Highly Active PtSn{110}-Excavated Nanocube Cocatalysts for Photocatalytic Hydrogen Production.

In photocatalytic hydrogen production via water splitting, noble metal alloy nanoparticles exposed to specific crystal facets can be highly effective cocatalysts in comparison with noble metal nanospherical particles. In this research, we have investigated, for the first time, the {110} facet-dependent efficiency of a PtSn nanocube cocatalyst for solar photocatalytic hydrogen production. Under identical conditions and with the same cocatalyst loading, the hydrogen production rate over excavated {110} facet-exposed PtSn nanocubes/CdS is 2 times higher than that of {100} facet-exposed PtSn nanocubes/CdS and 3.5 times higher than that of {100} facet-exposed Pt nanocubes/CdS. The quantum efficiency of photocatalytic hydrogen production over the {110} facet-exposed PtSn nanocubes/CdS can be as high as 86% at 420 nm, exceeding the previously reported efficiencies. Theoretical computations and experimental characterizations have revealed that excavated PtSn nanocubes exposed to high-energy {110} crystal facets are more favorable for hydrogen evolution reactions than other cocatalysts studied, leading to excellent photocatalytic performance. Tuning the exposed facets of a metal cocatalyst can greatly promote its photocatalytic activity. This work provides an alternative strategy for synthesizing highly active photocatalysts for water splitting/reducing.