Spin‐Orbit Coupling Amplifying Polarization State for Regulating Bulk Charge Vectorial Transfer Dynamics at Spatiotemporal Scale for Towering H ₂ Generation

Deblocking the constraints for charge transfer dynamics spanning the spatiotemporal scale from femtosecond to second along with spatial scale from atom to micrometer displays a significant challenge in liberating photocatalysis efficiency. Herein, the challenge is well addressed by d-p spin-orbit coupling from spin-state FeS₂ to amplify CdS polarization for exceptional H₂ photocatalytic generation. The spin-polarized states amplified by the upshift energy levels of Fe 3d and Cd 3d vectorially boost charge carrier transfer dynamics at spatial redox active sites with extending nanosecond lifetime up to 2.48 times; remarkably, energy barrier for chemical adsorption and activation of ^*H and ^*OH at S 2p from FeS₂ and Cd 3d of CdS are decreased by their electron transfer into the corresponding unoccupied orbits, respectively, performing Volmer-Heyrovsky and Volmer-Tafel paths for H₂ generation with activation energy down to 70.77%. As a result, the amplified spin-polarized catalyst presents an exceptional productivity of 3.16% at 25 °C or 8.00% at 60 °C for solar energy conversion into H₂ at AM 1.5G, being one of the most efficient H₂-evolution catalysts for photocatalytic H₂O overall splitting.