Strain-Driven In Situ Ni Exsolution on (Sr,Ca)(Ti,Ni)O₃ (100) Facets Boosts Hydrogen Spillover and Selective CO₂-to-C₂₊ Photoreduction

Photocatalytic CO₂ reduction offers a sustainable route to value-added chemicals, yet conventional systems suffer from limited efficiency and hydrocarbon selectivity due to the spatial mismatch between CO₂ adsorption and proton sources, delaying proton-coupled electron transfer (PCET). Here, we construct a Ni/(Sr,Ca)(Ti,Ni)O₃ heterostructure (Ni/SCTNO) via molten salt exsolution and aluminothermic reduction. Ca²⁺ doping introduces lattice strain, which drives the in situ exsolution of Ni nanoparticles on the (100) facet, while oxygen vacancies create a positive space charge layer. These effects synergistically form Schottky junctions that act as hydrogen spillover centers, enabling directional H* migration to CO₂ sites and spatiotemporally coordinating proton–electron transport. Under simulated sunlight, CH₄, C₂H₄, and C₂H₆ yields reach 41.89, 18.01, and 16.53 µmol·g⁻¹·h⁻¹, respectively, with a total hydrocarbon selectivity of 55.03%, surpassing most reported perovskite-based photocatalysts. This work presents an integrated strategy combining heterointerface engineering, strain regulation, and surface modification for efficient CO₂-to-multicarbon fuel conversion.