Water
oxidation process is a pivotal step of photosynthesis and
stimulates the progress of high-performance catalysts for renewable
fuel production. Despite the performance benefit of cocatalysts, defect
engineering holds promise to settle inherent limitations of semiconductors
aiming at sluggish water oxidation. Here, we modify the in
situ growth pathway of monoclinic BiVO4 (m-BiVO4) on reduced graphene oxide (rGO), constructing abundant surface
oxygen vacancies (OV)-incorporated m-BiVO4/rGO
heterostructure toward water oxidation reaction under visible light.
Owing to the OV in the m-BiVO4 component, a
vacancy-related defect level allows more electrons to be photoexcited
by low-energy photons to cause the electron transition, boosting photoabsorption
as well as photoexcitation. Besides, the OV can reinforce
surface adsorption and reduce the dissociation energy of water molecules.
Particularly because of the synergy of OV and cocatalyst
rGO, the OV functions as electron-trapped sites to facilitate
the carrier separation; the rGO not only receives electrons from m-BiVO4 promoted by internal electric field over Mott–Schottky
heterostructures but also spurs further electron diffusion along a
highly conductive carbon network. These merits enable the OV-incorporated m-BiVO4/rGO heterostructure with an over
209% growth in O2 yield relative to the counterpart. The
increased performance is also validated by the significant rise of •OH radicals and •O2
– radicals. The current work paves a novel avenue for
the integration of defect engineering and cocatalyst coupling in artificial
photosynthesis.
The bottleneck for water splitting to generate hydrogen fuel is sluggish water oxidation. Even though the monoclinic-BiVO4 (m-BiVO4)-based heterostructure has been widely applied for water oxidation, the carrier recombination on...
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