Hierarchical TiO2 nanorods with a highly active surface for photocatalytic CO2 reduction

Photocatalytic carbon dioxide reduction reaction (CO2RR) has been considered as one of most effective ways to solve the current energy crisis and environmental problems. However, the practical application of photocatalytic CO2RR is largely hindered by lock of efficient catalyst. Here, hierarchical titanium dioxide (TiO2) nanostructures with a highly active {001} surface were successfully synthesized by a facile approach from metal Ti powders. The obtained hierarchical TiO2 nanostructures were composed of TiO2 nanorods, which have a diameter about 5-10 nm and a length of several micrometers. It is found that these nanorods have exposed {001} facets. On the other hand, these hierarchical TiO2 nanostructures have a good light-harvesting efficiency with the help of TiO2 nanorods component and large specific surface area. Therefore, these hierarchical TiO2 nanostructures exhibit a much better activity for photocatalytic CO2 reduction than that of commercial TiO2 (P25). This high activity can be attributed to the synergistic effects of active surface, efficient charge transfer along nanorods and good light harvesting in the nanorod-hierarchical nanostructures.