Shape-dependent photocatalytic hydrogen evolution activity over a Pt nanoparticle coupled g-C3N4 photocatalyst.

Cubic, octahedral and spherical platinum (Pt) nanoparticles (NPs) ex situ supported on a graphitic carbon nitride (g-C3N4) substrate are synthesized using a colloidal adsorption-deposition method for photocatalytic hydrogen evolution reactions. These Pt NPs of different shapes have similar sizes of around 10 nm but have different facets exposed. It is found that the visible-light-driven photocatalytic activities for the Pt/g-C3N4 hybrid photocatalysts follow the order as: cubic Pt/g-C3N4 < octahedral Pt/g-C3N4 < spherical Pt/g-C3N4, revealing the significant cocatalyst shape-sensitive photocatalytic activity in the Pt/g-C3N4 hybrids. This is mainly due to the different surface atomic structures of different exposed facets of Pt NPs, which lead to the disparity of active sites and adsorption energies in photocatalytic reactions.