits an Eley-Rideal type mechanism with adsorbed CO. The theoretical calculations reveal that this type of material could be interesting to disperse Au and consequently to strengthen its catalytic use for different reactions.