Template-assisted synthesis of porous Ag/ZnO photocatalyst from ZnS(HDA)_0.5/ZnO for enhanced degradation of organic pollutants and bacterial inactivation

A porous Ag/ZnO photocatalyst was synthesized for the efficient removal of organic pollutants and bacteria. First, porous ZnO nanosheets were obtained by thermally treating a inorganic-organic ZnS ethylenediamine (en)_0.5 template. Next, inorganic-organic ZnS hexamethylenediamine (HDA)_0.5/ZnO composite was then formed by adjusting the amounts of Na₂S and HDA. Silver was introduced into the structure through a cation-exchange method, followed by heat treatment to obtain the final Ag/ZnO photocatalys. To evaluate their photocatalytic performance, Orange II dye was used as a model organic pollutant, while Escherichia coli (E. coli) served as a microorganism for antibacterial inactivation. Compared to conventional 1 wt% Ag-loaded ZnO, the cation-exchange-derived porous Ag/ZnO-5t photocatalyst exhibited superior activity and achieving 96 % degradation of Orange II within 180 min and complete bacterial inactivation within 30 min under one sun irradiation. Additionally, the scavenger experiments showed that holes (h⁺) are the leading active species in the degradation process, while hydroxyl radicals (•OH) play a minor role. The enhanced photocatalytic performance can be attributed to the porous structure, increased surface area, and reduced charge recombination.