Dual-Temperature Photothermal Tandem Catalysis for CO2 Conversion to Olefins

Abstract

We report a dual-temperature photothermal tandem system that overcomes this temperature mismatch and enables efficient CO2 hydrogenation to light olefins in a single reactor. A graphene-modified In2O3 top bed drives the RWGS reaction and provides strong broadband absorption for efficient photothermal heating, thereby achieving higher temperatures for CO generation. The CO then feeds into a downstream K-doped Fe2O3 bed maintained at a lower temperature suitable for FTS to produce light olefins. This vertically arranged, dual-temperature configuration spatially separates and couples RWGS and FTS, effectively synchronising the tandem pathway. As a result, the system achieves a light-olefin production rate of 52.1 μmol g⁻¹ h⁻¹ with 69% selectivity at 0.05 MPa under photothermal conditions without external heating.