Selective Growth of Ni Tips on Nanorod Photocatalysts

Selective Growth of Ni Tips on Nanorod Photocatalyst

Perfect Photon-to-Hydrogen Conversion Efficiency

We report a record 100% photon-to-hydrogen production efficiency, under visible light illumination, for the photocatalytic water-splitting reduction half-reaction. This result was accomplished by utilization of nanoparticle-based photocatalysts, composed of Pt-tipped CdSe@CdS rods, with a hydroxyl anion–radical redox couple operating as a shuttle to relay the holes. The implications of such record efficiency for the prospects of realizing practical over all water splitting and solar-to-fuel energy conversion are discussed

Less Is More: The Case of Metal Cocatalysts

We provide evidence that for a multielectron reaction such as hydrogen reduction, the photocatalyst design should include only a single cocatalytic site per each segment of the semiconductor capable of light excitation. This is to ensure that intermediates are formed at close proximity. These findings are demonstrated by evaluating the efficiency for hydrogen production over a nanoparticle-based photocatalyst consisting of Pt-decorated CdSe@CdS rods. Rods decorated with a single Pt catalyst were found to be the most active for hydrogen production, with QE of 27%, while rods having two reduction sites reached QE of only 18% and rods with multiple sites showed very low activity. The advantage of using a single catalytic site became negligible when the rods were employed in catalyzing a single electron reaction. We believe the implications of this finding are of significance for the proper design of photocatalysts aimed at solar-to-fuel energy conversion

Molecular Metallocorrole–Nanorod Photocatalytic System for Sustainable Hydrogen Production

Solar-driven photocatalytic generation of hydrogen from water is a potential source of clean and renewable fuel. Yet systems that are sufficiently stable and efficient for practical use have not been realized. Here, nanorod photocatalysts that have proven record activity for the water reduction half reaction were successfully combined with molecular metallocorroles suitable for catalyzing the accompanying oxidation reactions. Utilization of OH−/⋅OH redox species as charge transfer shuttle between freely mixed metallocorroles and rods resulted in quantum efficiency that peaked as high as 17 % for hydrogen production from water in the absence of sacrificial hole scavengers. While typically each sacrificial scavenger is able to extract but a single hole, here the molecular metallocorrole catalysts were found to successfully handle nearly 300,000 holes during their lifespan. The implications of the new system on the prospects of realizing practical overall water splitting and direct solar-to-fuel energy conversion were discussed.Peer reviewe