Malaysian Journal of Analytical Sciences Vol 21 No 1 (2017): 166 - 172

DOI: http://dx.doi.org/10.17576/mjas-2017-2101-19

 

 

 

CeO₂-TiO₂ FOR PHOTOREDUCTION OF CO₂ TO METHANOL UNDER VISIBLE LIGHT: EFFECT OF CERIA LOADING

 

(CeO₂-TiO₂ untuk Penurunan CO₂ kepada Metanol di bawah Radiasi Cahaya Nampak:Kesan Pemuatan Ceria)

 

Hamidah Abdullah^1,2*, Nur Aminatulmimi Ismail¹, Zahira Yaakob², Maksudur R. Khan¹,

Syarifah Abd Rahim¹

 

¹Faculty of Chemical and Natural Resources Engineering,

Universiti Malaysia Pahang, 26300, Kuantan, Pahang, Malaysia

² Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment,

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

 

*Corresponding author: hamidah@ump.edu.my

 

 

Received: 21 October 2015; Accepted: 14 June 2016

 

 

Abstract

A visible light-driven photocatalyst, CeO₂-TiO₂ catalyst with different ceria loading was synthesized by impregnation method between TiO₂ powder and cerium oxide nanoparticles slurry. The prepared catalyst samples were characterized by X-ray diffraction (XRD), surface area analysis, UV-vis absorption spectroscopy and photoluminescence spectroscopy (PL). The band gap of CeO₂-TiO₂ catalyst was found to be 2.15 – 2.4 eV. The band gap reduction clearly indicated the successful loading of CeO₂ on TiO₂. The photocatalytic activity was determined by measuring the photoreduction of CO₂ to methanol in aqueous solution under visible light. The effect of cerium loading in the range of 1 to 5 wt% on the photocatalytic activity was studied and 2 wt% CeO₂-TiO₂ was found to exhibit the maximum photoactivity of 18.6 µmol/g.catalyst after 6 hours irradiation. Results showed that the prepared photocatalyst is visible light active and may be used as effective catalyst in photoreduction of CO₂ to methanol.

 

Keywords:  metal oxide, photocatalyst, band gap, nanoparticles

 

Abstrak

Fotomangkin yang boleh diaplikasi di bawah radiasi cahaya nampak iaitu mangkin CeO₂-TiO₂ yang berbeza muatan ceria telah disintesis dengan kaedah impregnasi serbuk titanium dioksida dengan mendakan partikel nano cerium dioksida.  Ciri mangkin yang dihasilkan dikaji dengan menggunakan pembelauan sinar-X (XRD), analisis luas permukaan, UV-Vis spektrofotometer dan spektroskopi fotoluminesen (PL). Jurang tenaga mangkin CeO₂-TiO₂ adalah di antara 2.15 eV hingga 2.4 eV. Pengurangan jurang tenaga jelas menunjukkan  pemuatan CeO₂ ke atas TiO₂ telah berjaya. Aktiviti fotopemangkinan ditentukan melalui tindak balas penurunan gas karbon dioksida (CO₂) di dalam larutan akueus kepada metanol dan dijalankan di bawah radiasi cahaya nampak.  Kesan pemuatan 1 hingga 5 peratus berat cerium ke atas TiO₂ terhadap aktiviti fotopemangkinan  telah dikaji dan CeO₂-TiO₂ dengan 2 peratus berat cerium didapati menunjukkan fotosensitiviti maksimum iaitu penghasilan 18.6 µmol/g.mangkin selepas 6 jam radiasi. Hasil kajian menunjukkan bahawa fotomangkin yang dihasilkan adalah aktif di bawah cahaya nampak dan dijangka efektif untuk penurunan CO₂ kepada metanol.

 

Kata kunci:  logam oksida, fotomangkin, jurang tenaga, partikel nano

 

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