Ti ³⁺ ‐Driven Modulation of Ni Encapsulation via TiO ₂ Support Engineering Enables High‐Performance H ₂ ‐Production from Low‐Carbon Alcohols Reforming

Abstract Strong metal‐support interaction (SMSI) plays a pivotal role in heterogeneous catalysis, yet precise control over SMSI states under harsh reducing conditions remains challenging. Herein, a defect engineering strategy is proposed to modulate SMSI by tailoring the reducibility of anatase TiO 2 through high‐temperature annealing. By systematically varying the defect density of TiO 2 (confirmed by EPR, XPS and XAFS), a quantitative correlation is established between Ti 3+ defect density, Ti─O bond stability, and Ni encapsulation degree. Defect‐rich TiO 2 suppresses excessive Ti 3+ migration via stabilizing Ti─O bond, achieving a precisely 51% Ni encapsulation by ultrathin TiO 2 overlayers (0–1.6 nm, HAADF‐STEM). This optimized structure exhibits exceptional stability (>100 h at 350 °C) and high hydrogen yield (722.1 mmol g cat −1 h −1 ) in methanol steam reforming, outperforming state‐of‐the‐art Ni‐based catalysts. Mechanistic studies reveal that defect‐mediated H‐spillover resistance (H 2 ‐TPR/XPS) and reduced energy barriers for methanol dehydrogenation (DFT) enhance both activity and durability. Furthermore, the universality of this strategy is validated in ethanol and propanol reforming, demonstrating strong structural stability under high‐temperature reduction (500 °C for 240 h) conditions. This work not only deciphers the thermodynamic origin of SMSI governed by defect chemistry but also provides a general paradigm for designing encapsulation‐controlled catalysts in energy‐intensive reactions.