Photocatalysis procedure under solar light has exceptionally attracted and interested of researchers because it has the ability of splitting the water molecules and decomposing the organic contaminants (Miao, Pan et al. 2013, Phuruangrat, Putdum et al. 2015, Peng, Ye et al. 2021, Ramasamy, Jeyadharmarajan et al. 2021). Photocatalysis based on visible light has accounted for roughly 43% of solar energy, while UV radiation has accounted for just 5%. As a result, the development of new semiconductor-based materials is important in the field of Photocatalysis (Zhang, Wang et al. 2010). Various semiconductor-based photocatalysts, such as Bi-based (Dai, Qin et al. 2016), Ag-based (Du, Yang et al. 2021), In-based (Guo, Zhang et al. 2014), Ti-based (Guo, Zhou et al. 2019), and Cu-based (Luo, Steier et al. 2016), have been extensively studied during the last decade which related to chemical stability, high oxidized activity, non-toxicity and low prices (Asahi, Morikawa et al. 2001). Thoroughly traditional studies of TiO2 demonstrated its excellent activities and stabilities, but the technical implementation appeared to be constrained by certain parameters(Nakata and Fujishima 2012). Although the TiO2-based materials are represented the most important photocatalysts, the band gap of titania (anatase) is 3.2 eV and it absorbs only UV light (< 450nm) which lower the efficacy of using Solar energy and accounts for about 4% of the sunlight (Madhusudan, Yu et al. 2012, Liang, Yang et al. 2013, Phuruangrat, Jitrou et al. 2013, Xiao, Hu et al. 2013, Wang, Zheng et al. 2016). Cu2O is excellent for water splitting due to own conduction band negatively enough to reduction H2O to H2, however, it has high electron–hole pair recombination rate (Wang, Zheng et al. 2016). Recently, photocatalysts-based bismuth oxide for visible light activity include bismuth oxide (Xiao, Hu et al. 2013), bismuth molybdate (Phuruangrat, Jitrou et al. 2013), bismuth tungstate , bismuth subcarbonate (Madhusudan, Yu et al. 2012), and bismuth vanadate (Rahman, Haque et al. 2019), have extraordinarily studied to photodegradation due to own excellent activity.
Bi2MoO6 was discovered to be particularly interesting due to its physical properties for use as a dielectric material, gas sensors, ionic conductors, luminescent material, and photocatalyst. Because the Bi2MoO6 has deep valence band therefore it has strong oxidative potential as well as reductive potential in conduction band. The strong oxidative potential can directly degrade organic pollutants while the electron in conduction band produce superoxide (Galván, Castillón et al. 1999, Miao, Pan et al. 2013).
The Bi2MoO6, as an n-type semiconductor, with 2.6–2.9 eV, has been attracted for many previous papers as excellent photocatalyst (Zhao, Liu et al. 2016). the crystal structure is layers of perovskite (Am−1BmO3m+1) and bismuth oxide (Bi2O2 2+), which are stacked together and have excellent photocatalytic activity when exposed to visible light because it has spatial photoinduced charge separation, which have been extensively investigated as potential catalysts for accelerating the decomposition of organic pollutants such as phenol, rhodamine B (RhB), methylene orange (MO) n-butene, and methylene blue by converting them into CO2 and H2O via photogenerated electron-hole pairs (Dumrongrojthanath, Thongtem et al. 2015, Meng and Zhang 2017).
The pH-synthesis solution, in particularly Bismuth compound, is considered having significant influence on formation the composition and morphologies of the photocatalysis(Deng, Wang et al. 2005, Jin, Ye et al. 2015). Based on above details, we have adopted strategy to control the form and morphology of Bismuth Molybdate by adjust pH, the reaction has carried out by hydrothermal and the photocatalytic activities were tested for photodegrade dye and phenol.