Developing Oxygen Vacancy Rich Perovskite for Broad‐Spectrum‐Responsive Photothermal Assisted Photocatalytic Dehydrogenation of MgH ₂

Abstract Magnesium hydride (MgH 2 ) has been featured as a promising hydrogen storage medium however faces deployment barriers due to high thermodynamic stability and sluggish dehydrogenation kinetics. To address these limitations, a broad‐spectrum‐responsive SrTiO 3 ‐based perovskite (STO‐450) particle, engineered with oxygen vacancies is introduced, as an effective photothermal‐assisted photocatalyst for enhancing MgH 2 dehydrogenation. It optimized MgH 2 ‐30 wt.% STO‐450 composite desorbs 4.41 wt.% H 2 at 184.7 °C under 1.152 W cm −2 (12 sun) irradiation, and 2.00 wt.% H 2 at 152.2 °C under 0.576 W cm −2 (6 sun). In situ XPS, fs‐TAS, and DFT reveal that oxygen vacancies act as electron traps, extending carrier lifetime and facilitating directional charge transfer across the MgH 2 /STO‐450 heterointerface. This interfacial charge modulation substantially accelerates dehydrogenation kinetics. A levelized cost of hydrogen analysis shows over 50% energy cost reduction compared to conventional thermal routes. This work enables a practical strategy to significantly reduce the energy cost associated with long‐distance H 2 transport and high‐pressure storage infrastructures.