Lanthanum-Mediated Bulk-Surface Synergistic Engineering of Ferroelectric BaTiO3 for Photothermal CO2 Hydrogenation to Ethylene with High Selectivity

Abstract Ferroelectric semiconductors hold considerable promise for photothermal catalytic CO2 hydrogenation to high-value hydrocarbons, owing to their intrinsic polarization electric field that facilitates charge separation. However, their practical performance is severely limited by weak bulk polarization, rapid carrier recombination at high temperatures, insufficient surface active sites, and poor C–C coupling efficiency. Herein, we report a lanthanum (La)-mediated bulk–surface synergistic strategy to engineer ferroelectric BaTiO3 (BTO) for highly selective photothermal CO2 hydrogenation to C2H4. A series of La2O3@BaTi1–xLaxO3–δ (x%-BTLO) composites were fabricated via a one-pot hydrothermal method. La doping induces lattice expansion along the [001] polar axis, which significantly strengthens the bulk polarization electric field, raises the Curie temperature above 200 °C, and promotes charge delocalization through orbital hybridization, thereby suppressing bulk carrier recombination under photothermal conditions. Meanwhile, the surface-decorated La2O3 nanoparticles form a tight heterojunction with the La-doped BaTi1–xLaxO3–δ substrate, which accelerates interfacial charge transfer and provides active sites for boosting C–C coupling. Consequently, the optimized 10%-BTLO catalyst exhibits a C2H4 yield of 5.88 mmol·g–1·h–1 with a selectivity of 79.7% at 200 °C and shows long-term stability over 120 h. This work establishes a feasible bulk–surface synergistic design principle for ferroelectric catalysts and offers a pathway to achieve efficient and selective photothermal conversion of CO2 into high-value C2 + products.