Large-scale synthesis of carbon dots/TiO₂ nanocomposites for the photocatalytic color switching system

Abstract

In view of the easy control and contactless spatial nature of light, the photoreversible color switching system has attracted tremendous attention.

Doping and Surface Modification of Carbon Quantum Dots for Enhanced Functionalities and Related Applications

“…The CQDs due to their notable merits in superior electron transfer ability, low toxicity, stable fluorescence, and high chemical stability have made their mark as potential light‐harvesting materials. [ 284,327,328 ] To further improve and extend their functions, modified CQDs are incorporated in the composites, leveraged by their nanoscale size, and high dispersion. The surface groups on CQDs facilitate their easy blending with other components forming nanocomposites.…”

Carbon Dots: An Emerging Smart Material for Analytical Applications

“…Upon UV-irradiation, the blue colouration of the methylene blue dyes with the CDs/TiO 2 nanocomposite could be photobleached within one minute to colourless state. With visible light irradiation, the original blue colour was fully recovered within 20 min [ 121 ].…”

Photoreductive BiOCl Ultrathin Nanosheets for Highly Efficient Photocatalytic Color Switching

“…Photochromic organic–inorganic hybrid materials that combine the advantages of organic and inorganic materials therefore open a new pathway to improve their photochromic properties. − In particular, we have recently developed a new type of hybrid photocatalytic color switching system (PCSS) that integrates the titanium dioxide nanoparticles with photoreductive activity and color-switchable redox materials, such as methylene blue (MB) and prussian blue . The key strategy of the PCSS is to bind capping ligands (such as Pluronic copolymer) , or create oxygen vacancies , in the TiO 2 nanoparticles as sacrificial electron donors (SEDs) to scavenge the photogenerated holes during ultraviolet (UV) illumination, endowing TiO 2 nanoparticles photoreductive activity to trigger photocatalytic color switching. For the hybrid TiO 2 /MB system, the photogenerated holes from TiO 2 nanoparticles are captured by SEDs during UV illumination, and the surviving photogenerated electrons rapidly reduce MB to colorless leuco MB (LMB). , The colorless system can recover the color rapidly by oxidizing LMB in ambient air conditions upon visible-light illumination, enabling reversible color switching .…”

“…For the hybrid TiO 2 /MB system, the photogenerated holes from TiO 2 nanoparticles are captured by SEDs during UV illumination, and the surviving photogenerated electrons rapidly reduce MB to colorless leuco MB (LMB). , The colorless system can recover the color rapidly by oxidizing LMB in ambient air conditions upon visible-light illumination, enabling reversible color switching . The PCSS based on photocatalytic reduction of color-switchable redox dyes is particularly appealing owing to its advantages such as rapid photoresponse, excellent repeatability, nontoxicity, and low cost. ,, However, the photoreductive catalysts developed in the new PCSSs have been mainly limited to TiO 2 -based photocatalysts, which greatly hinder their broad applications. It has remained a significant challenge to develop various photoreductive semiconductor photocatalysts to enrich the PCSS mainly because the insights in realizing photoreductive activity are largely lagged.…”