Fabricating acid-sensitive controlled PAA@Ag/AgCl/CN photocatalyst with reversible photocatalytic activity transformation

Achieving the intelligent controllability of the photocatalyst to the surrounding environment is a very meaningful work. Here, the polyacrylic acid (PAA) modified Ag/AgCl-40/CN composite was constructed to achieve an intelligent response of pH value. PAA exhibits hydrophilic properties at high pH value, increasing the adsorption capacity to tetracycline (TC) molecules. The morphology of PAA from contracted state to diastolic state, releasing the Ag/AgCl-40/CN catalyst. In addition, PAA modified Ag/AgCl-40/CN can prevent the loss of AgCl. The g-C₃N₄ nanosheets (CN) as a carrier enhance the dispersibility of the AgCl particles. The LSPR effects of Ag nanoparticles produce more electrons acting on photocatalytic degradation. On the results of experiment, the degradation of TC by PAA@Ag/AgCl-40/CN shows an excellent degradation activity when the high pH value. Photoluminescence spectroscopy and photocurrent demonstrate that carrier separation efficiency of PAA@Ag/AgCl-40/CN is higher than CN and Ag/AgCl-40/CN. The detection of the main active substances •O₂⁻ and h⁺, revealing a reasonable mechanism for the PAA@Ag/AgCl-40/CN hybrid system. This work provides a procedure to obtain smart materials that can switch photocatalytic processes.