CO2 Conversion to Butene via a Tandem Photovoltaic–Electrochemical/Photothermocatalytic Process: A Co-Design Approach to Coupled Microenvironments

We developed a tandem, unassisted, solar-driven
electrochemical and photothermocatalytic process for the
single-pass conversion of CO2 to butene using only simulated
solar irradiation as the energetic input. The two-step process
involves electrochemical CO2 reduction (CO2R) to ethylene
followed by ethylene dimerization to butene. We assessed two
unassisted electrochemical setups to concentrate ethylene in the
CO2R reactor, achieving concentrations up to 5.4 vol% with
1.8% average solar-to-ethylene conversion and 5.6% average
CO2-to-ethylene single-pass conversion under 1-sun illumina-
tion. When the effluent electrochemical gas stream was passed
through the photothermocatalytic ethylene oligomerization
reactor, we generated 600 ppm of butene under 3-sun
illumination. Through analysis of this process, we identified that the presence of H2, CO, and H2O leads to rapid deactivation of the Ni-based ethylene oligomerization catalyst.