Photocatalytic Applications in Artificial Photosynthesis

Readers are directed to spedfic reviews on the general topic of artifidal photosynthesis [156, 210-212] and we highlight here some aspects related to the role of the Ti02 component. 

It has been reported that titania-based catalysts induce artifidal photosynthesis, yielding single-carbon molecules in photocatalytic C02 reduction, such as CO, CH4, CH3OH, formaldehyde, and formic acid. Aqueous suspensions of titania-based catalysts were first used in photoelectrocatalytic C02 reduction [213]. Copper-Ti02 aqueous suspensions were found active in the photocatalytic C02 reduction to 

Zhou et al. obtained nitrogen-doped titanium dioxide replicas via a two-step infiltration process with natural leaves as templates [220]. The replicas inherited the hierarchical structures of the natural leaf at the macro-, micro-, and nanoscales. These materials showed enhanced light-harvesting and photocatalytic hydrogen evolution activities. The photocatalytic water splitting activity of the artificial leaf structures was eight times higher than that of titanium dioxide synthesized without templates. 

The extension of this approach to artificial leaves based on titanates, niobates, tantalates, metal nitrides and phosphides, metal sulfides, and other transition metal oxides appears possible and useful in order to enhance the photocatalytic efficiency. In addition, the construction of multicomponent systems such as Ti02-CdS or MoS2-CdSe for overall water splitting could also lead to further improvements. This 

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