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

Abstract 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 FeS ₂ to amplify CdS polarization for exceptional H ₂ photocatalytic generation. The spin‐polarized states amplified by the upshift energy levels of Fe 3 d and Cd 3 d 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 2 p from FeS ₂ and Cd 3 d of CdS are decreased by their electron transfer into the corresponding unoccupied orbits, respectively, performing Volmer‐Heyrovsky and Volmer‐Tafel paths for H ₂ 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 H ₂ at AM 1.5G, being one of the most efficient H ₂ ‐evolution catalysts for photocatalytic H ₂ O overall splitting.