A Photothermocatalytic Reactor and Selective Solar Absorber for Sustainable Fuel Synthesis by Ethylene Oligomerization

Utilizing solar thermal energy for thermochemical processes enables sustainable generation of fuels and chemicals. Here, we present a scalable photothermocatalytic reactor with a selective solar absorber that converts sunlight into thermal energy for fuel synthesis. The fabricated absorber achieves a calculated maximum temperature of 249 °C under one sun illumination and 130 °C under ambient operating conditions (25 °C, 1 atm). The application of the photothermocatalytic reactor was demonstrated using an industrially relevant ethylene oligomerization reaction. A homogeneous reaction was performed in a batch mode and yielded a distribution of liquid hydrocarbon chains with 6 to 24 carbon atoms. A heterogeneous reaction was performed in a flowthrough configuration, yielding butene and hexene products. Finally, simulated results for a larger-scale reactor predict spatially uniform maximum temperatures up to 120 °C and 210 °C under one and three sun illumination, demonstrating the potential to generate fuels at bigger scales.