New catalyst cuts energy needed to turn captured CO2 into ethylene by half
Researchers have doubled the efficiency of converting captured carbon dioxide into ethylene, a major industrial chemical, using a new dilute alloy catalyst. The breakthrough could make carbon capture economically viable by dramatically reducing the energy penalty of converting trapped CO2 into valuable products rather than simply storing it.
Originaltitel: Dilute alloy electrocatalysts enable asymmetric C–C coupling for ethylene production from a CO2 post-capture liquid
<p>Direct air capture of CO2 often uses alkali hydroxides to form carbonate; however, releasing CO2 and regenerating alkali hydroxides requires an energy-intensive thermal cycle at ~900 °C. Reactive capture systems instead seek to integrate CO2 release with its chemical reduction in the pathway to fuels and chemicals. Here we focus on a purely electrosynthetic route, beginning by examining why previous attempts at electrified ethylene synthesis from carbonate post-capture liquids have suffered from low overall energy efficiencies. We find that a hydrophilic environment and limited rate of CO2 generation in situ lead to low CO2 availability and consequently low *CO coverage on the catalyst surface, and that this hinders C–C coupling. We identify dilute alloy catalysts that implement asymmetric CO–CHO coupling, a lower-barrier route to C–C coupling compared with the conventional symmetric pathway. We report a 51% ± 2% ethylene Faradaic efficiency, a 66 wt% ± 2% concentrated ethylene stream and a 20% end-to-end energy efficiency at 200 mA cm−2. The energy efficiency is a twofold improvement over the most efficient prior report of ethylene production via electrified reactive capture.</p>