Sonochemical synthesis and characterization of Ho2Sn2O7/Er2Sn2O7 nanocomposites and their application as photocatalyst for degradation of water-soluble organic pollutants under UV light

[Display omitted] •Sonochemical synthesis of Ho2Sn2O7, Er2Sn2O7 and Ho2Sn2O7/Er2Sn2O7 nanocomposites.•First study on synergetic effects between Ho2Sn2O7 and Er2Sn2O7 nanostructures.•Ho2Sn2O7/Er2Sn2O7 nanocomposites degraded EBT about 95.34 %.•A plausible mechanism has been proposed by radical trapping experiments. We examined the bimetallic stannate Ho2Sn2O7/Er2Sn2O7 nanosized semiconductor as a new material for reducing organic pollutants in drinking water to further enhance the photo-catalytic efficiency of the nanophoto-catalysts. A simple sonochemical method, followed by calcination at 900 °C, was employed to fabricate the novel Ho2Sn2O7/Er2Sn2O7 nanocomposites, in addition to pure Ho2Sn2O7 and Er2Sn2O7 nanoparticles. The results of the X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements revealed a stable connection between cubic Ho2Sn2O7 and cubic Er2Sn2O7 nano-semiconductors in composite nature, with particle dimensions between 40 and 120 nm. According to Brunauer-Emmett-Teller (BET) analysis, the specific surface area of Ho2Sn2O7/ Er2Sn2O7 nanocomposites was found as 19.95 m2 g−1. Ho2Sn2O7/Er2Sn2O7 nanocomposites were compared in terms of their photo-degradation efficiency with pure Ho2Sn2O7 and Er2Sn2O7 nanoparticles under UV light to eliminate a variety of anionic and cationic synthetic dyes. In this study, the effects of nano-catalyst type, pollutant type, pollutant concentration, catalyst dosage, and scavenger parameters were considered on the UV-assisted catalytic ability of stable semiconductors. For the degradation of Eriochrome black T (EBT) pollutant, Ho2Sn2O7/Er2Sn2O7 nano-products with a degradation efficiency of 95.34 % were suitable candidates for UV-assisted catalyst activity. In the present study, it was shown that a novel simultaneous coupling between Ho2Sn2O7 and Er2Sn2O7 nanostructures with optical band gaps of 3.90 and 3.92 eV can substantially reduce the recombination of photogenerated carriers and therefore improve photocatalytic efficiency.