Co<sub>3</sub>O<sub>4</sub> Nanocrystals Coupled with Co-Doped TiO<sub>2</sub> Nanobelts as a Synergistic Photocatalyst for Efficient Photoconversion of CO<sub>2</sub> and H<sub>2</sub>O to Solar Fuels
Qiang Wang, Li Li, Yao Chai, Yuting Hu, Jun Liang
Abstract
Semiconductor-based photocatalytic technology for CO 2 reduction to produce fuels is a key toward developing new sustainable energy sources, but this technology remains a huge challenge. Herein, a p–n heterojunction photocatalyst composed of Co-doped TiO 2 nanobelts (Co–TiO 2 NBs) coupled with Co 3 O 4 nanoparticles (NPs) is designed through a two-step operation of hydrothermal ion exchange and medium temperature calcination. Characterization of the product demonstrates that Co 3 O 4 NPs are intimately embedded on the surface of Co–TiO 2 NBs, and they provide an ideal heterointerface with strong electron interaction. As compared to the single-phase TiO 2 NBs and Co 3 O 4 NPs, the Co 3 O 4 /Co–TiO 2 nanocomposite exhibits significantly improved photocatalytic performance for the conversion of CO 2 to H 2 O under simulated solar irradiation. It is shown that the p–n junctions constructed by p-type Co 3 O 4 NPs and n-type Co–TiO 2 NBs can effectively promote the transfer of photogenerated charges at the interface and improve the adsorption of CO 2 molecules, thus leading to a remarkable enhancement in photocatalytic CO 2 reduction activity.