Visible‐Light‐Activated Photocatalytic Films toward Self‐Cleaning Membranes

Membranes are among the most promising means of delivering increased supplies of fit-for-purpose water, but membrane fouling remains a critical issue restricting their widespread application. Coupling photocatalysis with membrane separation has been proposed as a potentially effective approach to reduce membrane fouling. However, commonly used materials in photocatalysis limit use of low-cost sources such as sunlight due to their large bandgaps. There are few examples of in situ photocatalytic self-cleaning of membranes, with removal from the filtration system and ex situ illumination being more common. In this work, a visible-light-activated photocatalytic film prepared by nitrogen doping into the lattice of TiO2 is deposited on commercial ceramic membranes via atomic layer deposition. The synergy between membrane separation and redox reactions between organic pollutants and reactive oxygen species produced by the visible-light-activated layer offers a possibility for stable and sustainable membrane operation under in situ solar irradiation.