Photocatalytic Hydrogen Evolution over Exfoliated Rh-Doped Titanate Nanosheets.

Various amounts of Rh-doped titanate nanosheets (TiNS:Rh(), where is doped amount) were prepared to develop a new nanostructured photocatalyst based on metal oxide compounds that can split water to produce H under sunlight. TiNS:Rh() was obtained by acid exchange, intercalation, and exfoliation of Rh-doped layered sodium titanate compound (NaTi Rh O). A new energy gap was found in the diffuse reflection spectrum of the TiNS:Rh() colloidal suspension solution; this new energy gap corresponds to electrons in the 4d level of Rh or Rh, which are doped in the Ti site. A photocatalyst activity of TiNS:Rh() for H evolution in water with triethylamine (TEA) as an electron donor was investigated. The appropriate amount of Rh doping can improve the photocatalytic activity of TiNS for H evolution from water using triethylamine (TEA) as a sacrifice agent. The reason was related to the rich state of Rh or Rh doped in the Ti site of TiNS. Doping Rh 1 mol % of Ti, TiNS:Rh(0.03) shows the H evolution rates up to 1040 nmol/h, which is about 25 times larger than that of nondoped TiNS under UV irradiation (>220 nm) and 302 nmol/h under near-UV irradiation (>340 nm). These results show that the development of new nanostructured photocatalyst based on Rh-doped titanate compounds that can produce H under near-UV irradiation present in sunlight was a success.