Micelle-mediated assembly of metals in Ag@MnOx/m-SiO2 for reinforced antimicrobial activity and photothermal water evaporation

Abstract

The increasing complexity of environmental pollution posed a higher requirement for the development of environment-governed functional materials. Herein, to achieve desired synergy and multiple functionalities of eco-friendly nanomaterials, a micelle-mediated metal assembly strategy was proposed to integrate plasmonic Ag nanoparticles into MnOx modified mesoporous silica hosts by metal-modified neutral dodecyl amine surfactant, correspondingly, a multifunctional mesoporous Ag@MnOx/m-SiO2 (AMSs) nanocomposite was obtained. The characterization results revealed that the introduction of Mn and alteration in the amount of Ag mediated the formation of a special mesostructure and nanometric morphology of the silica host. Bearing a low Ag loading (r.t. of Ag/Mn = 1/2), ultrafine Ag nanoparticles were embedded in the inner core of mesoporous silica nanospheres. While assembly with a higher Ag concentration affected the morphology of the obtained AMSs and resulted in rich Ag nanoparticles on the exterior surface of mesoporous silica. By this strategy, ultrafine Ag nanoparticles and well-dispersed amorphous MnOx species were coupled into the mesoporous silica to reach a special configuration and integrated functionality. The obtained AMSs-3 can effectively inactivate bacteria (E. coli, S. aureus, and P. aeruginosa) with a prolonged inhibitory effect, rapidly reduce harmful nitrophenol, as well as photothermally assist water evaporation (evaporation rate of 1.51 kg m−2 h−1, receiver efficiency of 87%). This work provides versatile environment-governing functional nanomaterials for both highly effective antimicrobial and environmental remediation.