Efficient inactivation of bacteria in the sewage via a photocatalytic process represents a promising strategy for the efficient chemical utilization of solar energy. Herein, uniformly dispersed Fe atoms were embedded between layers of g-C3N4 photocatalysts (CNFx), which were facilely prepared by thermal treatment. The optimized photocatalyst (CNF100) first showed excellent photoactivity for killing a variety of bacteria (93.0% for E. coli, 93.9% for Salmonella, and 96.2% for S. aureus) under visible light irradiation. The superior activity can be attributed to the formation of shallow electron traps (Fe-N3) that can capture excitons of excited states, which promote the charge transfer and energy transfer process of activated adsorbed molecular oxygen, respectively, forming reactive oxygen species, improving separation efficiency of photoexcited electrons and holes, and the Fe-N3 traps can also be used as photosensitive sites to broaden the absorption range of visible light. This strategy of constructing shallow electronic traps lays a theoretical foundation for the design of new environmentally friendly and efficient water disinfectants.

Mn atoms and oxygen vacancies induce the formation of Ti–Mn–O3 sites by visible light-driven, which further regulates the surface potential, visible-light absorption, and carrier separation, resulting in superior H2 evolution.

Photocatalytic sterilization represents one of the promising strategies for efficient utilization of solar energy to remove hazardous materials, mainly based on the development of intrinsic materials with intact structures that actually cannot be absolutely remained under light irradiation but ignored in most cases. Herein, novel single titanium atoms anchored on g-C3N4 photocatalysts were facilely prepared by calcination of g-C3N4 with bis (cyclopentadienyl)dicarbonyl titanium. The introduction of single Ti atoms in g-C3N4 promoted photocatalytic efficiency by improving the separation efficiency of carriers with a broad visible-light-responsive range and reducing the energy barrier for the transfer of superoxide radicals to hydroxyl radicals. Especially, upon light -driven interaction with adsorbed O2, the photocatalyst coordination number could be remarkably regulated in situ from Ti-N6 to Ti-N4, which led to a more efficient generation of clean active substances in disinfectants (O2 center dot- and center dot OH). As a result, the single Ti catalyst showed superior activity in the photocatalytic disinfection of bacteria and excellent recyclability. The inactivation of E. coli for the CN-Ti50 sample was 91.2% under irra-diation for 30 min, which was 9.9 times that of pure g-C3N4. This in situ activation approach opens a new avenue for engineering efficient and energy-saving catalysts for water sterilization.