One‐Step Solvothermal Synthesis of a Carbon@TiO2 Dyade Structure Effectively Promoting Visible‐Light Photocatalysis

The development of sunlight harvesting chemical systems to catalyze relevant reactions, i.e., water splitting, CO 2 fi xation, and organic mineralization, is the key target in artifi cial photosynthesis but remains a diffi cult challenge. Titanium dioxide (TiO 2 ) has been widely used as a photocatalyst for solar energy conversion and environmental applications because of its low toxicity, abundance, high photostability, and high effi ciency. [ 1–4 ] However, the application of pure TiO 2 is limited, because it requires ultraviolet (UV) light, which makes up only a small fraction ( < 4%) of the total solar spectrum reaching the surface of the earth. Therefore, over the past few years, considerable efforts have been directed towards the improvement of the photocatalytic effi ciency of TiO 2 in the visible (vis)-light region. [ 5–7 ] This has been mainly achieved by introducing various dopants into the TiO 2 structure which can narrow the bandgap. The initial approach to dope TiO 2 materials was achieved using transition metals ions such as V, Cr, or Fe. [ 6 , 8–10 ] However, such metal doped materials lack the necessary thermal stability, exhibit atom diffusion and a remarkably increased electron/hole recombination of defect sites, which results in a low photocatalytic effi ciency. [ 11 ] Non-metal doping has since proved to be far more successful and has been extensively investigated. Thus, numerous reports on TiO 2 doped with B, F, N, C, S, or I have demonstrated a signifi cant improvement of the visible-light photocatalytic effi ciency. [ 4 , 12–16 ]