Crystal strain engineering boosting carrier transfer behavior and synergistically activating surface sites of CeO2/MoS2 for H2O chemisorption and its conversion to H2

The decreased reaction activation energy and energetic carrier transfer kinetics behavior for H 2 O overall splitting concerning with the conducive chemisorption, and oriented conversion of *H and *OH are significantly important for efficiency and separation of H 2 generation. Herein, the concerns are addressed with crystal strain engineering induced by regulating Mo S and Ce O bonding lengths of CeO 2 /MoS 2 hetero photocatalysts to boost carrier transfer behavior and synergistically activate surface sites for eminent H 2 photocatalytic evolution. Ultrafast spatiotemporal atomic scale characterizations verify that CeO 2 /MoS 2 hetero photocatalysts endow an amplified polarization field pointing from the hexagonal MoS 2 {002} to cubic-phase CeO 2 {200} with an enlarged intensity to ~2.22 times, so prolonging the lifetime of charge carrier up to ~457 % on surface sites. Also, Mo 3 d and Ce 3 d as exposed surface redox sites by extending Mo S and Ce O promote chemisorption of *H and *OH, respectively, along with activation energy of H 2 O splitting down to ~73 %. Efficiencies for solar to H 2 from 1.30 % at 25 °C to 3.53 % at 60 °C under AM 1.5G are achieved, with the release of many H 2 bubbles. Our study highlights crystal strain engineering to synergistically regulate charge transfer behavior and surface site activation for photocatalytic H 2 production efficiency and releasing.