Gold Nanoparticle-Decorated Keggin Ions/TiO₂Photococatalyst for Improved Solar Light Photocatalysis

Abstract

We demonstrate a facile localized reduction approach to synthesizing a Au nanoparticle-decorated Keggin ion/TiO(2) photococatalyst for improved solar light photocatalysis application. This has been achieved by exploiting the ability of TiO(2)-bound Keggin ions to act as a UV-switchable, highly localized reducing agent. Notably, the approach proposed here does not lead to contamination of the resultant cocatalyst with free metal nanoparticles during aqueous solution-based synthesis. The study shows that for Keggin ions (phosphotungstic acid, PTA), being photoactive molecules, the presence of both Au nanoparticles and PTA on the TiO(2) surface in a cocatalytic system can have a dramatic effect on increasing the photocatalytic performance of the composite system, as opposed to a TiO(2) surface directly decorated with metal nanoparticles without a sandwiched PTA layer. The remarkable increase in the photocatalytic performance of these materials toward the degradation of a model organic Congo red dye correlates to an increase of 2.7-fold over that of anatase TiO(2) after adding Au to it and 4.3-fold after introducing PTA along with Au to it. The generalized localized reduction approach to preparing TiO(2)-PTA-Au cocatalysts reported here can be further extended to other similar systems, wherein a range of metal nanoparticles in the presence of different Keggin ions can be utilized. The composites reported here may have wide potential implications toward the degradation of organic species and solar cell applications.

Synthesis and characterization of Cu2O/Au and its application in catalytic reduction of 4-nitrophenol

“…1 [38][39][40][41]. Figure 2a presents the low-magnification TEM image of the as-prepared Cu 2 O sub-microspheres, which shows that the Cu 2 O are well-defined spheres, uniform and monodispersed with average diameter estimated to be about 300 nm and it can be seen the spheres exhibit rough surfaces.…”

“…Sodium borohydride (NaBH 4 ) is the most popular reducing agent for the reduction of amino nitro compounds for its many advantages such as safe to handle, no pressure apparatus requirement, easy to work at the experimental condition, rapid reduction and good selectivity in the reduction of nitro compounds. The reduction of 4-NP has been used by a number of researchers to investigate the catalytic activity of NPs [38][39][40].…”

Fine-Tuning the Antimicrobial Profile of Biocompatible Gold Nanoparticles by Sequential Surface Functionalization Using Polyoxometalates and Lysine

“…Mode of POM binding to the AuNPs Tyr was further studies by comparing the FTIR spectra arising from pristine POM molecules and AuNPs Tyr with that of AuNPs Tyr@PTA (Figure 3B) and AuNPs Tyr@PMA (Figure 3C). The Keggin structures of POMs (PTA - H 3 PW 12 O 40 and PMA - H 3 PMo 12 O 40 ) consist of a cage of either W or Mo atoms linked by O atoms with the P atom at the center of the tetrahedra [26-29]. Oxygen atoms form distinct bonds both in case of PTA (P–O, W–O–W, and W=O) and PMA (P–O, Mo–O–Mo, and Mo=O) within their Keggin structure, which have distinguishable infrared signatures.…”

Green Synthesis of Nanomaterials Using Biological Routes

“…The synthesis of metal nanoparticles especially that of noble metals is of enormous importance due to their interesting optical, electronic, catalytic, and sensing properties [5,[32][33][34][35][36][37][38][39]. Although solution-based chemical routes have dominated the field of nanomaterial synthesis, the recent past has seen an increasing trend in employing biological entities toward the synthesis of metal nanoparticles.…”