Highly Photoactive Titanium Dioxide Supported Platinum Catalyst: Synthesis Using Cleaner Ultrasound Approach

Shital B Potdar,Shirish H Sonawane,Sivakumar Manickam,Bvs Praveen,Chao-Ming Huang

doi:10.3390/catal12010078

Abstract

Catalysts increase reaction rates; however, the surface area to volume ratio of catalysts has a vital role in catalytic activity. The noble metals such as platinum (Pt) and gold (Au) are expensive; despite this, they have proven their existence in catalysis, motivating the synthesis of supported metal catalysts. Metal catalysts need to be highly dispersed onto the support. In this investigation, an ultrasound approach has been attempted to synthesise highly photoactive titanium dioxide (TiO2) nanoparticles by the hydrolysis of titanium tetraisopropoxide in an acetone/methanol mixture. To enhance its photocatalytic activity, TiO2 was doped with Pt. The synthesised photocatalyst was characterised by techniques such as particle size analysis (PSA), XRD, FE-SEM, TEM, and EDX. The enhancement in the surface characteristics of Pt-doped TiO2 compared with bare TiO2 support was confirmed with Brunauer–Emmett–Teller (BET) analysis. The enhanced surface area and uniformity in particle size distribution at the nanoscale level were due to the effects of ultrasonic irradiation. The obtained results corroborated the size and composition of the synthesised catalysts. The size of the catalysts is in the nanometre range, and good dispersion of Pt catalysts over the TiO2 support was observed. The UV-Visible spectroscopy analysis was performed to study the optical properties of the synthesised TiO2 and Pt/TiO2 photocatalysts. An increase in the absorbance was noted when Pt was added to TiO2, which is due to the decrease in the band gap energy.

Highlights

Photocatalysis is a technique that harnesses the available abundant solar energy; in it, a photon drives a chemical reaction in the presence of a catalyst
This study aims to synthesise anatase phase Pt-doped TiO2 NPs with a particle size less than 20 nm using an ultrasound approach
A photoactive TiO2 catalyst was synthesised with an ultrasound approach to improve the photocatalytic performance of TiO2, and it was doped with a noble metal Pt

Summary

Introduction

Photocatalysis is a technique that harnesses the available abundant solar energy; in it, a photon drives a chemical reaction in the presence of a catalyst. Titanium dioxide (TiO2) is a widely used photocatalyst, considering its good catalytic activity, high stability, low cost, and suitable band gap energy [3,4], and is beneficial in many applications such as oxidation reactions [5], solar cells [6], hydrogen production [7], water treatment [8,9], and degradation of pollutants [10]. Various dopants are impregnated into TiO2 to extend the sensitivity in the visible spectral range [11]. This process helps in minimising the surface charge transfer [12]. The sonochemical technique provides local temperatures of more than 5000 K, pressures more than 20 MPa, and a very high cooling rate during cavitation bubble collapse, causing special and unique properties for NPs [31]

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