Cesium salt of sodium 30-tungstopentaphosphate: An effective and green polyoxometalate for synthesis of gold nanoparticles along with decoration of titanium dioxide with gold nanoparticles for bleaching of malachite green

For the first time, capability of the cesium salt of sodium 30-tungstopentaphosphate, the so-called Preyssler's anion (CsP₅), as a green and eco-friendly polyoxometalate was investigated in the synthesis of gold nanoparticles and decoration of titanium dioxide with gold nanoparticles. Gold nanoparticles and nanocomposites were characterized by TEM, XRD, UV, and FTIR. TEM images showed that the gold nanoparticles have tubular and spherical shapes and particle size ranges from 10 to 25 nm. For gold-decorated titanium dioxide/Preyssler, a comparison between pure and amine-modified titanium dioxide showed higher loading of gold nanoparticles on amine-functionalized titanium dioxide. The performance of CsP₅ was compared with its pure acid (HP₅). Our findings showed that CsP₅, as a catalytic linker to bind onto titanium dioxide surface for reducing gold nanoparticles, renders decoration better than HP₅ in both pure and modified titanium dioxide. In addition, efficiency of the photocatalytic bleaching of malachite green by the synthesized nanocomposites was found to be excellent.