Interplay of adsorption, photo-absorption, electronic structure and charge carrier dynamics on visible light driven photocatalytic activity of Bi2MoO6/rGO (0D/2D) heterojunction

In the present research Bi2MoO6(BMO) QDs (0D) and reduce graphene oxide nanosheet (2D) (BMO/rGO)(0D/2D) heterojunction with different weight ratio of GO nanosheet were synthesized using facile method. XRD, UV-vis spectroscopy, XPS, FTIR, BET, PL, TRPL, TEM/HRTEM, ESR and photoelectrochemical (PEC) measurements were used for the characterization and understanding the enhancement effect on photoactivity of the synthesis photocatalyst. The BMO (0D) QDs provide more active sites and short diffusion length of photogenerated charges. Whereas, 2D rGO nanosheet presents complementary surface area to allow the formation of distinct heterojunction with majority of the 0D QDs by preventing agglomeration of particles and excellent conductivity. TEM images explicitly showed the uniform distribution of 0D BMO particles of size 8-10 nm over 2D rGO which lead to formation of distinct Schottky junction. These exclusive properties of 0D/2D heterojunction result in effective degradation of organic pollutants such as Rhodamine-B dye, p-nitrophenol a phenol group and acetaminophen a pharmaceuticals compound with 100 %, 94 % and 87 % in 180 min; and degradation rate achieved was 9.35, 8.60 and 7.53 as compared to 0D BMO QDs under simulated solar light irradiation. The scavenging experiments revealed that h(+) and O-2(center dot-) radicals are main reactive species involved in the photodegradation along with contribution from photogenerated e(-). The increased photocatalytic efficiency is ascribed to enlarge solar light absorption, increased adsorption, increased surface area, conductivity with substantial contribution of photo-induced charge separation and transfer in BMO/rGO (0D/2D) heterojunction.