Uniform Pt quantum dots-decorated porous g-C3N4 nanosheets for efficient separation of electron-hole and enhanced solar-driven photocatalytic performance.

Uniform Pt quantum dots-decorated porous g-C3N4 nanosheets (Pt/CN) are fabricated by a facile impregnation-ultrasonic-calcination method, using melamine as precursor. The as-prepared samples are evidently investigated by X-ray diffraction, UV-vis diffuse reflection spectra, N2 adsorption, transmission electron microscope, surface photovoltage spectroscopy and photoluminescence. The deposited Pt quantum dots with particle size of ∼5 nm are decorated on the surface of porous g-C3N4 nanosheets uniformly. The Pt/CN nanosheets show conspicuous solar-driven photocatalytic activity for splitting water to produce H2. The solar-driven photocatalytic hydrogen production rate of Pt/CN is up to ∼107 μmol h-1 g-1, which is about 5 times higher than that of pristine g-C3N4. The enhancement can be attributed to the porous structure offering adequate surface active sites and the efficient decoration of uniform Pt quantum dots on g-C3N4 nanosheets facilitating the separation of photogenerated electron-hole pairs, which is confirmed by surface photovoltage spectroscopy and photoluminescence. The strategy for fabricating Pt quantum dots-decorated g-C3N4 nanosheets offers new insights for constructing other high-performance quantum dot-semiconductor photocatalytic materials.