Synergistically regulating d-band centers of heterojunction redox sites by ligand effect for photocatalytic H₂ evolution

Stiff transportation behaviors in kinetics for photo-excited charges from their generation sites to corresponding redox sites as well as subsequent large reaction overpotential of these charges with intermediates during splitting H₂O have not been solved yet, which extremely hinders solar photon energy conversion into H₂ (STH). Herein, CeO₂ nanowires-anchored Ni₂P nanoparticles were built to solve the above dynamical issues by synchronously modifying d-band centers (ε_d) with ligand effect. Photon-excited electrons and holes were separately propelled to Ni₂P as the reductive site and CeO₂ as the oxidative site within the spontaneously formed localized electric field for the dehydrogenation and coupling of active oxyhydrogen intermediates, respectively, characterized by in situ diffuse reflectance infrared Fourier transform spectroscopy and Hall effect tests. Consequently, a STH of 1.13% was achieved at room temperature under AM 1.5G irradiation. The study supplies a unique insight to enhance STH over heterojunction photocatalysts by synchronously tunning ε_d.