Characterization and Assessment of the Photo-catalytic Efficiency of Palladium/Silver Doped TiO&lt;sub&gt;2&lt;/sub&gt;Nanoparticles

Ao Aroh,Ki Omoniyi,Ce Gimba,Mt Yilleng,H Abba

doi:10.4314/jasem.v22i9.01

Abstract

The effect of modified TiO2with palladium, silver and co-dopant of palladium and silver on TiO2 with its photocatalytic efficiency were studied using X-ray diffraction (XRD) and Brunauer-Emmet –Teller (BET). The photocatalysts were prepared by sol immobilization method and characterized using XRD and BET techniques. The X-ray diffraction patterns of the dopants were found to be uniform with the standard P25 degussa TiO2. From the peak formation of anatase and rutile phases, it was found that the Pd/TiO2formed uniform matrix of anatase and rutile indicating that palladium ion disperses evenly on P25 degussa TiO2. The peak formation on Ag/TiO2 and Pd/AgTiO2shows the same uniform distribution of silver and palladium ion, only that foreign peak were observed on the formation of anatase and rutile because of impurity on silver. The crystalline size of the catalyst and full width at half maximum (FWHM) were also calculated at different angles of diffraction. The BET shows that the photocatalysts were mesoporous and is type IV isotherm. The high mesopore of the catalyst increases its photocatalytic activity, so also type IV isotherm. The BET analysis shows that the pore size distribution of the catalyst is between 2nm and 50nm which shows that the catalyst is mesoporous. It also gives high surface area with high volume and low pore size (crystalline size) which increases the photocatalytic efficiency. So co-doping of palladium and silver on TiO2 can serve as a strategy for design of high performance photocalysts for environmental benefits.Keywords: Brunauer-Emmet –Teller; co-doping; mesoporous; Pd/AgTiO2

Highlights

A photo-catalyst is defined as a substance that is activated by the absorption of photon and helps to accelerate a reaction without being consumed(Abhang et al, 2011).Titanium (IV) oxide photo-catalyst is one of the revolutionized technologies in the field of environmental purification and energy generation, and has found extensive application in heterogeneous photo-catalysis for removing organic pollutants from air, water, soil and in hydrogen production from photocatalytic water-splitting
The wide band gap limits the use of sunlight as excitation energy and the high rate of recombination of photo-generated electron hole pairs inTiO2 results in low photocatalytic efficiency (Ahmed et al, 2013)
The X-Ray Diffractometer (XRD) pattern of P25 degussa TiO2 indicated that Pd loaded on TiO2 surface almost

Summary

Introduction

A photo-catalyst is defined as a substance that is activated by the absorption of photon and helps to accelerate a reaction without being consumed(Abhang et al, 2011).Titanium (IV) oxide photo-catalyst is one of the revolutionized technologies in the field of environmental purification and energy generation, and has found extensive application in heterogeneous photo-catalysis for removing organic pollutants from air, water, soil and in hydrogen production from photocatalytic water-splitting. Anatase-titania is usually considered to be more active that rutile Though, the latter is a thermodynamically stable phase, and reveals a lower band gap than the anatase (Silva et al, 2009). Notwithstanding, TiO2photocatalyst is known to have some shortcomings in practical applications One of these is that TiO2 has activity when it is only under light of wavelength shorter than 388nm, because of its wide band gap (3.2eV) (Ge and Xu, 2006). The wide band gap limits the use of sunlight as excitation energy and the high rate of recombination of photo-generated electron hole pairs inTiO2 results in low photocatalytic efficiency (Ahmed et al, 2013). Various metals such as Pt, Au, Pd, Rb and Ag have been used as electron acceptors to separate the photo-induced hole/electron pair and promote interfacial charge-transfer process (Wu and Chen, 2004)

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