Enhanced photocatalytic activity of transparent carbon nanowall/TiO2 heterostructures

The synthesis of novel tunable carbon-based nanostructure represented a pivotal point to enhance the efficiency of existing photocatalysts and to extend their applicability to a wider number of sustainable processes. In this letter, we describe a transparent photocatalytic heterostructure by growing boron-doped carbon nanowalls (B-CNWs) on quartz, followed by a simple TiO2 sol-gel deposition. The effect on the thickness and boron-doping in the B-CNWs layer was studied, and the photocatalytic removal of nitrogen oxides (NOx) measured. Our results show that TiO2, in the anatase form, was uniformly deposited on the carbon nanowall layer. The underlying carbon nanowall layer played a double role in the heterostructure: it both affects the crystallinity of the TiO2 and promotes the separation of the photoexcited electron-holes, by increasing the number of contact points between the two layers. In summary, the combination of B-CNWs with TiO2 can enhance the separation of the electron–hole photogenerated charges, due to the peculiar CNWs maze-like structure.