Angstrom-confined catalytic water purification within Co-TiOx laminar membrane nanochannels

The freshwater scarcity and inadequate access to clean water globally have rallied tremendous efforts in developing robust technologies for water purification and decontamination, and heterogeneous catalysis is a highly-promising solution. Sub-nanometer-confined reaction is the ultimate frontier of catalytic chemistry, yet it is challenging to form the angstrom channels with distributed atomic catalytic centers within, and to match the internal mass transfer and the reactive species' lifetimes. Here, we resolve these issues by applying the concept of the angstrom-confined catalytic water contaminant degradation to achieve unprecedented reaction rates within 4.6 angstrom channels of two-dimensional laminate membrane assembled from monolayer cobalt-doped titanium oxide nanosheets. The demonstrated degradation rate constant of the target pollutant ranitidine (1.06 ms(-1)) is 5-7 orders of magnitude faster compared with the state-of-the-art, achieving the 100% degradation over 100 h continuous operation. This approach is also similar to 100% effective against diverse water contaminates with a retention time of <30 ms, and the strategy developed can be also extended to other two-dimensional material-assembled membranes. This work paves the way towards the generic angstrom-confined catalysis and unravels the importance of utilizing angstrom-confinement strategy in the design of efficient catalysts for water purification.

Automated summary

The global shortage of freshwater and inadequate access to clean water have led to the development of efficient technologies for water purification. Heterogeneous catalysis is a highly promising solution and sub-nanometer-confined reactions have been found to achieve unprecedented reaction rates. This study successfully demonstrates the degradation of water contaminants at an incredibly fast rate using a two-dimensional laminate membrane assembled from cobalt-doped titanium oxide nanosheets.