Lattice‐Matched S‐Scheme High‐Entropy Oxide Heterojunction for Efficient Visible‐Light‐Driven CO ₂ Photomethanation

Abstract Constructing S‐scheme heterojunctions provides an efficient approach for promoting spatial separation of photogenerated charge carriers, making it highly advantageous for photocatalytic applications. However, the limited interfacial contact between adjacent phases in S‐scheme heterostructures can hinder efficient charge transport, thereby reducing overall photocatalytic performance. To address this issue, an S‐scheme heterojunction (CoCuMgNiZn)O _x @Co ₃ O ₄ with highly connected and matched interfacial lattices is designed in this work. The work function differences, combined with the well‐matched interfacial lattices, promote a modest transfer of photogenerated electrons from the conduction band of Co ₃ O ₄ to the valence band of (CoCuMgNiZn)O _x in the S‐scheme heterojunction, suppressing the recombination of photogenerated carriers. As a result, photo‐generated electrons are more efficiently accumulated in the conduction band of (CoCuMgNiZn)O _x , while the corresponding holes are effectively trapped in the valence band of Co ₃ O ₄ , leading to extended charge carrier lifetimes and enhanced activation of CO ₂ molecules on the catalyst surface. As a result, the (CoCuMgNiZn)O _x @Co ₃ O ₄ exhibited improved visible‐light‐driven CO ₂ photomethanation.