Plasmonic Ag as electron-transfer mediators in Bi2MoO6/Ag-AgCl for efficient photocatalytic inactivation of bacteria

Solar-driven photocatalysis undoubtedly represents one of the most promising alternative water disinfection technologies, however, its practical application is still restrained by the fast recombination of carriers. To overcome this limitation, plasmon-induced photocatalytic processes have gained attention due to their extended optical absorption and enhanced charge separation when metal nanoparticles act as co-catalysts. In this work, to enhance the photocatalytic disinfection of Bi2MoO6/AgCl, the formation of plasmonic Ag nanoparticles as electron transfer mediators was promoted on the surface of Bi2MoO6 photocatalysts. Specifically, the co-modified Bi2MoO6/Ag-AgCl photocatalysts were synthesized via a two-step process involving the precipitation of AgCl and photo-reduction of Ag on the Bi2MoO6 surface. It was found that Bi2MoO6/Ag-AgCl photocatalysts exhibited higher photocatalytic disinfection activity under visible light irradiation than those of Bi2MoO6 and Bi2MoO6/AgCl. The photocatalytic mechanism of Bi2MoO6/AgCl could be attributed to the excellent synergistic effect of Ag and AgCl, where plasmonic Ag nanoparticles promote light absorption and work as electron-transfer mediators to transfer electrons from Bi2MoO6 to AgCl, meanwhile AgCl work as interfacial catalytic active sites to product free radicals based on the powerful characterizations, such as PL spectra, photoelectrochemical methodology and theoretical calculations. This work may provide new insights to employ synergistic effect of heterogeneous photocatalysts for improving the catalytic activities in water purification.