Selective Dehydrogenation of Ethanol Using Single Atom Alloy Catalysts

This research aimed to improve the process of non-oxidative catalytic ethanol dehydrogenation to produce acetaldehyde and clean hydrogen gas. Acetaldehyde is an important commodity chemical and is widely used as the starting material for the synthesis of a large number of industrial chemicals such as acetic acid, acetate esters, and pentaerythritol. Hydrogen, the other product of this reaction, is also valuable in many industries including clean energy via hydrogen fuel cells. Although the oxidative dehydrogenation of ethanol also produces acetaldehyde, the byproduct is water. Thus, it is attractive to develop new catalysts that are highly active and selective for the non-oxidative dehydrogenation of ethanol.

Small amounts of platinum, palladium, and nickel were added to the surface of Cu/SiO₂ nanoparticles to enhance the dehydrogenation activity of copper. Pd and Pt atoms are singly dispersed in Cu, forming single atom alloys (SAAs), whereas Ni atoms are highly dispersed in Cu, forming a highly dilute alloy. Our catalytic measurements show that forming PdCu SAAs does not improve the catalytic performance of copper. PtCu SAAs improve the stability of the copper catalyst, but have little effect on the activity. Interestingly, creating highly dilute alloys of Ni in Cu significantly improves both the activity and stability of the copper catalyst. Further study and characterization of the NiCu highly dilute alloy is underway, as this will help us understand the reaction mechanism and identify the active phase, thus guiding the design of new catalysts that further improve the dehydrogenation reactivity.