Physicochemical Studies of Ni-, Co-, and Pt- Promoted Movnbox Catalysts Synthesised by Impregnation Method

Wong, MT; Ramli, Irmawati; Ahangar, Hossein Abbastabar; Taufiq-Yap, Yun Hin; Tan, Yuwei; Muhamad, Ernee Noryana

doi:10.13005/ojc/280109

Cited by 3 publications

(3 citation statements)

References 23 publications

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“…The occurrence of multiple reduction peaks indicates the presence of a number of reducible metal oxide species present in the catalyst. [24,25]. Additionally, reduction of Nb 5+ to Nb 4+ occur at around 1243 K [26].…”

Section: Reducibility Propertiesmentioning

confidence: 98%

EFFECT OF pH ON THE PHYSICOCHEMICAL PROPERTIES AND REDUCIBILITY OF MoVTeNbOx CATALYSTS

Ramli¹

2016

MJAS

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A range of MoVTeNbOx catalysts were synthesised by slurry method assisted with a microwave irradiation. The pH of the synthesis solution was varied at pH = 1, 3, 5, and 7 and the obtained solid were calcined in air at 553 K for 1 hour and followed in N 2 at 873 K for 2 hours. The calcined samples were characterised and their reduction properties were evaluated. The pH of the synthesis solution was shown to affect the physicochemical properties where the formation of orthorhombic M1 phase was obtained for catalysts prepared at pH 1 and 3. The reducibility of the catalyst is improved for catalyst prepared at pH 3 as compared to those prepared at pH 1. Although higher synthesised pH (5 and 7) gave much higher reducibility of the metal oxides, however the removable oxygen could be of the unselective ones.Keywords: MoVTeNbOx catalysts, pH, reducibility, propane, acrylic acid Abstrak Satu siri mangkin MoVTeNbOx telah disintesis menggunakan kaedah buburan dibantu oleh radiasi gelombang mikro. Nilai pH bagi larutan sintesis telah dikaji pada pH = 1, 3, 5, dan 7 dan pepejal yang diperolehi telah dikalsin dalam udara pada 553 K selama 1 jam dan diikuti dalam nitrogen pada 873 K selama 2 jam. Sampel terkalsin telah dicirikan dan sifat kebolehturunan telah dikaji. Di dapati, pH bagi larutan sintesis memberi kesan kepada ciri fizikokimia di mana pembentukan fasa ortorombik M1 telah terjadi bagi mangkin yang disediakan pada pH 1 dan 3. Kebolehturunan mangkin ini dipertingkatkan bagi mangkin yang disediakan pada pH 3 berbanding yang disediakan pada pH 1. Walaupun mangkin yang disediakan pada pH yang lebih tinggi (5 dan 7) memberikan kebolehturunan logam oksida lebih tinggi, namun penyingkiran oksigen mungkin menjadi tidak selektif.Kata kunci: mangkin MoVTeNbOx, pH, kebolehturunan, propana, asid akrilik IntroductionMoVTeNbOx is a quaternary mixed metal oxide catalyst consists of four different elements which are molybdenum, vanadium, tellurium and niobium. The catalyst is reportedly the most effective catalyst system for the vapour phase catalytic oxidation of propane to form acrylic acid [1][2][3][4][5][6]. It is because the catalyst contains necessary active sites which is fundamental in propane oxidation [7]. The active MoVTeNbOx system possesses two crystalline phases which are orthorhombic M1 phase, Te 2 M 20 O 57 (M = Mo, V, Nb), and hexagonal M2 phase, Te 0.33 MO 3.33 (M = Mo, V, Nb) [8]. The significant difference exists among these two phases is that the M1 phase contains V 5+ centres, as an agent for propane activation [4,7]. Meanwhile, M2 is incapable of activating propane, but it does convert

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Section: Reducibility Propertiesmentioning

confidence: 98%

EFFECT OF pH ON THE PHYSICOCHEMICAL PROPERTIES AND REDUCIBILITY OF MoVTeNbOx CATALYSTS

Ramli¹

2016

MJAS

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“…This phenomenon is possibly due to the successive steps of metal oxide reduction in the multicomponent catalysts. Reduction of MoO n (Mo 6+ → Mo 4+ and Mo 4+ → Mo 0 ) occurs at 948 and 995K (Wong et al 2012), VO n reduced at 913 and 943K (V 5+ → V 4+ and V 4+ → V 0 ) and Nb reduced at 1243 K (Nb 5+ → Nb 4+ ) (Pereira et al 2000). The multiple reductions reckon that the catalysts have a kinetically different oxygen species.…”

Section: Temperature Programmed Reduction In Hydrogen (H 2 -Tpr)mentioning

confidence: 99%

“…Unfortunately, these resources are usually used for electricity generation in industry and for domestic cooking. Therefore, there is a need to upgrade these alkanes into higher value product, for example by converting the alkanes into petrochemicals (Beato et al 2006;Irmawati et al 2011;Wong et al 2012). Since these alkanes have the potential of being the raw materials for selective oxidation into valuable petrochemical products, much effort has been undertaken in order to develop novel catalyst for this reaction.…”

Section: Introductionmentioning

confidence: 99%

Physicochemical Properties of MoVTeNb Mixed Oxide Catalysts Synthesized using Different Vanadium Sources

Sidek¹,

Ramli²,

Zainuddin³

et al. 2021

JSM

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The use of different vanadium sources in the synthesis of multi-metal MoVTeNb oxide catalysts has been investigated for their effect on the physicochemical properties of catalysts. Metal oxides were synthesized by slurry method assisted with a microwave irradiation. Vanadium pentoxide (V2O5), vanadyl sulphate (VOSO4) and ammonium metavanadate (NH4VO3) were used as the vanadium sources, respectively. X-ray diffraction (XRD) pattern showed the existence of orthorhombic (M1) phases in all catalysts. The catalyst prepared using V2O5 produced the highest formation of the phase. This was further supported by Inductive Couple Plasma-Atomic Emission Spectroscopy (ICP-AES), which showed that the V2O5 catalyst has the highest V: Mo ratio, mainly responsible for the high catalytic activity. Temperature Programmed Reduction in Hydrogen (H2-TPR) showed better reducibility for the catalyst when compared to the others. Temperature Programmed Reaction (TPRn) confirmed that the oxidants active for propane conversion into acrylic acid were originated from the lattice of the catalyst.

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Mo3VOx catalyst in biomass conversion: A review in structural evolution and reaction pathways

Julkapli

2017

International Journal of Hydrogen Energy

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Physicochemical Studies of Ni-, Co-, and Pt- Promoted Movnbox Catalysts Synthesised by Impregnation Method

Cited by 3 publications

References 23 publications

EFFECT OF pH ON THE PHYSICOCHEMICAL PROPERTIES AND REDUCIBILITY OF MoVTeNbOx CATALYSTS

EFFECT OF pH ON THE PHYSICOCHEMICAL PROPERTIES AND REDUCIBILITY OF MoVTeNbOx CATALYSTS

Physicochemical Properties of MoVTeNb Mixed Oxide Catalysts Synthesized using Different Vanadium Sources

Mo3VOx catalyst in biomass conversion: A review in structural evolution and reaction pathways

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