Malaysian Journal of Analytical Sciences Vol 21 No 4 (2017): 907 - 913

DOI: https://doi.org/10.17576/mjas-2017-2104-17

 

 

 

EFFECT OF RHODIUM ADDITIVE ON THE REDUCTION BEHAVIOUR OF IRON OXIDE IN CARBON MONOXIDE ATMOSPHERE

 

(Kesan Penambahan Rodium Terhadap Tindak Balas Penurunan Ferum Oksida Di Dalam Atmosfera Karbon Monoksida)

 

Tengku Shafazila Tengku Saharuddin¹, Fairous Salleh², Alinda Samsuri³, Norliza Dzakaria², Rizafizah Othaman², Mohammad Bin Kassim², Mohammad Wahab Mohammad Hisham², Mohd Ambar Yarmo²*

¹Faculty of Science and Technology,

Universiti Sains Islam Malaysia, 71800 Nilai, Negeri Sembilan, Malaysia

²School of Chemical Sciences and Food Technology, Faculty of Science and Technology,

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

³Centre for Defense Foundation Studies,

Universiti Pertahanan Nasional Malaysia, Kem Sungai Besi, 57000 Kuala Lumpur, Malaysia

 

*Corresponding author:  ambar@ukm.edu.my

 

 

Received: 28 November 2016; Accepted: 27 April 2017

 

 

Abstract

This study was carry out to investigate the effect of 3% rhodium on the reduction behaviour of iron oxide by (10%, v/v) carbon monoxide in nitrogen as a reductant. The Rh/Fe₂O₃ samples were prepared by impregnation method and the reduction behavior of Rh/Fe₂O₃ and pure Fe₂O₃ were investigated by using temperature programmed reduction (TPR). The prepared samples and the reduced phases were characterized by X-ray diffraction spectroscopy (XRD). The results indicate that Rh/Fe₂O₃ give a better reducibility compared to Fe₂O₃ with a complete reduction at 650 °C, which is 250 °C lower than Fe₂O₃. The TPR results indicate that the reduction of Fe₂O₃ proceed in three steps reduction (Fe₂O₃ → Fe₃O₄ → FeO → Fe) with Fe₃O₄ and FeO as intermediate states while for Rh/Fe₂O₃ as the TPR result showed the overlapping of second and third peak (Fe₃O₄ → FeO and FeO → Fe) at higher temperature. Addition of Rh may possibly reduce the formation of stable FeO that stable at higher temperature by accelerates the direct reduction of Fe₃O₄→ Fe so the reduction process of Fe₂O₃ become faster. The XRD pattern shows the diffraction peaks of Rh/Fe₂O₃ is more intense with improved crystallinity for the characteristic peaks of Fe₂O₃ compared to pure Fe₂O₃. No visible sign of rhodium particles peaks in the XRD spectrum that indicates the Rh particles loaded onto the iron oxide are well dispersed. The well dispersed Rh onto the iron oxide and the ability to reduce the sintering effect to the iron oxide also has been confirmed by FESEM. The study shows that addition of Rh gives a better reducibility of iron oxide is also due to the ability of Rh to interact with CO as confirmed by the thermodynamic data with higher surface area compared to Fe₂O₃.

 

Keywords:  temperature programmed reduction, rhodium, ferum oxide, carbon monoxide

 

Abstrak

Kajian ini dijalankan untuk melihat pengaruh 3% rodium kepada kelakuan penurunan ferum oksida di mana karbon monoksida (10%, v/v) di dalam nitrogen digunakan sebagai agen penurunan. Sampel Rh/Fe₂O₃ disintesis menggunakan kaedah impregnasi dan kelakuan penurunan dikaji menggunakan teknik suhu penurunan berprogram (TPR). Fasa - fasa yang terbentuk dicirikan menggunakan teknik pembelauan sinar X (XRD). Keputusan menunjukkan Rh/Fe₂O₃ memberikan kelakuan penurunan yang lebih baik berbanding Fe₂O₃ sahaja dengan penurunan lengkap berlaku pada suhu 650 °C dimana suhu penurunan berkurangan sebanyak 250 °C berbanding suhu penurunan lengkap Fe₂O₃. Profil TPR menunjukkan bahawa penurunan ferum oksida melalui tiga langkah tindak balas penurunan (Fe₂O₃ → Fe₃O₄ → FeO → Fe) dengan Fe₃O₄ dan FeO merupakan fasa perantara, sementara, Rh/Fe₂O₃ pada suhu penurunan tinggi menunjukkan pertindihan diantara puncak kedua dan puncak ketiga (Fe₃O₄ → FeO and FeO → Fe). Penambahan Rh didapati mengurangkan penghasilan FeO yang stabil pada suhu tinggi dengan menggalakkan penurunan terus Fe₃O₄→ Fe menjadikan tindak balas penurunan lebih cepat. Difraktogram XRD bagi Rh/Fe₂O₃ menunjukkan peningkatan pada kehabluran puncak Fe₂O₃ berbanding ferum oksida tulen. Tiada puncak tambahan diperhatikan dimana ia menjelaskan bahawa zarah Rh yang dimuatkan pada ferum oksida telah tersebar dengan baik. Penyerakan yang baik oleh Rh di atas ferum oksida telah menunjukkan pengurangan kesan pensinteran terhadap ferum oksida yang telah dibuktikan melalui FESEM. Kajian menunjukkan penambahan Rh memberikan kesan yang baik kepada proses penurunan ferum oksida berdasarkan kebolehan Rh untuk berinteraksi dengan gas CO yang telah disahkan oleh pengiraan termodinamik dan peningkatan kepada luas permukaan berbanding Fe₂O₃ tulen_.

 

Kata kunci:  suhu penurunan berprogram, rodium, ferum oksida, karbon monoksida

 

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