Reductive Transformation of Layered-Double-Hydroxide Nanosheets to Fe-Based Heterostructures for Efficient Visible-Light Photocatalytic Hydrogenation of CO

Conversion of syngas (CO, H-2) to hydrocarbons, commonly known as the Fischer-Tropsch (FT) synthesis, represents a fundamental pillar in today's chemical industry and is typically carried out under technically demanding conditions (1-3 MPa, 300-400 degrees C). Photocatalysis using sunlight offers an alternative and potentially more sustainable approach for the transformation of small molecules (H2O, CO, CO2, N-2, etc.) to high-valuable products, including hydrocarbons. Herein, a novel series of Fe-based heterostructured photocatalysts (Fe-x) is successfully fabricated via H-2 reduction of ZnFeAl-layered double hydroxide (LDH) nanosheets at temperatures (x) in the range 300-650 degrees C. At a reduction temperature of 500 degrees C, the heterostructured photocatalyst formed (Fe-500) consists of Fe-0 and FeOx nanoparticles supported by ZnO and amorphous Al2O3 center dot Fe-500 demonstrates remarkable CO hydrogenation performance with very high initial selectivities toward hydrocarbons (89%) and especially light olefins (42%), and a very low selectivity towards CO2 (11%). The intimate and abundant interfacial contacts between metallic Fe-0 and FeOx in the Fe-500 photocatalyst underpins its outstanding photocatalytic performance. The photocatalytic production of high-value light olefins with suppressed CO2 selectivity from CO hydrogenation is demonstrated here.