Janus Au/CoFe Hetero-Domain Alloy Catalysts for Photo-Driven CO₂ Hydrogenation to Light Olefin

Photothermal catalytic conversion of CO₂ to light olefins is an attractive route for sustainable carbon valorization, yet remains challenged by limited selectivity arising from competing hydrogenation pathways. Here, we develop a ZnO-supported AuCoFe trimetallic catalyst with precisely engineered Janus-type hetero-domain alloy structures, enabling photothermal CO₂ hydrogenation with a CO₂ conversion of 26.2% and a C₂-₄ olefin selectivity of 51.5%, corresponding to an olefin yield of 1.82 mmol g^-1 h^-1. Structural and spectroscopic analyses combined with density functional theory calculations identify a Janus-type Au/CoFe hetero-domain alloy, in which spatially differentiated yet electronically coupled domains enable distinct catalytic functions: Au-rich domains facilitate photothermal CO₂ activation and C₁ intermediate formation via enhanced charge excitation and transfer, while CoFe-rich domains favor C─C coupling and chain growth. This work provides a practical strategy for improving selectivity for photothermal catalysts that couple compositional heterogeneity with electronic structure modulation, enabling efficient and selective CO₂ conversion to higher-value olefins.