Photocatalytic Hydrogen Generation by CdSe/CdS Nanoparticles

The photocatalytic hydrogen (H-2) production activity of various CdSe semiconductor nanoparticles was, compared including CdSe and CdSe/CdS quantum dots ('QDs), CdSe quantum rods (QRs), and CdSe/CdS dot-in-rods (DIRs). With equivalent photons absorbed, the H-2 generation activity orders as CdSe QDs >> CdSe QRs > CdSe/CdS QDs > CdSe > CdSe/Cds, which is surprisingly the opposite of the electron hole separation efficiency. Calculations of photoexcited surface charge densities are positively correlated with the H-2 production rate and suggest the size of the nanoparticle plays a critical role in determining the relative efficiency of H-2 production.