Synthesis of MoS2/P-g-C3N4 nanocomposites with enhanced visible-light photocatalytic activity for the removal of uranium (VI)

The photocatalytic is a safe, efficient, and environmentally friendly technology for uranium (VI) removal. In this study, MoS2 and P doped g-C3N4 nanocomposites (MPCN) were obtained by ultrasonic chemical method, and further characterized by XRD, SEM, TEM, XPS and several photoelectrochemical techniques. The introduction of MoS2 and incorporation of P atoms could increase visible light absorption and accelerate the interfacial charge transfer of MPCN. The MPCN containing 3% MoS2 (3% MPCN) exhibited the highest photocatalytic performance, resulting in a reduction rate of 0.1265 ​min−1, which is 5.6 times higher than that of pure g-C3N4. Furthermore, the reduction of U(VI) was activated by both photoinduced electrons and •O2- radicals, and the reduction products was confirmed as (UO2) O2·2H2O species. This element doped heterojunction photocatalyst and the mechanism of uranium photoreduction under air condition may bring new insight for radionuclides treatment. The 3% MPCN exhibited excellent photocatalytic reduction activity for U(VI) in the air atmosphere. The light absorption region could be expanded, and the recombination of charges could be effectively suppressed by doping element P and combining with MoS2. In addition, the reduction products were confirmed as (UO2) O2·2H2O species, which activated by both photoinduced electrons and •O2- radicals. [Display omitted] •MPCN was modified by element doping and heterostructure constructing.•Both P element doping and MoS2 constructing could alter the electronic property of g-C3N4.•MPCN could highly reduce U(VI) under background electrolytes.•The photo-reduced sediments were confirmed to (UO2) O2·2H2O species.