Thermodynamics Insights into the Selective Hydrogenation of Alkynes in C2 and C3 Streams

Rationally designed laterally-condensed-catalysts deliver robust activity and selectivity for ethylene production in acetylene hydrogenation

Future carbon management strategies require storage in elemental form, achievable through a sequence of CO2 hydrogenation reactions. Hydrogen is recycled from molecular intermediates by dehydrogenation, and side product acetylene selectively hydrogenated to ethylene. Existing Pd alloy catalysts for gas purification underperform in concentrated feeds, necessitating novel concepts. Atomistic simulations unveil superior selectivity of Pd:C solid solutions that optimize chemisorption energies and preclude sub-surface hydrides, verified here with model thin films. Multiple design criteria deduced from conventional catalysts facilitate synthesizing a self-repairing Pd:C system of a laterally condensed catalyst (LCC). A Pd layer prepared on a designated SiO2 buffer layer enables control of reactive interface, sub-surface volume and extended functional interface towards the buffer. Function and metric are supervised by operando micro-spectroscopy. This catalyst design shows, ethylene productivity >1 kmolC2H4/gPd/hour is reproducibly achieved and benchmarked against known catalysts. Photovoltaics deposition technologies enable scalability on real-world substrates saving active metal. A design-of-experiment approach demonstrates the improvement potential of the LCC approach.