Localized Phase Transformation Triggering Lattice Matching of Metal Oxide and Carbonate Hydroxide for Efficient CO₂ Photoreduction

Abstract Orderly heterostructured catalysts, which integrate nanomaterials of complementary structures and dimensions into single‐entity structures, have hold great promise for sustainability applications. In this work, it is showcased that air as green reagent can trigger in situ localized phase transformation and transform the metal carbonate hydroxide nanowires into ordered heterostructured catalyst. In single‐crystal nanowire heterostructure, the in situ generated and nanosized Co₃O₄ will be anchored in single‐crystal Co₆(CO₃)₂(OH)₈ nanowires spontaneously, triggered by the lattice matching between the (220) plane of Co₃O₄ and the (001) plane of Co₆(CO₃)₂(OH)₈. The lattice matching allows intimate contact at heterointerface with well‐defined orientation and strong interfacial coupling, and thus significantly expedites the transfer of photogenerated electrons from tiny Co₃O₄ to catalytically active Co₆(CO₃)₂(OH)₈ in single‐crystal nanowire, which elevates the catalytic efficiency of metal carbonate catalyst in the CO₂ reduction reaction (V_CO = 19.46 mmol g⁻¹ h⁻¹ and V_H2 = 11.53 mmol g⁻¹ h⁻¹). The present findings add to the growing body of knowledge on exploiting Earth‐abundant metal‐carbonate catalysts, and demonstrate the utility of localized phase transformation in constructing advanced catalysts for energy and environmental sustainability applications.