Kinetic Study of the Hydrogenation of Unsaturated Aldehydes Promoted by CuPtx/SBA-15 Single-Atom Alloy (SAA) Catalysts

A comprehensive study of the kinetics of the catalytic hydrogenation of unsaturated aldehydes, in particular of cinnamaldehyde, promoted by CuPtx/SBA-15 single-atom alloy catalysts was carried out in order to identify trends as a function of the composition of the bimetallic nanoparticles, that is, of the value of x. The optimum performance reported by us recently [ ACS Catal. 2019, 9, 9150−9157] in terms of selectivity toward the formation of cinnamyl alcohol, the desired product, by the catalyst with x = 0.005 was corroborated. A rapid decrease was seen in catalytic activity in batch reactors with all catalysts, in particular with pure Cu/SBA-15. This was ascribed, based on DFT calculations and microkinetic simulations, to the relative weak adsorption of the reactant compared to that of the products, which leads to the blocking of catalytic sites by the latter early on in the catalytic runs. It was determined that selectivity is controlled by the relative values of the initial rate constants for hydroge...