Insights into the Light‐Promoted Synergy Among Active Oxygen, Oxygen Vacancies, and H ₂ O Adsorption Sites in Ni/La ³⁺ ‐Doped CeO ₂ for Highly Efficient Photothermocatalytic Cellulose Steam Reforming to Syngas

Abstract Photothermocatalytic cellulose steam reforming has emerged as a sustainable strategy in balancing energy conservation and efficiency; the paramount stumbling block in its industrial application is the excessive byproducts and rapid deactivation due to vigorous reaction. This study substantiates how doping La 3+ in ceria loaded with nickel nanoparticles maximizes the role of interfacial sites as the intrinsic active centers, overcoming this production sensitivity. The optimized H 2 and CO production rates (4845.9 and 2778.5 mmol g −1 catalyst h −1 ) are achieved by modulating the molar ratio of Ce to La as 3:1 (Ni/Ce 3 La 1 catalyst). Comprehensive characterizations provide insight into a unique synergy between Ni nanoparticles and La 3+ ‐doped CeO 2 with active lattice oxygen activation and enhanced water adsorption capacity by increasing oxygen vacancies due to La 3+ doping, which are responsible for tar conversion to H 2 ‐rich syngas by two distinct pathways. Additionally, significant photoactivation is found to accelerate the oxygen migration from both ceria lattice and water adsorbed on oxygen vacancies, particularly promoting the oxidation of byproducts to syngas. The findings pose a promising approach for achieving antideactivation with high light‐to‐fuel efficiency in photothermocatalytic cellulose steam reforming.