Photocatalytic reduction of Cr(VI) within mesoporous TiO2 templated and confined with chlorophyll

Abstract

Abstract Biomimetic light‐harvesting architecture has been proposed as an alternative for existing solar conversion systems. Chlorophyll‐sensitized TiO2 have been identified as promising catalyst for photocatalytic reduction system, but it is largely limited to complicated process for purification of chlorophyll and adding extra hole scavenger in system. In sharp contrast to conventional photosensitization methods in which the organic dyes were often adsorbed after photosensitization, herein mesoporous TiO2 incorporated with chlorophyll extract was synthesized in situ (TiO2/Chl). Interestingly, TiO2 incorporated with chlorophyll exhibited two distinct absorption bands around 407 and 668 nm which are closed to the characteristic absorption peak of chlorophyll. TiO2 incorporated with chlorophyll kept at 185°C for 1.5 hours (TiO2/Chl‐185) achieved a high photoreduction rate of 86.1% for the photocatalytic reduction of Cr(VI), which was approximately 29 and 20 times higher than that of TiO2 and TiO2 adsorbing chlorophyll (TiO2/ads Chl), respectively. The significant enhancement was due to the confinement of chlorophyll. This demonstrates that mesoporous TiO2 templated and confined with chlorophyll could offer a new approach for synergistic photoreduction of Cr(VI).

Keywords

• chlorophyll composite
• mesoporous TiO2
• nanoscale confinement
• photocatalytic reduction of Cr(VI)
• visible‐light photocatalysis