Controllable growth of silver nanoparticles on titanium dioxide/nitrogen-doped carbon nanofiber/molybdenum disulfide: Toward enhanced photocatalytic-activating peroxymonosulfate performance and “memory catalysis”

Abstract

The combination of photocatalysis and activating peroxymonosulfate (PMS) can generate more active species and degrade pollutants more efficiently. The introduction of “memory catalysis” in the photocatalytic-activating PMS system can further improve the catalytic degradation ability in the dark environment, because the stored electrons (e−1) during photocatalytic process can release in darkness to continue the degradation. In this paper, molybdenum disulfide (MoS2) nanosheets on titanium dioxide/nitrogen-doped carbon nanofibers (T/NC/MoS2 NFs) were prepared by electrospinning and hydrothermal treatment, and then silver (Ag) nanoparticles were deposited by photodeposition (PD) or dark deposition (DD) to form T/NC/MoS2@Ag NFs-PD and T/NC/MoS2@Ag NFs-DD, respectively. The influences of the two samples on the degradation of tetracycline (TC) and “memory catalysis” in photocatalytic-activating PMS systems were explored. The results show that T/NC/MoS2@Ag NFs-DD can remove TC more efficiently and reduce energy consumption. This is because the DD technology can effectively inhibit the growth and aggregation of Ag nanoparticles, thereby improving the e−1 storage capacity and the separation of photogenerated e−1 and holes (h+). Under outdoor solar irradiation, T/NC/MoS2@Ag NFs-DD showed excellent stability and high efficiency in catalytic degradation of a variety of organic pollutants. This study provides a new strategy to realize the efficient and energy-saving degradation of organic pollutants.