Room Temperature Synthesis of Ceria by the Assisted of Cationic Surfactant and Aging Time

Abstract

This paper presents the synthesis of rare earth cerium(IV) oxide (ceria) via simple precipitation method under room temperature. The two aims of this research are to: (i) synthesise a ceria-based material using simple process and chemicals and (ii) modify the ceria-based material with environmentally friendly elements. In this study, cerium nitrate hexahydrate and sodium hydroxide were utilised as the precursor and precipitant, respectively, to attain desired crystallite size and shape, at a fixed reaction pH of 12. Besides that, common cationic surfactant, cetyl-tri-methyl-ammonium bromide (CTAB), was used to enhance ceria-based material's coveted properties. Furthermore, addition of surfactant and aging time (30 minutes, and 5, 10, 20, and 30 days) were also examined. Findings showed that as aging time increased, crystallite size decreased and production of large agglomerations were not observed. Then, optimum aging time was applied for synthesis of ceria material and modified ceria material, FeCeO 2 /TiO 2 , via impregnation method. These materials were subjected to X-ray diffraction (XRD), CO 2 -TemperatureProgrammed Desorption (CO 2 -TPD), and Field Emission Scanning Electron Microscopy (FESEM) to investigate the mutual effect of surfactant addition and aging time.Keywords: cationic, ceria, crystallite, precipitating, surfactant Abstrak Kajian ini menggambarkan sintesis salah satu unsur nadir bumi iaitu cerium(IV) oksida (ceria), melalui kaedah pemendakan pada suhu bilik. Matlamat kajian ini ialah: (i) sintesis bahan berasaskan ceria menggunakan proses dan bahan kimia yang mudah dan (ii) mengubahsuai bahan berasaskan ceria dengan penambahan unsur-unsur mesra alam. Dalam kajian ini, cerium nitrat heksahidrat dan natrium hidroksida telah digunakan sebagai bahan pemula dan agen pemendakan, supaya saiz dan bentuk yang dikehendaki dapat diperolehi pada pH yang telah ditetapkan iaitu pH 12. Selain itu, bahan tipikal surfaktan kation, cetil-tri-metilammonium bromida (CTAB), telah digunakan untuk memudahkan penghasilan bahan berasakan ceria dengan sifat-sifat yang dikehendaki. Di samping itu, penambahan surfaktan dan kadar masa penuaan (30 minit, dan 5, 10, 20, dan 30 hari) turut dikaji. Hasil penemuan menunjukkan bahawa, apabila kadar masa penuaan ditingkatkan, saiz kristal berkurangan dan penghasilan gumpalan besar tidak ditemui. Justeru, kadar masa penuaan optima dipilih untuk sintesis bahan ceria dan bahan ceria yang diubah suai, Fe-CeO 2 /TiO 2 , melalui kaedah impregnasi. Seterusnya, bahan-bahan ini dianalisis melalui sistem pembelauan sinar-X (XRD), program penjerap bersuhu-CO 2 (CO 2 -TPD), dan mikroskop elektron pengimbas pancaran medan (FESEM) untuk mengkaji kesan penambahan surfaktan dan kadar masa penuaan.Kata kunci: kation, ceria, kristal, pemendakan, surfaktan ISSN -2506Nor Aqilah et al: ROOM TEMPERATURE SYNTHESIS OF CERIA BY THE ASSISTED OF CATIONIC SURFACTANT AND AGING TIME 405 Introduction Rare earth elements are an interesting prospect for research due to its potential of application in ma...

Toward High-Value Hydrocarbon Generation by Photocatalytic Reduction of CO2 in Water Vapor

“…Generally, it is the direct reaction of CO 2 with oxygen atom or in a way with both oxygen and metal atoms from the catalyst that leads the formation of m-CO 3 2– and b-CO 3 2– . On the other hand, the combination of CO 2 and surface hydroxyls gives rise to the formation of HCO 3 – . − Several characteristic TPD peaks were observed in Figure d, which can be assigned to HCO 3 – (300–420 °C), b-CO 3 2– (500–700 °C), and m-CO 3 2– (680–850 °C). The uptake capacity of CO 2 on the photocatalysts followed the order of 0.02%Co-1%Cu/TiO 2 > 1%Cu/TiO 2 > TiO 2 in correlation with their specific surface areas.…”