Malaysian Journal of Analytical Sciences Vol 22 No 5 (2018): 807 - 816

PHOTOCATALYTIC DEGRADATION OF PHENOL DERIVATIVES OVER SILVER SUPPORTED ON MESOPOROUS TITANIA NANOPARTICLES

(Degradasi Fotomangkin Daripada Terbitan Fenol Ke Atas Perak Disokong Pada Nanopartikel Titania Berliang Meso)

Nur Farhana Jaafar¹* and Aishah Abdul Jalil^2,3

¹School of Chemical Sciences,

Universiti Sains Malaysia, 11800 USM Penang, Malaysia

²Centre for Hydrogen Energy, Institute of Future Energy

³Department of Chemical Engineering, Faculty of Chemical and Energy Engineering

Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia

*Corresponding author: nurfarhana@usm.my

Received: 15 May 2018; Accepted: 23 July 2018

Abstract

In this study, the potential of silver supported on mesoporous titania nanoparticles (Ag-MTN) as visible-light-driven photocatalyst was investigated for the degradation of phenol derivatives. Characterisation results illustrated that the presence of Ag reduced the band gap of MTN and increased the number of oxygen vacancies (OV) and Ti³⁺ site defect (TSD). The presence of both properties is among the important factors that need to be considered for catalyst properties in order to achieve effective photocatalytic degradation under visible light. The photoactivity of the catalyst was also significantly influenced by the presence of Ag, which acted as an electron trap that enhanced electron-hole separation. The ability of Ag-MTN to degrade phenol derivatives [phenol (Ph), 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-diCP), and 4-acetamidophenol (4-AcePh)] was compared with commercial TiO₂ and MTN. The percentage degradation of phenol derivatives was in the following order: TiO₂ < MTN < Ag-MTN. This indicated that the presence of Ag in MTN effectively enhanced the photoactivity of MTN towards the degradation of phenol derivatives.

Keywords: Ag-MTN catalyst, electron trapper, visible light, phenol derivatives

Abstrak

Dalam kajian ini, potensi perak disokong pada nanopartikel titania berliang meso (Ag-MTN) sebagai fotomangkin-pemacu-cahaya nampak telah disiasat bagi degradasi terbitan fenol. Keputusan pencirian menunjukkan kehadiran Ag mengurangkan luang jalur MTN dan meningkatkan bilangan kekosongan oksigen (OV) dan permukaan Ti³⁺ cacat (TSD). Kehadiran kedua-dua sifat adalah antara faktor penting yang perlu dipertimbangkan bagi sifat mangkin bagi mencapai degradasi fotomangkin yang efektif di bawah cahaya nampak. Fotoaktiviti bagi mangkin juga sangat dipengaruhi dengan kehadiran Ag di mana bertindak sebagai perangkap elektron yang meningkatkan pemisahan elektron-lubang. Keupayaan Ag-MTN untuk degradasi terbitan fenol [fenol (Ph), 2-klorofenol (2-CP), 2,4-diklorofenol (2,4-diCP) dan 4-asetamidofenol (4-AcePh)] telah dibandingkan dengan TiO₂ komersial dan MTN. Peratusan degradasi bagi terbitan fenol telah mengikuti susunan: TiO₂ < MTN < Ag-MTN. Ini menunjukkan kehadiran Ag dalam MTN berkesan meningkatan fotoaktiviti bagi MTN terhadap degradasi terbitan fenol.

Kata kunci: mangkin Ag-MTN, perangkap elektron, cahaya nampak, terbitan fenol

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